The Money Mustache Community
Learning, Sharing, and Teaching => Do it Yourself Discussion! => Topic started by: Duchess of Stratosphear on March 31, 2019, 08:09:34 AM
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My house gets hot in the summer, and I have this sneaking feeling that the summers are only going to get hotter, so how do you keep your house cool? I'm especially interested in what to do for the windows on the west side of my house--awnings? shutters? solar screens? interior shades? I'm also curious about how feasible it is to install an attic fan.
The summers aren't super hot here but when the sun pours in those western windows, it sucks. What have you done to your house to keep the heat out? The cheaper and simpler the better, but I do think this is worth spending a little money on (maybe a few hundred bucks).
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I bought high quality room darkening curtains from Pottery Barn Kids. (The curtains are sold on the regular PB site, but they were cheaper on the kids site.) They have regular sales and coupons so you can get them at a discount. I’ve had one set for about 8 years and bought another set this year when I moved to a home with more south and west facing windows. They make a tremendous difference in how warm my place gets. I just use inexpensive tension rods to hold them up.
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Consider awnings in addition to curtains as they prevent the energy that dissipates as heat inside the house from actually reaching inside during the hottest parts of summer, while letting them in during the evening if needed and during the winter. Curtains alone with white backing can reduce heat gain but a lot of the energy gets dissipated as heat within the house since windows prevent infrared from escaping back out.
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I'm really interested in awnings, but it's seriously windy where I live, so I'm a bit afraid of fabric ones. Are wood awnings a thing? I am not seeing many on the Google.
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Dependent on many things, but outdoor landscaping can help a lot. Concrete is hot. Plants will help cool things down. And the big trees that shade the whole house make a HUGE impact. Yes, it takes decades to grow them. The later you plant them, the longer it'll be.
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You can purchase durable metal awnings from Costco.
Also, if you don’t want to wait for large trees to grow, consider making a trellis and having vines. They will actually function similar to awnings and can withstand high winds
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Solar screens make a dramatic difference. You can buy supplies and make them yourself easily.
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I always plant fast growing native trees on the west and north sides of the house. There is nothing you can do inside that works better than having a house in the shade.
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Thanks for the ideas! These windows are high up enough that I would need to plant container plants on the deck to shade them rather than trees, so I'm looking into what kinds of vines I can grow that will get big enough to quickly shade the windows. I am really interested in solar screens, and that seems relatively cheap, so I will do some more googling on that.
Abe, do you have a link to the Costco awnings? All I see are fabric ones.
Does anybody have experience with shutters? They seem expensive....
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Cellular shades coupled with heavy curtains work marvels to keep both light and heat out of the house during the day on the very sunny south side of our home. Turning off all electronic devices and switching off the power bars that have the wall-wart type charging adapters also makes a big difference (all those suckers put out heat!).
Generally, during the day things are tolerable heat wise . . . where it really impacts us is at night. We put ceiling fans in all of our bedrooms to make things more comfortable. I try to spend a lot of time outdoors in the heat so that my body gets more used to it. That, plus taking a cool shower before bed seems to help me get through the night. We do try to open windows up when it cools off in the evening, but when humidity gets up into 85 - 100% this strategy doesn't really work very well - slightly cooler but extremely sticky air is still uncomfy to sleep in. It it's really miserable, I'll go sleep in the basement where it's always a few degrees cooler and more comfortable than in the upper floor bedrooms.
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Dependent on many things, but outdoor landscaping can help a lot. Concrete is hot. Plants will help cool things down. And the big trees that shade the whole house make a HUGE impact. Yes, it takes decades to grow them. The later you plant them, the longer it'll be.
I second the mention of concrete.
https://www.apnews.com/fe99da5da0d4455eaf2d96842b83b577
Also relevant:
“The best time to plant a tree was 20 years ago. The second best time is now." - Someone Sometime
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I am definitely looking at cellular shades! Luckily, I don't have any concrete around me, which makes me very happy. My gravel road has grass growing up the middle of it, which is fine by me. It's cooler here than in the rest of the state, so I am probably just a big old wimp to be complaining. But the summers are getting hotter, so even here it's not as pleasant as back in the day. I think there are some easy things I can do to cool it down a bit.
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For a cheap and quick solution - standard aluminum foil - put it on the outside of the windows if you can - it will reflect the heat and stop it from entering your house.
If putting it on the outside won't work well (too high / too much outdoor weather exposure will tear the foil, etc.), then you can put it inside the windows. Or cover a exact size piece of cardboard with aluminum foil and stick it in the window - then you can take it down whenever you want.
It doesn't look the best, but it really keeps things cool and costs very, very little.
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I have a multiprong approach and I enjoy using it quite a bit, up until it reaches time to turn on the minisplit.
1890 Victorian converted to duplex, I live on the bottom floor.
I will be building a screen for the transom window above a really big picture window, which will greatly increase cross ventilation as there is otherwise no operable window in that half of the house. Prior to this, opening my front door would be the only way to allow the cool morning air in. Takeaway for everyone here - identify any chokepoints you have like this and if need be, add a window or build/commission a screen window.
I have a mix of solar and blackout shades on my western windows and a few solar shades on my eastern windows.
I have a very quiet and attractive chrome fan that I use in the morning to coax all the cool air in.
I have really tall double hung windows which can be utilized to let hot air out the tops of them. But I have fixed storm windows on top and screens on the bottom so not sure how much hot air is able to really escape.
On humid days over 85 or so, we close up windows, drawn down blinds, and turn on the minisplit - closing closet doors and doors to rooms deemed unworthy of AC, and ensuring our bedroom door is wide open so we have a nice cool evening for sleeping.
Since the temp drops at night, I do my best to convince my wife we don't need AC at night so I get the ceiling fan to draw air up and the double hungs in their up/down position. I sleep far better knowing I'm not drawing crazy amp hours all night... until it reaches a certain dew point :)
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Is it humid where you live? That makes a big difference in how tolerable the heat is. A second hand dehumidifier, even if just in the bedroom will help a lot. That's mainly what I use the AC for, then shut it off once the humidity is reduced. If you're going to plant a vine, try pole beans - might as well get something edible for your efforts! My house faces west, and luckily there are 2 big trees just 20 feet away, which REALLY helps. You can purchase larger trees rather than waiting for a stripling to grow, or plant a poplar closer to the house, with a slower growing tree further away, then once the poplar gets too big, cut it down and the other tree will be large enough to help cool the house. If you're planning to stay a while, that is.
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For the west facing windows, you want an exterior roller shade like this one:
https://www.amazon.com/Coolaroo-436612-Cordless-Southern-Protection/dp/B005X634VS
It is best to intercept the sunlight before it gets into your house. Once the sunlight comes in, it will heat up whatever it lands on which will radiate heat into the rest of your house. So interior curtains or shades don't really help. They are just another thing inside your house that absorb sunlight and radiate heat. You want this process to happen outside your house.
I put these exterior shades on my western windows and it made a noticeable difference. I added one little tweak to the installation, mounting the roller on wood blocks to create a bigger gap between the shade and my house. I was thinking this would help the breeze blow the heat off the shade so there's less of it to radiate off the shade through the window.
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My house gets hot in the summer, and I have this sneaking feeling that the summers are only going to get hotter, so how do you keep your house cool? I'm especially interested in what to do for the windows on the west side of my house--awnings? shutters? solar screens? interior shades? I'm also curious about how feasible it is to install an attic fan.
The summers aren't super hot here but when the sun pours in those western windows, it sucks. What have you done to your house to keep the heat out? The cheaper and simpler the better, but I do think this is worth spending a little money on (maybe a few hundred bucks).
Outside shutters and close them during the day. The shutters with angled slats are best because it still allows light in.
Is your attic insulated? You should put some cellulose in the attic. It makes a big difference. I hear, besides shutters, there is a brand of bug screening, where the tiny little holes are angled and can block 90% of direct sunlight. It might be worth it as well
I see some recs of curtains and cellular shades. These do not work because the heat is already inside the house and it will radiate and mix with the air inside.
Insulation, fans, solar screen for insects (also called privacy screens), awnings ... outside shutters, whole house fan (at night or morning once its cooler than inside, you can bring outdoor air inside and make the house cooler and reset the inside temp for the day - very advantageous during a long spell of hot day temperatures).
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So interior curtains or shades don't really help. They are just another thing inside your house that absorb sunlight and radiate heat.
Not so.
Yes, they absorb some sunlight. But their thermal mass is negligent, thus the amount of heat they will radiate is a tiny fraction of the heat that would be absorbed and radiated by flooring or furniture or what have you.
Anecdotes here and official data bear out this truth.
https://www.energy.gov/energysaver/energy-efficient-window-attachments
Agreed that exterior window treatments are more effective, but the difference is nowhere near as dramatic as you suggest.
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So interior curtains or shades don't really help. They are just another thing inside your house that absorb sunlight and radiate heat.
Not so.
Yes, they absorb some sunlight. But their thermal mass is negligent, thus the amount of heat they will radiate is a tiny fraction of the heat that would be absorbed and radiated by flooring or furniture or what have you.
Anecdotes here and official data bear out this truth.
https://www.energy.gov/energysaver/energy-efficient-window-attachments
Agreed that exterior window treatments are more effective, but the difference is nowhere near as dramatic as you suggest.
I get a different conclusion from reading that page. The only interior window treatments claimed to be very effective are tight fitting, insulated ones that attempt to turn the window into a wall. About exterior shades, the page says: "They are most effective at reducing solar heat gain."
Once the sunlight enters the house, that energy must become heat, regardless of the thermal mass of what the sunlight falls on. You can try to trap that heat against the window, but that's hard. Most interior window coverings don't have much R value and also allow air flow through and around them. That's not going to be effective. An exterior shade doesn't need to be tight fitting or have R value. That practical difference makes a dramatically better result.
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Good stuff! Thanks y'all.
I think one issue with cooling my house is that I have casement windows. From some comments and things I've read, double hung windows are better at letting you control air flow. If I have to replace windows at some point, I'll likely go with double hung, but that's a far future thing.
tyler.close, I like the idea of something on the outside of the house, but a roller shade would likely just get beaten to death by the wind and keep me awake at night unless there is a good way to really secure it. Shutters would probably be better, but damn, they are expensive, and, one window is super high and another window is in a door and shutters would seem awkward there. Still, it could be worth it; cheaper than a minisplit...
J. Boogie, I am curious about your minisplit. What kind of climate do you live in? Where I live can be humid, so even though it's not as hot as other parts of the state, the humidity is often what keeps me from sleeping well in the summer. I'd really like to avoid installing a minisplit, but as I get older, I have less tolerance for clammy sleeping. Do you use it for heat as well?
MrSal, my attic (or attic-like space) is insulated with fiberglass bats (R-30 is what code requires, I think), but I wonder how those hold up over time if critters get up in there and make nests. It's not a large space and I can't get into it, so investigating this would be a major thing that probably won't happen unless the house starts getting super cold in winter.
So for the high upstairs window, I'm thinking something interior works best. For the downstairs window, lots of things could work. For the door, maybe a screen door with the solar screen in it? Plus lots of beans :)
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You did not say where you are at, but I live in the high desert of SE AZ and we have very large south facing windows. We had all the windows in the house tinted with ceramic tint and have cellular shades on them. We also open the windows at night to let in the cool air and then close them in the morning.
Also, when I was looking for similar advice I searched for "passive solar design" and there are several government sites with good information on ways to reduce your energy usage with small changes, such as plants, shades etc.
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Once the sunlight enters the house, that energy must become heat, regardless of the thermal mass of what the sunlight falls on. You can try to trap that heat against the window, but that's hard. Most interior window coverings don't have much R value and also allow air flow through and around them. That's not going to be effective. An exterior shade doesn't need to be tight fitting or have R value. That practical difference makes a dramatically better result.
No argument that the sunlight is going to warm up anything it hits. But if it's making a 2lb shade 80 degrees instead of 70 degrees, that's not going to be very effective at heating the rest of the room. The window jambs and stool will be exposed to the sun (as well as the reflected rays if the shade is bouncing radiation back) and heat up, that's true. They probably weigh 8 lbs or so depending on window size. So, to your point, the jambs and stool will heat the air between the shade and window and that heated air will diffuse. But the average home interior weighs maybe 50,000 pounds so the 10 lbs exposed to the sun represents ~ .0002 percent of the interior being heated by the sun.
