Author Topic: High Humidity: How do you keep it out of your home??  (Read 3467 times)

aes421

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High Humidity: How do you keep it out of your home??
« on: May 21, 2019, 11:19:59 AM »
Hello all,

DH and I bought out first home last month, and managed to keep the electric bill to $30 (2000 sq ft) by not running the AC.  Temps were great due to cooler temperatures.

Now the temperatures are still not terrible (85 at peak), but outdoor humidity is getting up to 90%.  Heat doesn't bother me too much, but the house is getting into upper 60% and even over 70% occasionally and I've heard that can cause mold growth/bugs/other damage to the home.

We've already switched to taking 4 cool showers a week (2 each), cooking outside to avoid boiling water, and bought a few plants that are supposed to absorb humidity.


I've resorted to running the AC to keep the humidity inside at bay. What do you other mustachians do to solve humidity problems in your home?

dougules

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Re: High Humidity: How do you keep it out of your home??
« Reply #1 on: May 21, 2019, 11:35:26 AM »
I think old houses in the south were built to get some airflow going through, although I'm not exactly sure.  Find somebody in their 80s and ask how things worked when they were younger.  AC would have been new for them. 

One thing I do know is that all old southern houses have porches.  I think people spent a lot of time on the porch during the dead of summer. 

rothwem

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Re: High Humidity: How do you keep it out of your home??
« Reply #2 on: May 21, 2019, 12:31:20 PM »
Maybe this sounds dumb, but have you considered a dehumidifier? I’m not sure about the energy costs of that versus the A/C, but such a device does exist. You can even buy models that hook up to your ducting to lower the humidity in your whole house.

TVRodriguez

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Re: High Humidity: How do you keep it out of your home??
« Reply #3 on: May 21, 2019, 12:46:18 PM »
Growing up, my mom always ran a dehumidifier in our basement in the summers.  We had no air conditioning other than two window units (one in parents' bedroom on second floor and one in the dining room on first floor).  I can't speak to the numbers b/c I was a child, but it seemed to help keep humidity down afaik.

Sibley

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Re: High Humidity: How do you keep it out of your home??
« Reply #4 on: May 21, 2019, 12:54:21 PM »
Air flow. 50%+ humidity you're going to end up with mold issues.

bacchi

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Re: High Humidity: How do you keep it out of your home??
« Reply #5 on: May 21, 2019, 12:58:13 PM »
1) Find any holes and close them up. External outlets and light cans in the attic are big leakers.
2) Get a whole house dehumidifier. Some are thin enough to span wall studs. They're not cheap to run but it beats having moldy books.

GuitarStv

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Re: High Humidity: How do you keep it out of your home??
« Reply #6 on: May 21, 2019, 01:08:33 PM »
Humidity is a tough one.  Very high humidity is just miserable to live with.  I use air conditioning in the summer when humidity gets unbearable (up above 80+ percent humidity with temperatures above thirty five celcius (95 F).  AC knocks a lot of the humidity out of your home.

Dehumidifiers work by heating your home.  They're kinda miserable to use in the summer . . . and I've only ever seen them used in basements to keep moisture problems at bay.

You can use less A/C if your home is well insulated, if you've got good airflow through the home (no airflow means that humidity becomes a bigger problem and mold is more likely to form), and if you cover any bright windows during the day.

Home Stretch

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Re: High Humidity: How do you keep it out of your home??
« Reply #7 on: May 21, 2019, 01:37:46 PM »
I've played the game of trying to cut down on summer A/C costs here in the super-humid southeast US. For us it boiled down to a simple pro/con list.

Cons:
  • super sticky and uncomfortable in the house
  • not sleeping as well at night due to humidity
  • whole house smelled musty and all smells are amplified
  • had to spend more precious time cleaning every surface to keep smells at bay
  • dog was visibly uncomfortable
  • coming in from sweaty activity outside provided limited relief/kept sweating for a while
  • risk of mold/mildew greatly increased
  • no friends want to visit

Pros:
  • Save $50/mo

Needless to say we made it about two weeks before we agreed that this was more than we were willing to put up with. If you want to live without A/C, you really do need to live somewhere with low humidity, like CO, which is why MMM's advice on this topic gets a bit of a facepunch from me, because he's obviously never lived through a summer down here.

dougules

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Re: High Humidity: How do you keep it out of your home??
« Reply #8 on: May 21, 2019, 02:20:16 PM »
Maybe this sounds dumb, but have you considered a dehumidifier? I’m not sure about the energy costs of that versus the A/C, but such a device does exist. You can even buy models that hook up to your ducting to lower the humidity in your whole house.

Dehumidifiers put out a lot of heat.  There is a whole lot of energy that's released when water changes state.  We use a dehumidifier to dry clothes in the laundry room sometimes, but the laundry room always feels like Arizona when we do. 

rothwem

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Re: High Humidity: How do you keep it out of your home??
« Reply #9 on: May 21, 2019, 02:23:48 PM »
Maybe this sounds dumb, but have you considered a dehumidifier? I’m not sure about the energy costs of that versus the A/C, but such a device does exist. You can even buy models that hook up to your ducting to lower the humidity in your whole house.

Dehumidifiers put out a lot of heat.  There is a whole lot of energy that's released when water changes state.  We use a dehumidifier to dry clothes in the laundry room sometimes, but the laundry room always feels like Arizona when we do.

Gotcha, yeah