So yeah, I'd rather have 0% of my interior being heated by the sun. But I'm just fine with .0002% if it means I can operate it manually from inside, have the aesthetic exterior I want, and not have to worry about wind and rain beating down on it.
Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
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J. Boogie, I am curious about your minisplit. What kind of climate do you live in? Where I live can be humid, so even though it's not as hot as other parts of the state, the humidity is often what keeps me from sleeping well in the summer. I'd really like to avoid installing a minisplit, but as I get older, I have less tolerance for clammy sleeping. Do you use it for heat as well?
I live in St. Paul, MN.
Some days get really humid - we used a window unit before we put in the minisplit. It's AC only, which is fine - we've got a great boiler system that provides plenty of heat.
It hasn't yet been figured out how to minimize humidity in a passive way. Maybe we can develop this technology, but until then we've got AC and dehumidifiers. I'd use AC, as dehumidifiers still use plenty of energy and they also create heat.
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Do you know how much insulation you have in your attic?
Not only does it keep heat in in the winter, it can help keep the cool in in the summer.
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Do you know how much insulation you have in your attic?
Not only does it keep heat in in the winter, it can help keep the cool in in the summer.
Dang, beat me to it.
People often forget that insulation works both ways; keeps heat in or out! Insulation cost about 15% of windows and has more impact. That giant solar heater above peoples head lets in more heat than a window.
If you want to spend a lot of money, redo windows. If you want it to be effective, more insulation. R-30 isn't much, the code is a minimum standard, just like getting a D- means you passed.
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
To the contrary, the thermal mass of various objects (as well as their efficacy in absorbing the sun's radiation) is the most relevant factor in the entire equation.
Designing so that the sun shines on intentionally heavy materials known to readily absorb solar energy is a major part of passive solar design.
To avoid solar gain, you would do the opposite - ensure the sun does NOT shine on heavy materials that readily absorb solar energy. And you can do that by having the sun shine on a blind instead.
https://www.energy.gov/energysaver/energy-efficient-home-design/passive-solar-home-design
https://en.wikipedia.org/wiki/Trombe_wall
https://sciencing.com/materials-absorb-reflect-solar-energy-8878.html
And as long as we're here on this forum...
http://www.mrmoneymustache.com/2011/09/01/what-is-thermal-mass-and-how-can-it-make-you-money/
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Do you know how much insulation you have in your attic?
Not only does it keep heat in in the winter, it can help keep the cool in in the summer.
Dang, beat me to it.
People often forget that insulation works both ways; keeps heat in or out! Insulation cost about 15% of windows and has more impact. That giant solar heater above peoples head lets in more heat than a window.
If you want to spend a lot of money, redo windows. If you want it to be effective, more insulation. R-30 isn't much, the code is a minimum standard, just like getting a D- means you passed.
Because of the way my house is built, it would be really hard to redo the "attic" insulation. There isn't away to get in there. I don't know how to explain it, but the upstairs is one big space with a 3 foot hip wall and then the roof starts. There is a flat ceiling in the middle (below the roof peak) where I could cut into the attic space if I had to (and I've thought of doing this to install a whole house fan). I could put more insulation in that part, maybe, but getting somebody to cut into that space sounds expensive. I'm not explaining this well, sorry.
If I had it to do all over again, I would build using passivhaus technology. Oh well.
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I don't know how to explain it, but the upstairs is one big space with a 3 foot hip wall and then the roof starts. There is a flat ceiling in the middle (below the roof peak) where I could cut into the attic space if I had to (and I've thought of doing this to install a whole house fan). I could put more insulation in that part, maybe, but getting somebody to cut into that space sounds expensive. I'm not explaining this well, sorry.
It sounds like your the unconditioned spaces are disconnected - like there might be 2-4 sections above the eaves (beyond the knee wall), and then there is one at the peak. Usually they are connected by ventilation chutes which allow air to come up the eaves and out the ridge vent or alternative (as hip roofs don't often lend themselves all that well to ridge venting).
If you live in a snow heavy climate, ice dams and major icicles can potentially be a sign you have inadequate attic insulation - but they can form during a thaw-freeze cycle regardless of insulation too. Widespread ice dams among your neighbors usually means there was a thaw and subsequent freeze and offers little insight to your insulation situation.
TBH, it sounds like you need a minisplit to minimize humidity and sleep comfortably. And a solar array to power it might be a decent idea as well, always a good investment when market valuations are high.
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I would love to someday incorporate a PV system, but that is probably out of my budget range right now, which is a shame because I have a good site for it.
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
To the contrary, the thermal mass of various objects (as well as their efficacy in absorbing the sun's radiation) is the most relevant factor in the entire equation.
Designing so that the sun shines on intentionally heavy materials known to readily absorb solar energy is a major part of passive solar design.
To avoid solar gain, you would do the opposite - ensure the sun does NOT shine on heavy materials that readily absorb solar energy. And you can do that by having the sun shine on a blind instead.
That last part is where you've gone wrong. Both high mass and low mass objects turn sunlight into heat. High mass ones just release that heat more slowly, allowing it to be stored for later. So on a sunny winter day, a high mass object can store heat from sunlight into the night. That high mass object will take longer to heat up though. A low mass object will heat up faster in the sunlight, but won't store much heat into the night. It releases its heat right away. Think about sitting on a stone bench first thing in the morning versus a folding camp chair. On a sunny summer day, that low mass object will act the same: heating up fast and releasing the heat fast. If that low mass object is in your house, it is releasing the heat into your house.
Consider also the paradox in your current model of how things work. The sunlight has entered your house. That's energy in your house. You can't make that energy disappear. You can pump the heat out or store it or contain it, but you can't make it disappear. It sounds like you think the blind is making the energy disappear.
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I installed solar electric panels on my roof three years ago. One of the unanticipated benefits I experienced is that the panels actually shade the roof. My upstairs has a cathedral ceiling (no attic) with just a thin layer of insulation between the ceiling and roof above. The roof used to get very hot in the summer and it would cause the room below to heat up. Now the solar panels shade the roof and keeps the shingles and the room below slightly cooler. There is a small air gap between the panels and the roof so the heat does not transfer from the panels to the roof.
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Whole house fans would be a good option, but best to use later in the day to add cool air to the circulation. Check with your utilities provider, sometimes they offer a rebate. Also, tile flooring feels coolers on my feet than carpets/rug. Dress lightly - look especially for light weight cooling fabrics for shirts and pants. Instead of using central AC, you can put a small air conditioner in a small room.
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
To the contrary, the thermal mass of various objects (as well as their efficacy in absorbing the sun's radiation) is the most relevant factor in the entire equation.
Designing so that the sun shines on intentionally heavy materials known to readily absorb solar energy is a major part of passive solar design.
To avoid solar gain, you would do the opposite - ensure the sun does NOT shine on heavy materials that readily absorb solar energy. And you can do that by having the sun shine on a blind instead.
That last part is where you've gone wrong. Both high mass and low mass objects turn sunlight into heat. High mass ones just release that heat more slowly, allowing it to be stored for later. So on a sunny winter day, a high mass object can store heat from sunlight into the night. That high mass object will take longer to heat up though. A low mass object will heat up faster in the sunlight, but won't store much heat into the night. It releases its heat right away. Think about sitting on a stone bench first thing in the morning versus a folding camp chair. On a sunny summer day, that low mass object will act the same: heating up fast and releasing the heat fast. If that low mass object is in your house, it is releasing the heat into your house.
Consider also the paradox in your current model of how things work. The sunlight has entered your house. That's energy in your house. You can't make that energy disappear. You can pump the heat out or store it or contain it, but you can't make it disappear. It sounds like you think the blind is making the energy disappear.
Isn't the point that the blinds limit the volume of space which is heated by sunlight? As in, just the few cubic inches between the window and the blind rather than the several cubic feet/metres between the window and the floor/walls/furniture?
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Isn't the point that the blinds limit the volume of space which is heated by sunlight? As in, just the few cubic inches between the window and the blind rather than the several cubic feet/metres between the window and the floor/walls/furniture?
A home's exterior walls are five inches thick, air sealed, stuffed with good insulation and yet still allow some heat to pass through them. Do you really think the blinds are blocking any heat? Air moves freely around them and they are paper thin.
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Isn't the point that the blinds limit the volume of space which is heated by sunlight? As in, just the few cubic inches between the window and the blind rather than the several cubic feet/metres between the window and the floor/walls/furniture?
A home's exterior walls are five inches thick, air sealed, stuffed with good insulation and yet still allow some heat to pass through them. Do you really think the blinds are blocking any heat? Air moves freely around them and they are paper thin.
I do. The cellular shades we've got significantly block both heat and cold as well as air movement.
In the summer when you pull the blinds up the air on the window side is 10 - 15 degrees warmer than the air on the bedroom side. In the winter if you leave the shades down for a couple days significant ice will accumulate on the window . . . if you leave them up no ice will accumulate on the windows.
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
To the contrary, the thermal mass of various objects (as well as their efficacy in absorbing the sun's radiation) is the most relevant factor in the entire equation.
Designing so that the sun shines on intentionally heavy materials known to readily absorb solar energy is a major part of passive solar design.
To avoid solar gain, you would do the opposite - ensure the sun does NOT shine on heavy materials that readily absorb solar energy. And you can do that by having the sun shine on a blind instead.
That last part is where you've gone wrong. Both high mass and low mass objects turn sunlight into heat. High mass ones just release that heat more slowly, allowing it to be stored for later. So on a sunny winter day, a high mass object can store heat from sunlight into the night. That high mass object will take longer to heat up though. A low mass object will heat up faster in the sunlight, but won't store much heat into the night. It releases its heat right away. Think about sitting on a stone bench first thing in the morning versus a folding camp chair. On a sunny summer day, that low mass object will act the same: heating up fast and releasing the heat fast. If that low mass object is in your house, it is releasing the heat into your house.
Consider also the paradox in your current model of how things work. The sunlight has entered your house. That's energy in your house. You can't make that energy disappear. You can pump the heat out or store it or contain it, but you can't make it disappear. It sounds like you think the blind is making the energy disappear.
It sounds like you think a 2lb blind heated to 80 degrees by the sun can significantly affect the temperature of a 100,000 lb 75 degree house.
The sun's rays have far different effects on different materials. Stepping on grass vs stepping on blacktop is a good example of this. Your logic is proved wrong by the existence of the urban heat island effect. These heavy, sun-absorbing materials like concrete and steel make everything around them hotter. Your argument would have the grassy green areas at the same temperatures because they're simply releasing their heat right away.
In fact, this is such a factor here that it overrides whether or not something is inside vs outside of a house.
US Dept of Energy:
"Window awnings can reduce solar heat gain in the summer by up to 65% on south-facing windows and 77% on west-facing windows....
In cooling seasons, cellular shades can reduce unwanted solar heat through windows by up to 80%"
The reason for this is that cellular shades are made of such a light, heat-resistant material compared to an awning which must be durable and able to withstand wind, rain, and other elements. The awning will absorb the sunlight and slowly transfer the heat to your house which it is connected to. It is obviously still extremely effective, especially if is light colored or reflective.
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A home's exterior walls are five inches thick, air sealed, stuffed with good insulation and yet still allow some heat to pass through them. Do you really think the blinds are blocking any heat? Air moves freely around them and they are paper thin.
I do. The cellular shades we've got significantly block both heat and cold as well as air movement.
In the summer when you pull the blinds up the air on the window side is 10 - 15 degrees warmer than the air on the bedroom side. In the winter if you leave the shades down for a couple days significant ice will accumulate on the window . . . if you leave them up no ice will accumulate on the windows.
Congratulations, it sounds like you have tightly installed, well-insulated window treatment. That makes your window more wall-like than the window with loose, paper-thin blinds that I was addressing.
It's hard to know what to think of the 10-15 degree difference in air temperature during the summer. I assume you're running the A/C, so just setting that to a lower temperature is going to make for a bigger temperature difference. I don't know how much work the A/C is doing to maintain that 10-15 degree difference. You could try leaving the blinds open one day to see how much more energy your A/C consumes.
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A home's exterior walls are five inches thick, air sealed, stuffed with good insulation and yet still allow some heat to pass through them. Do you really think the blinds are blocking any heat? Air moves freely around them and they are paper thin.
I do. The cellular shades we've got significantly block both heat and cold as well as air movement.
In the summer when you pull the blinds up the air on the window side is 10 - 15 degrees warmer than the air on the bedroom side. In the winter if you leave the shades down for a couple days significant ice will accumulate on the window . . . if you leave them up no ice will accumulate on the windows.
Congratulations, it sounds like you have tightly installed, well-insulated window treatment. That makes your window more wall-like than the window with loose, paper-thin blinds that I was addressing.
It's hard to know what to think of the 10-15 degree difference in air temperature during the summer. I assume you're running the A/C, so just setting that to a lower temperature is going to make for a bigger temperature difference. I don't know how much work the A/C is doing to maintain that 10-15 degree difference. You could try leaving the blinds open one day to see how much more energy your A/C consumes.
We typically do not run the air conditioning during the summer (usually reserving it for the the times in the summer where humidity is at about 90% percent). 10 - 15 degrees difference is the difference between the cool interior (which we cool off by opening windows at night) and the air heated by the sun coming in through the window.
I have occasionally forgotten to close the blinds in the morning in one of the upstairs bedrooms, and temperature will be much warmer in the afternoon in the room.
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No AC Brick home in Denver with big windows facing directly E/W so morning and night got alot of glare.
We did a few things:
1. Light blocking curtains with a 2nd set of lighter curtains underneath so when the sun was on the other side we could open the lightblocking curtains and get more light.
2. Ceiling fans.
3. Window fans box fans and cyclone fans. Come evening first we would open up the front(east) windows and side windows and put the fans in pulling the hot air out. Once sun got farther down open the back with fans blowing in creating crossbreeze. We also would have fans in doorways to create more crossbreeze.
4. Get rid of your incandescent/halide bulbs-those get hot.
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Air is a very good insulator.
Curtains keeping an air barrier is a decent layer of insulation. The sun puts out a lot of heat too so windows directly facing sun that have curtains can have a significant impact.
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See if your electricity company has a program to do home energy assessments. In California most of them have free or cheap programs to come out and help identify areas where you can reduce energy usage. They usually offer cheap or free options for things like replacing weather stripping, putting in led bulbs, etc.
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So far I've gotten one cellular shade installed, and I'm looking into solar screen that I can put up on the outside of that window as well as growing some plants to shade it.
I do need to do an energy audit! I've looked into it before but haven't taken the leap. I can't afford to do any major insulation upgrades right now, so I sort of just don't want to know how bad it might be.
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My house is the coolest on the block because I live there.
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I don’t like the look of heavy drapes and prefer a minimalist look. I have 7 large west facing windows in my living room. The outside wall is stone, while a nice accent to the house, absorbs heat in the summer. My view is nice, but in the summer it gets hot! I cut pieces of white bathroom paneling (teachers also use this material to make white boards for kids to use in math) from 4x8 sheets to fit each window. You can either completely cover the window space or create a panel that allows a bit of space for some light. I store them in a closet in the living room. An added bonus is the panels are great for blocking light when you want to watch TV on a bright day.
I created these panels for my bedroom windows too. There are times you want greater darkness in a bedroom and they do the trick! They are easily stored under the bed. The panels are tons cheaper than drapes and are only out when needed.
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Our climate is hot and humid much of the year. I use a combination of Japanese sudare which let airflow through even when sun's shining https://www.ebay.com/itm/Japanese-Traditional-Bamboo-Blind-Sudare-Kibune-made-by-Tokiwa-Sudare-/183764474485 (mine are 50-100 years old from a temple and much cheaper), super powerful ceiling fan and bedroom fans, only using AC if things are really bad (like this week) and blackout curtains in the bedroom. The architecture is designed for hot climates before aircon: long, narrow, shaded but well ventilated too like a shotgun house or shophouse design.
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My house is the coolest on the block because I live there.
(https://i.imgur.com/71Fipym.jpg)
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We put R49 batts in the attic and then added Gila brand thermal window tint (from Home Depot) to most all of our windows. It made a huge improvement to do the tint. It's not super dark but reflects 73% of the heat and 99% of UV rays. Made differece of 5-10* in most locations. Also put a light mesh "awning" over the porch and it was a 15* difference... I measured with my thermal laser tool from Harbor freight.
We also have thermal curtains to help cover windows and keep the cool/heat in depending on the weather. Also ceiling fans.
Yesterday it was 96*. A/C set to 76* inside... I only heard it kick on a couple of times to maintain the temp!!
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
To the contrary, the thermal mass of various objects (as well as their efficacy in absorbing the sun's radiation) is the most relevant factor in the entire equation.
Designing so that the sun shines on intentionally heavy materials known to readily absorb solar energy is a major part of passive solar design.
To avoid solar gain, you would do the opposite - ensure the sun does NOT shine on heavy materials that readily absorb solar energy. And you can do that by having the sun shine on a blind instead.
That last part is where you've gone wrong. Both high mass and low mass objects turn sunlight into heat. High mass ones just release that heat more slowly, allowing it to be stored for later. So on a sunny winter day, a high mass object can store heat from sunlight into the night. That high mass object will take longer to heat up though. A low mass object will heat up faster in the sunlight, but won't store much heat into the night. It releases its heat right away. Think about sitting on a stone bench first thing in the morning versus a folding camp chair. On a sunny summer day, that low mass object will act the same: heating up fast and releasing the heat fast. If that low mass object is in your house, it is releasing the heat into your house.
Consider also the paradox in your current model of how things work. The sunlight has entered your house. That's energy in your house. You can't make that energy disappear. You can pump the heat out or store it or contain it, but you can't make it disappear. It sounds like you think the blind is making the energy disappear.
It sounds like you think a 2lb blind heated to 80 degrees by the sun can significantly affect the temperature of a 100,000 lb 75 degree house.
The sun's rays have far different effects on different materials. Stepping on grass vs stepping on blacktop is a good example of this. Your logic is proved wrong by the existence of the urban heat island effect. These heavy, sun-absorbing materials like concrete and steel make everything around them hotter. Your argument would have the grassy green areas at the same temperatures because they're simply releasing their heat right away.
In fact, this is such a factor here that it overrides whether or not something is inside vs outside of a house.
US Dept of Energy:
"Window awnings can reduce solar heat gain in the summer by up to 65% on south-facing windows and 77% on west-facing windows....
In cooling seasons, cellular shades can reduce unwanted solar heat through windows by up to 80%"
The reason for this is that cellular shades are made of such a light, heat-resistant material compared to an awning which must be durable and able to withstand wind, rain, and other elements. The awning will absorb the sunlight and slowly transfer the heat to your house which it is connected to. It is obviously still extremely effective, especially if is light colored or reflective.
I'm going to hop on Tyler's boat here. The thermal mass is completely irrelevant in scenario (though it plays a large role in home comfort for different reasons). The reason cellular shades work so well is that they 1) reflect some sunlight back out the window and 2) are insulated well enough to significantly increase the temperature between the shade and the wall, thereby allowing for decreased conductive/convective heat intake during the summer. If the cellular shade wasn't placed up against the window but was instead placed on the floor where the sun was shining, you'd find your house heating up just as fast as if that shade wasn't on the floor at all.
As to the comment on the urban heat island effect, it isn't the thermal mass (I'm not sure but I would think urban areas have less insulative properties than urban, thereby increasing effective thermal mass); on the contrary, from what I've read it's mostly due to decreased reflectivity, decreased evapotranspiration, decreased wind, and decreased solid angle exposure to the cold night sky.
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Just my take. Obviously my numbers are kind of guesstimated but if there are any fundamental errors feel free to correct them.
Again, the mass of various objects is not relevant. The sunlight has the same amount of energy regardless of the mass of the object it shines on. All that sunlight energy becomes heat.
To the contrary, the thermal mass of various objects (as well as their efficacy in absorbing the sun's radiation) is the most relevant factor in the entire equation.
Designing so that the sun shines on intentionally heavy materials known to readily absorb solar energy is a major part of passive solar design.
To avoid solar gain, you would do the opposite - ensure the sun does NOT shine on heavy materials that readily absorb solar energy. And you can do that by having the sun shine on a blind instead.
That last part is where you've gone wrong. Both high mass and low mass objects turn sunlight into heat. High mass ones just release that heat more slowly, allowing it to be stored for later. So on a sunny winter day, a high mass object can store heat from sunlight into the night. That high mass object will take longer to heat up though. A low mass object will heat up faster in the sunlight, but won't store much heat into the night. It releases its heat right away. Think about sitting on a stone bench first thing in the morning versus a folding camp chair. On a sunny summer day, that low mass object will act the same: heating up fast and releasing the heat fast. If that low mass object is in your house, it is releasing the heat into your house.
Consider also the paradox in your current model of how things work. The sunlight has entered your house. That's energy in your house. You can't make that energy disappear. You can pump the heat out or store it or contain it, but you can't make it disappear. It sounds like you think the blind is making the energy disappear.
It sounds like you think a 2lb blind heated to 80 degrees by the sun can significantly affect the temperature of a 100,000 lb 75 degree house.
The sun's rays have far different effects on different materials. Stepping on grass vs stepping on blacktop is a good example of this. Your logic is proved wrong by the existence of the urban heat island effect. These heavy, sun-absorbing materials like concrete and steel make everything around them hotter. Your argument would have the grassy green areas at the same temperatures because they're simply releasing their heat right away.
In fact, this is such a factor here that it overrides whether or not something is inside vs outside of a house.
US Dept of Energy:
"Window awnings can reduce solar heat gain in the summer by up to 65% on south-facing windows and 77% on west-facing windows....
In cooling seasons, cellular shades can reduce unwanted solar heat through windows by up to 80%"
The reason for this is that cellular shades are made of such a light, heat-resistant material compared to an awning which must be durable and able to withstand wind, rain, and other elements. The awning will absorb the sunlight and slowly transfer the heat to your house which it is connected to. It is obviously still extremely effective, especially if is light colored or reflective.
I'm going to hop on Tyler's boat here. The thermal mass is completely irrelevant in scenario (though it plays a large role in home comfort for different reasons). The reason cellular shades work so well is that they 1) reflect some sunlight back out the window and 2) are insulated well enough to significantly increase the temperature between the shade and the wall, thereby allowing for decreased conductive/convective heat intake during the summer. If the cellular shade wasn't placed up against the window but was instead placed on the floor where the sun was shining, you'd find your house heating up just as fast as if that shade wasn't on the floor at all.
As to the comment on the urban heat island effect, it isn't the thermal mass (I'm not sure but I would think urban areas have less insulative properties than urban, thereby increasing effective thermal mass); on the contrary, from what I've read it's mostly due to decreased reflectivity, decreased evapotranspiration, decreased wind, and decreased solid angle exposure to the cold night sky.
You picked the wrong boat to hop on :)
Or the right one, given your wacky take on the UHI effect.
If you re-read my post, you'll find I don't place as much importance on thermal mass as you seem to argue. I use unscientific terms like "sun-absorbing" and "heat-resistant" which are the non-engineers version of "conductive" and "convective" as I am not an engineer.
However, thermal mass IS relevant in this scenario as it can act as a battery that gets filled up under the right conditions. If a given object readily absorbs the sun's heat energy, it's thermal mass matters. You might argue that regardless of whether or not an object has thermal mass, the heat will be transferred to the surrounding air, and you'd be right - but if windows are open and cross ventilation is in action, the rapidly released heat won't stick around like it would if a given object or material has significant thermal mass to store the heat.
Imagine your cellular shades NOT covering up a tile floor as the morning sun beat down on it. Then imagine 2pm rolls around and you close up your windows as the outdoor temp exceeds the indoor temp. The tile will have stored up all that heat that it otherwise wouldn't have. Yes, the cellular shade on the ground would have absorbed and released SOME (less as a tile floor is more conductive/convective than a cellular shade) heat, but that relatively small amount of heat would have been able to be ventilated during the cool morning hours. Now the tile floor will be releasing the heat into your house and you're not going to let it out at the risk of letting in a bunch of 95 degree air.
Regarding the urban heat island effect, you're right that it's not just one factor. But the major factor is that concrete and asphalt both absorb and STORE heat far more readily than vegetation.
How can I argue that it's the major factor? Not only is it the first factor mentioned in the wikipedia page, but the fact that the UHI effect is most dramatic at night demonstrates the how the thermal mass of concrete and asphalt stores up heat during the day and releases it at night. Not sure what you're saying about insulation as you used the word urban twice and I'm not sure which one was meant to be non-urban, but I don't think that argument would be sound if you meant urban areas have insulative properties. Pavement has none, and the insulation that buildings have are meant to keep the INSIDE a certain temperature.
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You picked the wrong boat to hop on :)
Or the right one, given your wacky take on the UHI effect.
If you re-read my post, you'll find I don't place as much importance on thermal mass as you seem to argue. I use unscientific terms like "sun-absorbing" and "heat-resistant" which are the non-engineers version of "conductive" and "convective" as I am not an engineer.
However, thermal mass IS relevant in this scenario as it can act as a battery that gets filled up under the right conditions. If a given object readily absorbs the sun's heat energy, it's thermal mass matters. You might argue that regardless of whether or not an object has thermal mass, the heat will be transferred to the surrounding air, and you'd be right - but if windows are open and cross ventilation is in action, the rapidly released heat won't stick around like it would if a given object or material has significant thermal mass to store the heat.
Imagine your cellular shades NOT covering up a tile floor as the morning sun beat down on it. Then imagine 2pm rolls around and you close up your windows as the outdoor temp exceeds the indoor temp. The tile will have stored up all that heat that it otherwise wouldn't have. Yes, the cellular shade on the ground would have absorbed and released SOME (less as a tile floor is more conductive/convective than a cellular shade) heat, but that relatively small amount of heat would have been able to be ventilated during the cool morning hours. Now the tile floor will be releasing the heat into your house and you're not going to let it out at the risk of letting in a bunch of 95 degree air.
Regarding the urban heat island effect, you're right that it's not just one factor. But the major factor is that concrete and asphalt both absorb and STORE heat far more readily than vegetation.
How can I argue that it's the major factor? Not only is it the first factor mentioned in the wikipedia page, but the fact that the UHI effect is most dramatic at night demonstrates the how the thermal mass of concrete and asphalt stores up heat during the day and releases it at night. Not sure what you're saying about insulation as you used the word urban twice and I'm not sure which one was meant to be non-urban, but I don't think that argument would be sound if you meant urban areas have insulative properties. Pavement has none, and the insulation that buildings have are meant to keep the INSIDE a certain temperature.
Let me add to my wacky ideas about the heat island effect by citing sources that don't stem from a Wikipedia article.
https://climate.ncsu.edu/edu/Vegetation (https://climate.ncsu.edu/edu/Vegetation): "With vegetation covering about 20% of our planet, it’s no surprise that plants affect climate. However, it is surprising how much plants affect weather. Plants process and release water vapor (necessary for cloud formation) and absorb and emit energy used to drive weather. Plants also produce their own micro-weather by controlling the humidity and temperature immediately surrounding their leaves through transpiration. Most plants and forest soils have a very low albedo, (about .03 to .20) and absorb a large amount of energy. However, plants don’t contribute to overall warming because the excess warmth is offset by evaporative cooling from transpiration."
Here's a couple more that are good reading material:
https://cdn.dcs.bluescope.com.au/download/sustainability-technical-bulletin-urban-heat-islands (https://cdn.dcs.bluescope.com.au/download/sustainability-technical-bulletin-urban-heat-islands)
http://profile.nus.edu.sg/fass/geomr/roth%20uhi%20hefd13.pdf (http://profile.nus.edu.sg/fass/geomr/roth%20uhi%20hefd13.pdf)
Long story short, thermal storage does and doesn't affect the UHI effect. It does in the sense that it delays the time that the UHI is most pronounced (as you mention), but it doesn't in that it is neutral on the energy balance (which is what I was trying to emphasize), because it absorbs as much energy as it releases. Figure 11.2 in that last link is really illustrative of this effect.
As to your comment on the air blowing out the heat in a house with a blind on the floor, yes, you'd be right, in that scenario thermal storage would make a difference. But it is kind of an odd-duck scenario, because nobody has blinds on the floor.
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You picked the wrong boat to hop on :)
Or the right one, given your wacky take on the UHI effect.
If you re-read my post, you'll find I don't place as much importance on thermal mass as you seem to argue. I use unscientific terms like "sun-absorbing" and "heat-resistant" which are the non-engineers version of "conductive" and "convective" as I am not an engineer.
However, thermal mass IS relevant in this scenario as it can act as a battery that gets filled up under the right conditions. If a given object readily absorbs the sun's heat energy, it's thermal mass matters. You might argue that regardless of whether or not an object has thermal mass, the heat will be transferred to the surrounding air, and you'd be right - but if windows are open and cross ventilation is in action, the rapidly released heat won't stick around like it would if a given object or material has significant thermal mass to store the heat.
Imagine your cellular shades NOT covering up a tile floor as the morning sun beat down on it. Then imagine 2pm rolls around and you close up your windows as the outdoor temp exceeds the indoor temp. The tile will have stored up all that heat that it otherwise wouldn't have. Yes, the cellular shade on the ground would have absorbed and released SOME (less as a tile floor is more conductive/convective than a cellular shade) heat, but that relatively small amount of heat would have been able to be ventilated during the cool morning hours. Now the tile floor will be releasing the heat into your house and you're not going to let it out at the risk of letting in a bunch of 95 degree air.
Regarding the urban heat island effect, you're right that it's not just one factor. But the major factor is that concrete and asphalt both absorb and STORE heat far more readily than vegetation.
How can I argue that it's the major factor? Not only is it the first factor mentioned in the wikipedia page, but the fact that the UHI effect is most dramatic at night demonstrates the how the thermal mass of concrete and asphalt stores up heat during the day and releases it at night. Not sure what you're saying about insulation as you used the word urban twice and I'm not sure which one was meant to be non-urban, but I don't think that argument would be sound if you meant urban areas have insulative properties. Pavement has none, and the insulation that buildings have are meant to keep the INSIDE a certain temperature.
Let me add to my wacky ideas about the heat island effect by citing sources that don't stem from a Wikipedia article.
https://climate.ncsu.edu/edu/Vegetation (https://climate.ncsu.edu/edu/Vegetation): "With vegetation covering about 20% of our planet, it’s no surprise that plants affect climate. However, it is surprising how much plants affect weather. Plants process and release water vapor (necessary for cloud formation) and absorb and emit energy used to drive weather. Plants also produce their own micro-weather by controlling the humidity and temperature immediately surrounding their leaves through transpiration. Most plants and forest soils have a very low albedo, (about .03 to .20) and absorb a large amount of energy. However, plants don’t contribute to overall warming because the excess warmth is offset by evaporative cooling from transpiration."
Here's a couple more that are good reading material:
https://cdn.dcs.bluescope.com.au/download/sustainability-technical-bulletin-urban-heat-islands (https://cdn.dcs.bluescope.com.au/download/sustainability-technical-bulletin-urban-heat-islands)
http://profile.nus.edu.sg/fass/geomr/roth%20uhi%20hefd13.pdf (http://profile.nus.edu.sg/fass/geomr/roth%20uhi%20hefd13.pdf)
Long story short, thermal storage does and doesn't affect the UHI effect. It does in the sense that it delays the time that the UHI is most pronounced (as you mention), but it doesn't in that it is neutral on the energy balance (which is what I was trying to emphasize), because it absorbs as much energy as it releases. Figure 11.2 in that last link is really illustrative of this effect.
As to your comment on the air blowing out the heat in a house with a blind on the floor, yes, you'd be right, in that scenario thermal storage would make a difference. But it is kind of an odd-duck scenario, because nobody has blinds on the floor.
I think we mostly agree on UHI's mechanics, but haven't established why we view it as a problem. If, for example, people being unable to sleep without using their ACs (which then in turn make the city even hotter) is one of the main problems, then thermal storage is indeed one of the main culprits of the UHI effect. If the main problem is that it's too hot in the morning, than thermal mass probably isn't to blame. However, if you meant what I think you meant about rural vs urban insulation, I stand by my claim that you have a wacky take on UHI...
I agree, a cellular shade left on the floor is kind of an odd duck scenario... Why'd you choose it?? :)
Regardless, I think we can apply the same mechanics without such a strange example. I, for example, have solar shades on my east windows. If I use them, the morning sun gets in my house but ultimately only directly heats up the shade and the window stool area. If I don't use them, it heats up my heavy oak floors all morning long and then when it's no longer shining on them, they continue to heat my house. And unfortunately I've closed the windows now because it's midday.
Anyways, I'm happy to spar until we're nitpicking to a seriously nerdy and overly contentious degree. Have we reached that point yet? Guess I'll keep going until it's glaringly obvious :)
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things to help keep the house cool:
1. Keep the blinds finished to keep off direct daylight.
2. Mop the floors with virus water.
3. Put a major can of ice before a fan and let the air blow over it.
4. can also use any dehumidifier which is best suited some are there https://dehumidifierslist.com/
4. During the evening, open a window toward one side of the house, and another where you need to be coolest. Put a fan in the far window so it hauls the warm let some circulation into. In the first part of the day, or when it begins getting warm, close the windows to keep the sight-seeing out.
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Anyways, I'm happy to spar until we're nitpicking to a seriously nerdy and overly contentious degree. Have we reached that point yet? Guess I'll keep going until it's glaringly obvious :)
Yep, we've reached that point, since I think we're fairly close to consensus, and to top it off we've veered a good way from the intent of this thread. (And for the record, urban areas are less insulative than rural. On reexamination that point didn't make much sense on my part.)
To jump on the actual topic, I open my windows at night and close them in the morning. Thermal shades work great, especially for windows where the sun shines through. Also, I don't turn on the air conditioning unless my house and outside temperatures are at least 84°F at bedtime; this is a little painful for the first few warm days each spring as my body acclimates, but after that it's extremely comfortable.
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My climate usually has high diurnal temperature variation, so we try to capture as much cool air as possible at night. A high velocity exhaust fan (whole house fan) is great for this. I have a 20" Air King window fan set to exhaust air in one room and windows open in every corner of the house to allow cool night air to enter. Our house also has limited solar gain through windows and a brick exterior that provides thermal mass. For the rare night that doesn't cool off, we have a window AC unit to run in the bedroom we sleep in (which also has the worst summer afternoon exposure).
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We put R49 batts in the attic and then added Gila brand thermal window tint (from Home Depot) to most all of our windows. It made a huge improvement to do the tint. It's not super dark but reflects 73% of the heat and 99% of UV rays. Made differece of 5-10* in most locations. Also put a light mesh "awning" over the porch and it was a 15* difference... I measured with my thermal laser tool from Harbor freight.
We also have thermal curtains to help cover windows and keep the cool/heat in depending on the weather. Also ceiling fans.
Yesterday it was 96*. A/C set to 76* inside... I only heard it kick on a couple of times to maintain the temp!!
Gila window film works really well. Installed it on a large kitchen window that was causing the room to become an oven in the afternoon. Not only was this terribly uncomfortable, but was also bad for food spoilage and made the fridge work too hard. After tinting some heat gets through but way less than before. Install was tedious and a little tricky, but it's a very inexpensive solution.
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Metal roofing makes a HUGE difference!
I don't have metal roof but my neighbour has it. His metal roof is black and my asphalt shingles are also black. Same sun orientation. Out of curiosity its 12:30 and checked with a IR thermometer the temperature of my roof and his.
It's sunny and 83F with a Real Feel of 91(and increasing) and my roof is at around 125-130F (facing west - just waint until the sun starts blasting at it more directly). My neigbour's roof on the other hand is at 85F! That's a HUGE difference! I never would have thought for the difference to be so great especially with the black color! That's a 40-45F difference!
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Metal roofing makes a HUGE difference!
I don't have metal roof but my neighbour has it. His metal roof is black and my asphalt shingles are also black. Same sun orientation. Out of curiosity its 12:30 and checked with a IR thermometer the temperature of my roof and his.
It's sunny and 83F with a Real Feel of 91(and increasing) and my roof is at around 125-130F (facing west - just waint until the sun starts blasting at it more directly). My neigbour's roof on the other hand is at 85F! That's a HUGE difference! I never would have thought for the difference to be so great especially with the black color! That's a 40-45F difference!
I hope you took the measurement of your neighbors roof while standing on it and from the same distance away. The maximum distance one can get an accurate measurement from an IR thermometer is 36 to 48 inches. Beyond that, those things aren't very accurate.
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I have a whole house fan and rarely use it. It draws in pollen and other dust particles. It really only helps cool the house down when the temps outside are colder. When the temps outside are hot all you do is draw in more hot air.
We have a window ac in the bedroom and a fan that blows across the bed. The dog insists on it!
We have a ductless ac unit in the living room that cools the upper floor nicely. We have a giant awning on our deck. Custom made by an awning company. I love it and it helps keep the house cool by shading the deck. We have one paddle fan in the dining room.
Insulated drapes help keep the heat out by closing them as the sun shines on them.
Yes, we have several months of higher electric cost but I want to sleep at night and be cool on a 80-99 degree day. My house gets hot and stays hot. NOPE, not gonna be miserable. I crank my ac on as soon as it gets hot/humid.
Window units are so cheap to buy! $99-$199 depending on BTU. The ductless unit was much more expensive and required professional installation. But it is cooling a lot of square feet.
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Hey y'all,
robartsd: I just bought the Airking 20" whole house fan (got in on Venting Direct's memorial day sale). My problem is that I have casement windows, so I don't have a seal around it, but I can probably rig up something to make that work. Even so, it does pull in some cool air through the bedroom windows in the evenings. It's really loud in my little house, though.
I got a general phone estimate for a mini split system: 8-9k! Yeah, nope. It could be that I could downsize to fewer inside units to get it to be cheaper, but geeze. I was expecting 4-5k for my small house. Hence the $130 Airking.
I have a metal roof, too! I hate to think how much worse it could be if those were asphalt shingles a few feet above my bedroom.
So far this year I can't complain. I've stayed fairly cool. But now it's June....
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I have a whole house fan and rarely use it. It draws in pollen and other dust particles. It really only helps cool the house down when the temps outside are colder. When the temps outside are hot all you do is draw in more hot air.
@Syonyk used a auto air filter with a housing he made out of cardboard and duct tape to create a filtered air intake for his previous house.
https://syonyk.blogspot.com/2015/12/a-post-summer-review-of-my-vent-fans.html (https://syonyk.blogspot.com/2015/12/a-post-summer-review-of-my-vent-fans.html)
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Cool showers at night, and going to bed with wet hair (especially for someone with thick, long hair) help tremendously. As does a damp wash cloth put in the freezer or a frozen water bottle wrapped in fabric or a sock.
I sleep very hot (and with my sensory issues, sleeping without covers is not an option). These things help a lot. But we also have a portable a/c unit in the bedroom which we can use when it's extra hot or humid. Cheaper to cool our one room than the whole house.
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@Syonyk used a auto air filter with a housing he made out of cardboard and duct tape to create a filtered air intake for his previous house.
https://syonyk.blogspot.com/2015/12/a-post-summer-review-of-my-vent-fans.html (https://syonyk.blogspot.com/2015/12/a-post-summer-review-of-my-vent-fans.html)
I'm still using the fans. I don't bother with a filtered intake anymore - we moved, and have a screened window that will keep bugs out when we open it.
They're still quite the useful air movers!
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Metal roofing makes a HUGE difference!
I don't have metal roof but my neighbour has it. His metal roof is black and my asphalt shingles are also black. Same sun orientation. Out of curiosity its 12:30 and checked with a IR thermometer the temperature of my roof and his.
It's sunny and 83F with a Real Feel of 91(and increasing) and my roof is at around 125-130F (facing west - just waint until the sun starts blasting at it more directly). My neigbour's roof on the other hand is at 85F! That's a HUGE difference! I never would have thought for the difference to be so great especially with the black color! That's a 40-45F difference!
I hope you took the measurement of your neighbors roof while standing on it and from the same distance away. The maximum distance one can get an accurate measurement from an IR thermometer is 36 to 48 inches. Beyond that, those things aren't very accurate.
Yes, at end of next day I even went to his attic. My attic inside was at 140 degrees while his attic was sitting at 95 or so
I also have the airking 20". Got it last year and I was torn between the 16 and 20 inch version... god, the 20" is a monster! It caught me off guard of how big it is. Anyhow, I mount it in a side window in my office, which is very inconspicuous and I don't care really. I have the fan on Sonoff wifi plugs and have some IFTT conditions in them. I turn them manually at night if temperature is below than inside, and I have auto conditions to turn them around 4-5am if temps are low. Around 5am is when temps are lowest so we want to intake as much air as possible of those cold temperatures in order to "reset" the house for the coming hot day. It helps if its going to be a really hot day.
Just this weekend on Saturday, it was 90s outside, the house finished the day at around 74F without using AC. We opened the windows at night to cool the house and it decreased to 72F or so. However at 5-6am, once the fan kicked in for 2 hours, it got the house to around 63F in the morning. At 4Pm during 90 degree weather, the house was still at a very cool 70F. Im sure if I didn't have or use the airking fan, the AC would have kicked in probably since there wasn't as much buffer.
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I don't know about how feasible this idea is, but grape vines grown over a pergola can be a great solution to this type of problem. They provide shade in summer, and let light through in winter when they drop their leaves. The also provide fruit, and as they are plants, evapotranspirate moisture into the local environment, changing the "feel" of the air. This may be a solution that takes a couple of years, but vines grow fairly quickly.
They will require maintenance, but can also add significant beauty to a lot of houses.
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I don't know about how feasible this idea is, but grape vines grown over a pergola can be a great solution to this type of problem. They provide shade in summer, and let light through in winter when they drop their leaves. The also provide fruit, and as they are plants, evapotranspirate moisture into the local environment, changing the "feel" of the air. This may be a solution that takes a couple of years, but vines grow fairly quickly.
They will require maintenance, but can also add significant beauty to a lot of houses.
The only drawback of this solution is that the fruit draws bees and yellow jackets. Not to mention birds swooping down to get some fruit and probably other wild life like deer. Maybe some non fruit bearing ivy vines would work.
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Metal roofing makes a HUGE difference!
Yes, at end of next day I even went to his attic. My attic inside was at 140 degrees while his attic was sitting at 95 or so
I also have the airking 20". ... I have the fan on Sonoff wifi plugs and have some IFTT conditions in them. I turn them manually at night if temperature is below than inside, and I have auto conditions to turn them around 4-5am if temps are low.
I'm guessing that the attic is also very well vented.
The only thing that disappoints me about the AirKing is that large gaps between the main housing and the side panels that adjust for width as well as the gap between the fan housing and the window. The window mine is mounted in does not have a insect screen, so I have made no attempts to automate yet - as I have to open and close the window manually when turning the fan on/off. I fear if I just put a screen in, a significant amount of the air will blowback through these gaps. I might try to find some rubber weatherstripping sweeps that can cover these gaps in the future.
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Another bonus for whole house fan. We installed this guy and run it once a day or whenever we need to clear the "food smell" out of the house. https://www.amazon.com/QuietCool-QC-CL-3100-Original-Classic/dp/B00JC5M138/ref=asc_df_B00K0Q4W0I/?tag=hyprod-20&linkCode=df0&hvadid=167116234959&hvpos=1o2&hvnetw=g&hvrand=673085712814267309&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031625&hvtargid=pla-308511245970&th=1
We have yet to turn out A/C on this year.
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We just installed a whole house fan recently. We have only had a handful of hot days so far this year, but I have been very impressed. The main benefit is that by running it at night and in the early morning we start the day with a very cool house. By evening it starts feeling too warm right around the time that it makes sense to open the windows and turn the fan back on.
Like the poster above me we got a Quiet Cool as well. It is much quieter than the older style whole house fan my parents' used to have.
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Wholehouse fans are excellent.
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do u guys keep lots of potted plants?
i keep a few big leafy potted plants and i find them cooling down the home remarkably. i can honestly feel the slightly cooler air around the plants.
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do u guys keep lots of potted plants?
i keep a few big leafy potted plants and i find them cooling down the home remarkably. i can honestly feel the slightly cooler air around the plants.
I could see how a big pot of soil could help by adding thermal mass to your house, but how does a plant cool the air?
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First of all, look at how you can avoid adding heat to your house. Some ideas:
1) Hook up a gas grill to your natural gas supply and cook outside as much as possible.
2) Line dry clothing.
3) Shorten the long steamy showers and try to use cooler water.
4) Of course you don’t use incandescent/halogen bulbs for ANYTHING, right?
Second, if your attic is under-ventilated like most attics (very safe to assume it is), a quick weekend project to add a turbine and some soffit vents could drop it 10 degrees F in the summer, which will make a huge difference for less than $100 in materials. 140 degrees F in the attic on a 100 degree day is too hot. Aim for 120 F.
Third, there is no justification for wearing jeans, hats, leather shoes/boots, or long sleeves around the house and then turning on the AC because you’re hot. Hell, I usually skip the socks and just wear sandals June-July.
Fourth, if you have AC, at least maintain it. Change the filter regularly and clean the coils inside and out each summer. Also clean the coils on your fridge so it can get air flow and run efficiently.
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I could see how a big pot of soil could help by adding thermal mass to your house, but how does a plant cool the air?
Trans-evaporation - basically the same way a swamp cooler does but on a smaller/slower scale. More useful in dry climates than in humid ones.
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I could see how a big pot of soil could help by adding thermal mass to your house, but how does a plant cool the air?
Trans-evaporation - basically the same way a swamp cooler does but on a smaller/slower scale. More useful in dry climates than in humid ones.
I was gonna say . . . jungles have some of the highest ratio of vegetation to other stuff in the world, and they're not typically known for being cold. :P
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Don't forget that plants convert solar energy into a storage form (glucose). I'm currently going through the same decision process as OP and leaning toward a trellis and vines (my window is not as high).
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At my home I've only did the plinths.Everything else was done by qualified masters
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Our house was built with a large overhang on the south side over windows. It reduces sun penetration into the house in the summer when the sun is high in the sky but allows it in the winter when it's lower in the sky.
When we visit the Caribbean, we've noticed that most houses have louvers outside of the windows. This is the most efficient place for them as opposed to interior treatments as it prevents sunlight from coming into the house in the first place. Of course, most of those houses don't have windows closed up. They're either open or have screens.
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Our house was built with a large overhang on the south side over windows. It reduces sun penetration into the house in the summer when the sun is high in the sky but allows it in the winter when it's lower in the sky.
When we visit the Caribbean, we've noticed that most houses have louvers outside of the windows. This is the most efficient place for them as opposed to interior treatments as it prevents sunlight from coming into the house in the first place. Of course, most of those houses don't have windows closed up. They're either open or have screens.
This. I never understood the concept of fake shutters in the US houses. It adds nothing. South of Spain and south of Portugal where temperatures get quite hot 100-110F easily, not only houses are painted white to reflect heat gain but also window shutters that close. Make a big difference to the point you can even keep the window open and just have the shutters closed and yet is still comfortable inside.
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I have a bonus room over the uninsulated garage which both face west. The bonus room was getting very hot.
I ended up taping up vertical strips of aluminum foil - overlapping them by an inch or so - over the bonus room window and was shocked at how much it reduced the heat gain. I think my A/C bill will be cut in half.
Not the most stylish-looking, but it's behind curtains, so it's not visible at the moment. Also very very very cheap to try.
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My top floor has a sliding glass door out to a roof deck on one side and a big window on the west side. It gets really hot up there.
1. Thermal curtains on sliding glass door. Keep shut when sun is shining in.
2. West window: blackout cellular shade + Solar shade (one blocks all light and the other lets some through when I want it)
3. Retractable awning over the roof deck -- keeps deck cooler and also doesn't let the light/heat get to that side of the house & the glass door. Awning has a wind sensor and retracts automatically in wind.
4. Solar panels on roof -- mine didn't cost me a penny. I don't know your location, but please check to see if any of these free offers exist in your area. In addition to the energy production value, they also provide shade for my roof, which is a huge benefit for cooling.
My neighbors added trellis + potted vines that grow in the spring/summer up against the wall surrounding the glass door -- makes a huge difference just to shade that sliver of wall. I'm going to add this to my list for next year.
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I ended up taping up vertical strips of aluminum foil - overlapping them by an inch or so - over the bonus room window and was shocked at how much it reduced the heat gain. I think my A/C bill will be cut in half.
It's probably OK with just aluminum foil, but make sure you don't get the vinyl window frames too hot - they can warp if you make a greenhouse. I insulated some windows on my office shed and rather cooked a frame that way - I had to put a shutter outside to block the sun.
4. Solar panels on roof -- mine didn't cost me a penny. I don't know your location, but please check to see if any of these free offers exist in your area. In addition to the energy production value, they also provide shade for my roof, which is a huge benefit for cooling.
Most of the "free" panel deals I've seen are a crap deal for the homeowner, make the house ~impossible to sell, and you're paying regardless of what the panels do. They're a marginal deal compared to full on expensive solar installers with their tricksy financing packages, but a crap deal compared to what you can actually do in most areas.
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Most of the "free" panel deals I've seen are a crap deal for the homeowner, make the house ~impossible to sell, and you're paying regardless of what the panels do. They're a marginal deal compared to full on expensive solar installers with their tricksy financing packages, but a crap deal compared to what you can actually do in most areas.
This is true, many "free" deals might actually mean leasing or can be bad deals in other ways. But in Washington DC, the solar credits are so rewarding that they entice solar vendors to trade free materials + labor in exchange for the potential to make more back by selling Solar Renewable Energy Credits. That's why I suggested checking the incentives in the local area. For me, I could probably make more by keeping the SRECs and selling them on the open market over the next 6-9 years, but this way, my risk was zero and by month 4, my ROI was already over 100%. I own the panels and can remove them whenever I want to.
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When we replace our roof, we'll be using plywood with a radiant barrier. In the meantime, DH went into the attic and installed barrier to the existing interior. Not sure how much difference this will make but we'll take it.
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We put R49 batts in the attic and then added Gila brand thermal window tint (from Home Depot) to most all of our windows. It made a huge improvement to do the tint. It's not super dark but reflects 73% of the heat and 99% of UV rays. Made differece of 5-10* in most locations. Also put a light mesh "awning" over the porch and it was a 15* difference... I measured with my thermal laser tool from Harbor freight.
We also have thermal curtains to help cover windows and keep the cool/heat in depending on the weather. Also ceiling fans.
Yesterday it was 96*. A/C set to 76* inside... I only heard it kick on a couple of times to maintain the temp!!
Gila window film works really well. Installed it on a large kitchen window that was causing the room to become an oven in the afternoon. Not only was this terribly uncomfortable, but was also bad for food spoilage and made the fridge work too hard. After tinting some heat gets through but way less than before. Install was tedious and a little tricky, but it's a very inexpensive solution.
Good to hear that about the window film, I just bought some! I've got one room which is becoming an oven in the afternoons, and then it's heating up the rest of the floor too. Hoping that the film will interrupt the process. If it works, I'll consider other rooms which might benefit.
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Good to hear that about the window film, I just bought some! I've got one room which is becoming an oven in the afternoons, and then it's heating up the rest of the floor too. Hoping that the film will interrupt the process. If it works, I'll consider other rooms which might benefit.
Make sure the windows are super clean, and have enough extra around the edges that your fingerprints are on the parts that get trimmed off. Use lots of spray on the film and the window, which gives you time to work/move the film as needed, and be careful to squeegee all the air pockets out. At first it will look a little off with little blisters of water bubbles in the film that give it a funny texture...don't worry about it, within about a week these water blisters will dry out and the film will cure.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Get a few high power portable fans. Position them next to your windows, Open the windows before you go to bed and blast as much hot air out/cool air in. Close 'em up and do it again in the morning. That's about the best you can do.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Get a few high power portable fans. Position them next to your windows, Open the windows before you go to bed and blast as much hot air out/cool air in. Close 'em up and do it again in the morning. That's about the best you can do.
I can't leave the windows open overnight due to the rain. That's the problem.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Buy a window ac unit, put it in your window, set it and forget it. Nice cool room!
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Get a few high power portable fans. Position them next to your windows, Open the windows before you go to bed and blast as much hot air out/cool air in. Close 'em up and do it again in the morning. That's about the best you can do.
I can't leave the windows open overnight due to the rain. That's the problem.
Yes, that's where the fans come in. You open the windows and turn the fans on while you're awake in the evening. Close them before bed. Open them and turn the fans on in the morning. Close them before you leave for work.
It's not as good as leaving the windows open overnight, but you can clear out most of the warm air from your home and pump in a lot of cool stuff.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
This is correct. Leaving windows open will cause your stuff to grow mold in places with high humidity (hello from Arkansas). Opening a window to cool off might work great in Colorado or Southern California, but it will cause problems in 80% humidity.
On the flip side, take steps to reduce the amount of humidity in your house. This mainly means shorter cooler showers with the exhaust fan on. I’ve also considered running a hose to drain my refrigerator condensation outside the house.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Does your house come with sufficient eaves? My experience is that the rainier parts of the U.S. have low correlation with the windier parts of the U.S., so eaves are generally sufficient to allow for open windows at night without the threat of water intrusion. (Partial source: Growing up in Miami without AC, in which open windows were a necessity.)
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Does your house come with sufficient eaves? My experience is that the rainier parts of the U.S. have low correlation with the windier parts of the U.S., so eaves are generally sufficient to allow for open windows at night without the threat of water intrusion. (Partial source: Growing up in Miami without AC, in which open windows were a necessity.)
??? Doesn't Miami get heavy wind and rain at the same time? Eaves are good for just gentle rain, but wind and rain together are definitely a thing here. It's not uncommon to have downpours paired with 40 mph wind here. They also can come up quite unexpectedly. Having your window open even just a small crack would result in the whole room being wet.
You could watch the weather forecast because there are plenty of nights where the forecast is for no storms. I should ask my grandmother what they did to keep rain from coming in when they had the windows open.
I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Get a few high power portable fans. Position them next to your windows, Open the windows before you go to bed and blast as much hot air out/cool air in. Close 'em up and do it again in the morning. That's about the best you can do.
I can't leave the windows open overnight due to the rain. That's the problem.
Yes, that's where the fans come in. You open the windows and turn the fans on while you're awake in the evening. Close them before bed. Open them and turn the fans on in the morning. Close them before you leave for work.
It's not as good as leaving the windows open overnight, but you can clear out most of the warm air from your home and pump in a lot of cool stuff.
Cool stuff? Bless your little Canadian heart.
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??? Doesn't Miami get heavy wind and rain at the same time? Eaves are good for just gentle rain, but wind and rain together are definitely a thing here. It's not uncommon to have downpours paired with 40 mph wind here. They also can come up quite unexpectedly. Having your window open even just a small crack would result in the whole room being wet.
Certainly in a hurricane, but does heavy rain and wind come unexpectedly (no storm warning)?
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Those of you with the ductless mini-splits, do you like them, especially compared to a central AC system? Did you have them installed yourself, and were they expensive?
We're moving to a new house with no central AC. It has baseboard heat, so there's no existing ductwork to add an AC unit to, either. Almost all of the rooms have ceiling fans, but there are also large windows on the east, south, and west side of the house. There are SOME trees on the south and west side, but we're looking at options if August is ridiculously hot.
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Those of you with the ductless mini-splits, do you like them, especially compared to a central AC system? Did you have them installed yourself, and were they expensive?
We're moving to a new house with no central AC. It has baseboard heat, so there's no existing ductwork to add an AC unit to, either. Almost all of the rooms have ceiling fans, but there are also large windows on the east, south, and west side of the house. There are SOME trees on the south and west side, but we're looking at options if August is ridiculously hot.
For probably 25 years we had an in wall ac unit to cool our upper floor. It was around 24,000 BTU. We got a ductless unit to replace it and it is 24,000 BTU as well. It is very quit compared to the wall unit we had. The original wall unit was a work horse and never failed in all those years. The new unit crapped out during the second year. It was under warranty for parts but we had to pay for service. It was fixed and is wonderful. It cools the bulk of our first floor. We have a window unit in our bedroom window. I love the ductless unit. Don't let them talk you into less BTU's. We had the 24,000 BTU unit and it was an ass kicker. The ac company tried to talk us into an 18,000 BTU unit and we said no way! I don't want a unit that will limp during cooling season, I want it to do the job and do it well.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Does your house come with sufficient eaves? My experience is that the rainier parts of the U.S. have low correlation with the windier parts of the U.S., so eaves are generally sufficient to allow for open windows at night without the threat of water intrusion. (Partial source: Growing up in Miami without AC, in which open windows were a necessity.)
??? Doesn't Miami get heavy wind and rain at the same time? Eaves are good for just gentle rain, but wind and rain together are definitely a thing here. It's not uncommon to have downpours paired with 40 mph wind here. They also can come up quite unexpectedly. Having your window open even just a small crack would result in the whole room being wet.
You could watch the weather forecast because there are plenty of nights where the forecast is for no storms. I should ask my grandmother what they did to keep rain from coming in when they had the windows open.
From my recollection living in Florida for my first 25 years, the heavy downpours tended to happen almost exclusively in the late afternoons or early evenings. (I could have set my watch to the onset of rain during Gainesville summers.) That is my anecdote, and admittedly it is outdated by a dozen or so years. The climate maps for wind would seem to back up my anecdote when it comes to average wind speed in the southeast: https://www.nrel.gov/gis/images/30m_US_Wind.jpg (https://www.nrel.gov/gis/images/30m_US_Wind.jpg).
I think one of the major downsides to AC has been the huge reduction in windows for modern construction. Our house in Miami was from the 1950's, and had large windows in every room, plus the 'Florida room' which had functional opening windows all the way around.
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??? Doesn't Miami get heavy wind and rain at the same time? Eaves are good for just gentle rain, but wind and rain together are definitely a thing here. It's not uncommon to have downpours paired with 40 mph wind here. They also can come up quite unexpectedly. Having your window open even just a small crack would result in the whole room being wet.
Certainly in a hurricane, but does heavy rain and wind come unexpectedly (no storm warning)?
Yes it does quite a bit. There is generally a certain amount of warning you would get if you were awake, but at night when you're asleep it could easily catch you off guard. Usually the weather forecast can tell you the chances, but when the forecast is 20% it can be really hit and miss. They're generally more common in the afternoon, but there are plenty at night. We've been having a lot of them here lately. Just last week we had a random storm come through with a lot of wind and rain at 1:30 in the morning.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Does your house come with sufficient eaves? My experience is that the rainier parts of the U.S. have low correlation with the windier parts of the U.S., so eaves are generally sufficient to allow for open windows at night without the threat of water intrusion. (Partial source: Growing up in Miami without AC, in which open windows were a necessity.)
No. We have basically no eaves. Water definitely comes in when it rains. We learned that very quickly our second night in the home.
As it turns out, water also comes in to the basement--6"!!!!--when it rains a lot.
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I'm new to a humid, rainy climate. How on earth does one do it? I can't leave the windows open at night--not even cracked, because storms pop up suddenly and everything gets drenched. (Ask me how I know.) But I'm losing all that cooler night air with my windows shut tight. Am I missing something? (And yes, we do have frequent, fairly sudden rain storms. I can open a few windows when we are home and awake because I can shut them quickly and mop up any water on the wood floors that may sneak in before it has time to sit. But once we go to bed, it seems I have to close everything up.
Does your house come with sufficient eaves? My experience is that the rainier parts of the U.S. have low correlation with the windier parts of the U.S., so eaves are generally sufficient to allow for open windows at night without the threat of water intrusion. (Partial source: Growing up in Miami without AC, in which open windows were a necessity.)
No. We have basically no eaves. Water definitely comes in when it rains. We learned that very quickly our second night in the home.
As it turns out, water also comes in to the basement--6"!!!!--when it rains a lot.
You can put awnings over the windows you benefit most from keeping open.
If they are double hung windows, you can open them from the top instead and they will be that much less likely to allow water in.
Bonus is that they'll keep heat out too esp. on the west and south side of the house (assuming you're in the northern hemisphere)
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As it turns out, water also comes in to the basement--6"!!!!--when it rains a lot.
What you're referring to as a basement sounds like it may actually be an old well. :P
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As it turns out, water also comes in to the basement--6"!!!!--when it rains a lot.
What you're referring to as a basement sounds like it may actually be an old well. :P
Or an indoor swimming pool.
It hasn't been a fun couple of days around here!
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As it turns out, water also comes in to the basement--6"!!!!--when it rains a lot.
What you're referring to as a basement sounds like it may actually be an old well. :P
Or an indoor swimming pool.
It hasn't been a fun couple of days around here!
Throw in some pool noodles. Some people pay a lot of money for what you've got for free!
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Basements are fairly uncommon in this area for that very reason.
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Didn't want to make a new topic for this but hopefully don't mind me piggybacking:
I live in New England where the summer months are generally in the 80's and the nights tend to be in the 60's or sometimes lower. I tend to open the windows when it's in the 70's with about 40% humidity, but once the temperature drops to the 60's or lower, the humidity seems to rise to the 80-90%.
I know high humidity isn't good for a home, but also read 80% humidity in 90 degree weather isn't the same as 80% humidity in 60 degree weather.
Can anyone help with this? Should I just leave the windows open briefly or should I be ok leaving them open in the night if the temperature is in the 60's but humidity is 80-90%?
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Didn't want to make a new topic for this but hopefully don't mind me piggybacking:
I live in New England where the summer months are generally in the 80's and the nights tend to be in the 60's or sometimes lower. I tend to open the windows when it's in the 70's with about 40% humidity, but once the temperature drops to the 60's or lower, the humidity seems to rise to the 80-90%.
I know high humidity isn't good for a home, but also read 80% humidity in 90 degree weather isn't the same as 80% humidity in 60 degree weather.
Can anyone help with this? Should I just leave the windows open briefly or should I be ok leaving them open in the night if the temperature is in the 60's but humidity is 80-90%?
Relative humidity is truly a poor metric that somehow got elevated into common parlance. The problem with relative humidity is that it is the percentage of water vapor in the air relative to the amount of water that can be held in the air at that temperature, which wouldn't necessarily be a problem except that the amount of water vapor air can hold is heavily dependent on temperature. As can be seen from the chart on this page (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html)), for every 20°F increase in temperature, the amount of water the air can hold just about doubles. Put another way, if the temperature drops 20°F and the amount of vapor in the air stays constant, your relative humidity will double. Needless to say, relative humidity levels fluctuate significantly on a diurnal basis, and it makes for a ton of unnecessary confusion.
A much better metric to use, that is also widely reported, is dew point. This is the temperature at which water will begin condensing out of the air as dew. This number is independent of temperature and stays constant with the amount of water vapor that is present in the air.
All of that being said, I personally wouldn't worry about the humidity if your outside temperature is in the 60's and you are comfortable with the ambient temperature throughout the day (and if you aren't comfortable, your A/C will take out the water vapor if you decide to run it).
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Our master bedroom has an odd little area. It's one small (3-4 inches) step up and is an open, mostly useless area roughly 5x5 with a closet (not walk-in) on either side. It also has two skylights over it and three skinny windows along the back. (Old house, many changes and additions, so things are sometimes odd.) I just installed heavy velvet blackout curtains last night to separate that area from the rest of the room. They weren't especially cheap. But this afternoon (day 1 of the curtains) I could feel a significant difference. With the a/c off upstairs during the day, it's usually very hot in our bedroom by afternoon. With those curtains closed, the hot air from the skylights and windows stayed inside the curtained off area, so the bedroom didn't heat up nearly as much. I spent a fair amount on the curtains but think this is going to pay for itself rather quickly. We run a portable a/c in the bedroom at night (I sleep hot, but don't want to cool the entire level all night since we are the only two people living here). I'm quite certain it is going to run far less, with a smaller space to cool and a lower starting temp when we turn it on.
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Our energy usage decreased by 6% this summer, despite high temperatures, and the only changes we made were pinning thermal blackout liners to the backs of all our curtains and replacing ancient, flimsy basement windows with glass block.
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Didn't want to make a new topic for this but hopefully don't mind me piggybacking:
I live in New England where the summer months are generally in the 80's and the nights tend to be in the 60's or sometimes lower. I tend to open the windows when it's in the 70's with about 40% humidity, but once the temperature drops to the 60's or lower, the humidity seems to rise to the 80-90%.
I know high humidity isn't good for a home, but also read 80% humidity in 90 degree weather isn't the same as 80% humidity in 60 degree weather.
Can anyone help with this? Should I just leave the windows open briefly or should I be ok leaving them open in the night if the temperature is in the 60's but humidity is 80-90%?
Relative humidity is truly a poor metric that somehow got elevated into common parlance. The problem with relative humidity is that it is the percentage of water vapor in the air relative to the amount of water that can be held in the air at that temperature, which wouldn't necessarily be a problem except that the amount of water vapor air can hold is heavily dependent on temperature. As can be seen from the chart on this page (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html)), for every 20°F increase in temperature, the amount of water the air can hold just about doubles. Put another way, if the temperature drops 20°F and the amount of vapor in the air stays constant, your relative humidity will double. Needless to say, relative humidity levels fluctuate significantly on a diurnal basis, and it makes for a ton of unnecessary confusion.
A much better metric to use, that is also widely reported, is dew point. This is the temperature at which water will begin condensing out of the air as dew. This number is independent of temperature and stays constant with the amount of water vapor that is present in the air.
All of that being said, I personally wouldn't worry about the humidity if your outside temperature is in the 60's and you are comfortable with the ambient temperature throughout the day (and if you aren't comfortable, your A/C will take out the water vapor if you decide to run it).
If dew point is independent of temperature then how come in the fall when outdoor temperatures are between 8 to 15 degrees and the windows/doors to the house are always shut there's never condensation on the windows? In the winter when temperatures are from -5 to -20 threre's always condensation on the windows. If anything, the humidity is lower in our house in the winter.
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Didn't want to make a new topic for this but hopefully don't mind me piggybacking:
I live in New England where the summer months are generally in the 80's and the nights tend to be in the 60's or sometimes lower. I tend to open the windows when it's in the 70's with about 40% humidity, but once the temperature drops to the 60's or lower, the humidity seems to rise to the 80-90%.
I know high humidity isn't good for a home, but also read 80% humidity in 90 degree weather isn't the same as 80% humidity in 60 degree weather.
Can anyone help with this? Should I just leave the windows open briefly or should I be ok leaving them open in the night if the temperature is in the 60's but humidity is 80-90%?
Relative humidity is truly a poor metric that somehow got elevated into common parlance. The problem with relative humidity is that it is the percentage of water vapor in the air relative to the amount of water that can be held in the air at that temperature, which wouldn't necessarily be a problem except that the amount of water vapor air can hold is heavily dependent on temperature. As can be seen from the chart on this page (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html)), for every 20°F increase in temperature, the amount of water the air can hold just about doubles. Put another way, if the temperature drops 20°F and the amount of vapor in the air stays constant, your relative humidity will double. Needless to say, relative humidity levels fluctuate significantly on a diurnal basis, and it makes for a ton of unnecessary confusion.
A much better metric to use, that is also widely reported, is dew point. This is the temperature at which water will begin condensing out of the air as dew. This number is independent of temperature and stays constant with the amount of water vapor that is present in the air.
All of that being said, I personally wouldn't worry about the humidity if your outside temperature is in the 60's and you are comfortable with the ambient temperature throughout the day (and if you aren't comfortable, your A/C will take out the water vapor if you decide to run it).
If dew point is independent of temperature then how come in the fall when outdoor temperatures are between 8 to 15 degrees and the windows/doors to the house are always shut there's never condensation on the windows? In the winter when temperatures are from -5 to -20 threre's always condensation on the windows. If anything, the humidity is lower in our house in the winter.
Here's an example to help illustrate the idea: Let's assume you have enough water vapor inside your house so that the dew point is 0°C (this would work out to 3.77 g of water per kilogram of air). Let's also assume negligible insulation from your windows (not an accurate assumption, but gets the point across). If the outside air temperature stays above 0°C, the inside air in contact with your windows cannot condensate since it is above the dew point, and the dew point will remain constant. However, if the outside air drops below 0°C, the inside air in contact with the windows will drop below the dew point and water vapor must condensate on the windows (and the dew point of that air in contact with the windows must drop as well since the air is losing water vapor). So to answer your question, the humidity is lower in the house in the winter directly as a result of the water vapor in the air forming condensate at cold interfaces (and due to air exchanges with the low humidity outside air).
(On a side note, air conditioning sucks water vapor out of the air by lowering the temperature of the air by the coils to a very low temperature prior to blowing it back through the house. So even if somebody sets the thermostat to a temperature above the dew point, the air that is being chilled will be at a much lower temperature and the resulting dew point (aka humidity) in the house will drop accordingly.)
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Didn't want to make a new topic for this but hopefully don't mind me piggybacking:
I live in New England where the summer months are generally in the 80's and the nights tend to be in the 60's or sometimes lower. I tend to open the windows when it's in the 70's with about 40% humidity, but once the temperature drops to the 60's or lower, the humidity seems to rise to the 80-90%.
I know high humidity isn't good for a home, but also read 80% humidity in 90 degree weather isn't the same as 80% humidity in 60 degree weather.
Can anyone help with this? Should I just leave the windows open briefly or should I be ok leaving them open in the night if the temperature is in the 60's but humidity is 80-90%?
Relative humidity is truly a poor metric that somehow got elevated into common parlance. The problem with relative humidity is that it is the percentage of water vapor in the air relative to the amount of water that can be held in the air at that temperature, which wouldn't necessarily be a problem except that the amount of water vapor air can hold is heavily dependent on temperature. As can be seen from the chart on this page (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html (https://www.engineeringtoolbox.com/water-vapor-air-d_854.html)), for every 20°F increase in temperature, the amount of water the air can hold just about doubles. Put another way, if the temperature drops 20°F and the amount of vapor in the air stays constant, your relative humidity will double. Needless to say, relative humidity levels fluctuate significantly on a diurnal basis, and it makes for a ton of unnecessary confusion.
A much better metric to use, that is also widely reported, is dew point. This is the temperature at which water will begin condensing out of the air as dew. This number is independent of temperature and stays constant with the amount of water vapor that is present in the air.
All of that being said, I personally wouldn't worry about the humidity if your outside temperature is in the 60's and you are comfortable with the ambient temperature throughout the day (and if you aren't comfortable, your A/C will take out the water vapor if you decide to run it).
If dew point is independent of temperature then how come in the fall when outdoor temperatures are between 8 to 15 degrees and the windows/doors to the house are always shut there's never condensation on the windows? In the winter when temperatures are from -5 to -20 threre's always condensation on the windows. If anything, the humidity is lower in our house in the winter.
Here's an example to help illustrate the idea: Let's assume you have enough water vapor inside your house so that the dew point is 0°C (this would work out to 3.77 g of water per kilogram of air). Let's also assume negligible insulation from your windows (not an accurate assumption, but gets the point across). If the outside air temperature stays above 0°C, the inside air in contact with your windows cannot condensate since it is above the dew point, and the dew point will remain constant. However, if the outside air drops below 0°C, the inside air in contact with the windows will drop below the dew point and water vapor must condensate on the windows (and the dew point of that air in contact with the windows must drop as well since the air is losing water vapor). So to answer your question, the humidity is lower in the house in the winter directly as a result of the water vapor in the air forming condensate at cold interfaces (and due to air exchanges with the low humidity outside air).
(On a side note, air conditioning sucks water vapor out of the air by lowering the temperature of the air by the coils to a very low temperature prior to blowing it back through the house. So even if somebody sets the thermostat to a temperature above the dew point, the air that is being chilled will be at a much lower temperature and the resulting dew point (aka humidity) in the house will drop accordingly.)
I still don't get it. We keep the indoor temperature at 17 degrees in the winter . . . and get condensation on the windows. if we increase the temperature indoors to 23 degrees (because guests are staying over or something) the condensation on the windows disappears. The air exchange should be happening more quickly with the greater temperature difference. Why does the condensation go away?
I feel like dew point must therefore be temperature dependent.
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I still don't get it. We keep the indoor temperature at 17 degrees in the winter . . . and get condensation on the windows. if we increase the temperature indoors to 23 degrees (because guests are staying over or something) the condensation on the windows disappears. The air exchange should be happening more quickly with the greater temperature difference. Why does the condensation go away?
I feel like dew point must therefore be temperature dependent.
I simplified my earlier analysis by using the assumption of "negligible insulation at the windows". In reality, all windows have some insulation, so that the air temperature at the interface of the window is some fraction of the way between the air temperature inside the house and the air temperature outside the house. Let's use 50%, and assume the outside temperature is 5°C. So when your house is 17°C, the temperature at the air-window interface is 11°C, whereas if the indoor temperature is 23°C, the temperature at the air-window interface will be 14°C. A 3°C delta is roughly equivalent to 25% more water vapor that could be held in the air, which must have been enough to not form condensate.
By definition, dew point is the air temperature at which water will condensate given the amount of water in the air. It is only dependent on the amount of water vapor in the air, and nothing else.
ETA: That last statement isn't true. Dew point is also a function of pressure.
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Thank you @Boofinator for that description. That may have been the most helpful bit of information I read so far on this issue although I also am still a bit confused.
Not to over simplify, but it sounds like as long as the dew point is similar from outside to inside and condensation won't form on the windows, then I should be ok to leave them open and not worry about too much moisture coming inside the home?
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Thank you @Boofinator for that description. That may have been the most helpful bit of information I read so far on this issue although I also am still a bit confused.
Not to over simplify, but it sounds like as long as the dew point is similar from outside to inside and condensation won't form on the windows, then I should be ok to leave them open and not worry about too much moisture coming inside the home?
Yes, you are correct: if the dew point is the same inside and out, then you need not worry at all about moisture coming in. Things get a little tricky during the summer months if the outside dew point is higher than the inside dew point. Not to get too nerdy here, but scientists and engineers separate heat into two categories: sensible and latent. Sensible heat relates to the heat required to change the temperature, and latent heat relates to heat that changes some property other than the temperature (for example, humidity). So in the case where the outside air is cooler but with a higher dew point, opening the windows would release sensible heat but introduce latent heat (heat that would have to be removed by the A/C unit when it condensates the water and lowers the humidity). In this case, you would want to make sure the enthalpy of the outside air is less than the enthalpy of the inside air. The easiest way to do this is through a psychrometric chart. Using this example, https://www.wikihow.com/images/thumb/e/ec/Read-a-Psychrometric-Chart-Step-6.jpg/aid10153214-v4-728px-Read-a-Psychrometric-Chart-Step-6.jpg (https://www.wikihow.com/images/thumb/e/ec/Read-a-Psychrometric-Chart-Step-6.jpg/aid10153214-v4-728px-Read-a-Psychrometric-Chart-Step-6.jpg), observe the diagonal lines for constant enthalpy, the horizontal lines for dew point, and the vertical lines for temperature. If the outside air has more enthalpy than the inside air for the given temperature and dew point, opening the windows would be counterproductive.
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Thank you @Boofinator for that description. That may have been the most helpful bit of information I read so far on this issue although I also am still a bit confused.
Not to over simplify, but it sounds like as long as the dew point is similar from outside to inside and condensation won't form on the windows, then I should be ok to leave them open and not worry about too much moisture coming inside the home?
Yes, you are correct: if the dew point is the same inside and out, then you need not worry at all about moisture coming in. Things get a little tricky during the summer months if the outside dew point is higher than the inside dew point. Not to get too nerdy here, but scientists and engineers separate heat into two categories: sensible and latent. Sensible heat relates to the heat required to change the temperature, and latent heat relates to heat that changes some property other than the temperature (for example, humidity). So in the case where the outside air is cooler but with a higher dew point, opening the windows would release sensible heat but introduce latent heat (heat that would have to be removed by the A/C unit when it condensates the water and lowers the humidity). In this case, you would want to make sure the enthalpy of the outside air is less than the enthalpy of the inside air. The easiest way to do this is through a psychrometric chart. Using this example, https://www.wikihow.com/images/thumb/e/ec/Read-a-Psychrometric-Chart-Step-6.jpg/aid10153214-v4-728px-Read-a-Psychrometric-Chart-Step-6.jpg (https://www.wikihow.com/images/thumb/e/ec/Read-a-Psychrometric-Chart-Step-6.jpg/aid10153214-v4-728px-Read-a-Psychrometric-Chart-Step-6.jpg), observe the diagonal lines for constant enthalpy, the horizontal lines for dew point, and the vertical lines for temperature. If the outside air has more enthalpy than the inside air for the given temperature and dew point, opening the windows would be counterproductive.
Upon further reflection, my above statement holds true given a single exchange of air between inside and outside with perfect insulation, but if you consider a thermal mass component some interesting things are going on. In this case, the air inside the house quickly reaches the outside ambient dew point (humidity), but due to thermal mass of the materials inside the house, the air will continue pulling energy from inside due to the temperature difference for many hours after the windows open. The effect of this would be two-fold (both owing to thermal mass contributions): 1) on the downside, the temperature inside will remain elevated from the outside temperature, thereby in the short-term (the dynamic phase) the room will get hotter (sensible heat decreases much slower than latent heat increases); 2) on the upside, the energy will be continually decreasing due to the thermal mass, so that at steady-state equilibrium the total enthalpy of the air inside the house with equal that of outside, but the total energy (to include that lost from the thermal mass) will be much much lower, thereby saving a lot of energy.
So in summary, if there was a situation where the enthalpy inside and outside were equal with the outside being cooled but more humid, opening the doors would save you energy while at the same time making you much hotter at the beginning due to the different time constants associated with the latent and sensible heat changes.
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We just installed Gila Brand Tint to our west-facing sliding glass door. We chose the 70% blockage tint as we would still like some light to come in during the winter. So far, so good... installation was tedious, but there's a lot of forgiveness built into the product. Love the look and it has cut down on a lot of heat entering our home.
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We do not have AC. We are FIREd so have someone at home most days - this is our strategy:
Open all windows at night as long as the temperature outside is cooler than inside.
Keep all shades pulled on the E and S sides of the house in the morning
Open windows on the N and W sides of the house.
Turn on fans (ceiling fans are worth considering if you don't have them) to circulate cooler air throughout the house as long as outside air temp is cooler than inside.
Close windows as outdoor temp crosses indoor temp.
Pull shades on W side of house.
When I lived in Michigan, our home had a fan mounted in the ceiling, that sucked air from the home and pushed it into the attic. At night we would turn that fan on and open a window in the bedroom a few inches. This created a breeze into the window and across our bed. It drew in the cool night air, it was great!
The fan was in the hallway, kind of central in the home, so it would work in any room.
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Our house has the attic stairs about 3ft from the return register for the HVAC
during the summer the attic stairs door is hot to the touch, so I made a box out of polyiso sheet and put weather stripping on the bottom and made a sealing flange on the stairs, so it fits over the stairs
now the attic stairs door is cool and I have noticed our HVAC runs a lot less during the summer
Another thing is sealing all the doors
I have been really considering having a company come and do that spray inwall foam to the sunny sides of our house
Also been thinking about adding sheets of foil faced polyiso in between the rafters to build up the R value
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Anyone else looking into solar powered AC / heat pump units? I would be happy to skip the cost and depreciation of batteries because if you need AC it’s usually because the sun is shining. More cheap panels would make up for a lack of expensive batteries. An auxiliary unit could prevent the central AC from kicking on as often and maybe save a couple hundred per summer.
The point where I lack understanding is how to wire it so that it only turns on the AC when there is sufficient wattage available.
Example:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F143349564722
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Anyone else looking into solar powered AC / heat pump units? I would be happy to skip the cost and depreciation of batteries because if you need AC it’s usually because the sun is shining. More cheap panels would make up for a lack of expensive batteries. An auxiliary unit could prevent the central AC from kicking on as often and maybe save a couple hundred per summer.
The point where I lack understanding is how to wire it so that it only turns on the AC when there is sufficient wattage available.
Example:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F143349564722
Biggest problem with this plan is that the A/C compressor needs a lot of power on startup, then moves to a lower power level while running. If you size the solar to be able to start the system up, you'll have a lot of wasted capacity (still might be cheaper than mixing in a battery though). If you did add a battery to assist with startup, a lithium chemistry is likely best - doesn't mind extended periods of low charge, can absorb/release energy quickly relative to capacity/size.
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Anyone else looking into solar powered AC / heat pump units? I would be happy to skip the cost and depreciation of batteries because if you need AC it’s usually because the sun is shining. More cheap panels would make up for a lack of expensive batteries. An auxiliary unit could prevent the central AC from kicking on as often and maybe save a couple hundred per summer.
The point where I lack understanding is how to wire it so that it only turns on the AC when there is sufficient wattage available.
Example:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F143349564722
Biggest problem with this plan is that the A/C compressor needs a lot of power on startup, then moves to a lower power level while running. If you size the solar to be able to start the system up, you'll have a lot of wasted capacity (still might be cheaper than mixing in a battery though). If you did add a battery to assist with startup, a lithium chemistry is likely best - doesn't mind extended periods of low charge, can absorb/release energy quickly relative to capacity/size.
I’ve thought about this too. The price of panels is falling faster than the price of batteries, so having more panel capacity than needed is at some point more economical than having a steadily-deteriorating battery.
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Anyone else looking into solar powered AC / heat pump units? I would be happy to skip the cost and depreciation of batteries because if you need AC it’s usually because the sun is shining. More cheap panels would make up for a lack of expensive batteries. An auxiliary unit could prevent the central AC from kicking on as often and maybe save a couple hundred per summer.
The point where I lack understanding is how to wire it so that it only turns on the AC when there is sufficient wattage available.
Example:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F143349564722
Biggest problem with this plan is that the A/C compressor needs a lot of power on startup, then moves to a lower power level while running. If you size the solar to be able to start the system up, you'll have a lot of wasted capacity (still might be cheaper than mixing in a battery though). If you did add a battery to assist with startup, a lithium chemistry is likely best - doesn't mind extended periods of low charge, can absorb/release energy quickly relative to capacity/size.
I’ve thought about this too. The price of panels is falling faster than the price of batteries, so having more panel capacity than needed is at some point more economical than having a steadily-deteriorating battery.
There are other solutions to this using capacitors. It was all the rage to build your own "mini-maximiser" in renewable energy / small hold farming circles a while ago. I'll see if I can find any links.
Here is one that may give you an idea of what is possible:
http://www.voltscommissar.net/minimax/minimax.htm
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Yay! We appear to have reached the glorious time of year where it cools off and humidity isn't too high at night so we can leave the windows open.
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Anyone else looking into solar powered AC / heat pump units? I would be happy to skip the cost and depreciation of batteries because if you need AC it’s usually because the sun is shining. More cheap panels would make up for a lack of expensive batteries. An auxiliary unit could prevent the central AC from kicking on as often and maybe save a couple hundred per summer.
The point where I lack understanding is how to wire it so that it only turns on the AC when there is sufficient wattage available.
Example:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F143349564722
Biggest problem with this plan is that the A/C compressor needs a lot of power on startup, then moves to a lower power level while running. If you size the solar to be able to start the system up, you'll have a lot of wasted capacity (still might be cheaper than mixing in a battery though). If you did add a battery to assist with startup, a lithium chemistry is likely best - doesn't mind extended periods of low charge, can absorb/release energy quickly relative to capacity/size.
I’ve thought about this too. The price of panels is falling faster than the price of batteries, so having more panel capacity than needed is at some point more economical than having a steadily-deteriorating battery.
There are other solutions to this using capacitors. It was all the rage to build your own "mini-maximiser" in renewable energy / small hold farming circles a while ago. I'll see if I can find any links.
Here is one that may give you an idea of what is possible:
http://www.voltscommissar.net/minimax/minimax.htm
Great link. Probably best for me to start by buying an old electrical engineering 101 textbook off eBay! This is a lot more complicated than house wiring.
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The last couple days have been amazing outside, so I have had the AC off and the windows open. It's glorious. I also discovered that Carrier finally updated their smartphone app so now at last I can remotely control my HVAC as they had promised when I bought the system. Hooray!
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An amusing, tangentially-related observation: Somehow I got on this "Nextdoor" group, where people gripe and moan about all sorts of shit. The latest was a conspiracy by the energy company to overcharge customers. Dozens must have chimed in agreement, because they couldn't ever remember having $400 or $500 energy bills before. I resisted posting that my bill was about 10% of theirs, for fear I'd have an angry mob with torches and pitchforks at my door later that night.
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things to help keep the house cool:
1. Keep the blinds finished to keep off direct daylight.
2. Mop the floors with virus water.
3. Put a major can of ice before a fan and let the air blow over it.
4. can also use any dehumidifier which is best suited some are there https://www.amardeepchair.com/
4. During the evening, open a window toward one side of the house, and another where you need to be coolest. Put a fan in the far window so it hauls the warm let some circulation into. In the first part of the day, or when it begins getting warm, close the windows to keep the sight-seeing out.
That was helpful, thanks a lot.
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We use remarkably little energy to cool the house at this time of year.
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I didn't read through this whole thread now, but I think the correct strategy for "keeping your house cool" depends a lot on what kind of climate you live in. A strategy that's effective in Tucson is probably not going to work as well in Hawaii, and vice versa.
Here in Hawaii, I think there are two magic ingredients to keeping your house cool: Lots of airflow, and attic insulation. If your house is exposed to the trade winds and you are able to open up windows so you get cross flow through the house, you're going to be set. Insulating the attic (or adding PV!) to prevent the roof from radiating heat into the living space is the only other thing that you might need. Sun shining in through the windows, or even heating the sides of the house, is basically not an issue because the Sun is always very high in the sky and all houses here have 3,4, or even 5' eaves because of all the rain.
Now, if your house is sheltered from the trades, it will likely get miserably hot. The other viable strategy then is to seal yourself in and use AC, but that will be very expensive given power is $0.35/kWh.
This strategy works because while the Sun is strong here, the winds are always a pleasant temperature since they are regulated by all the water around. It's not going to work in an inland situation where the surrounding land heats up during the day.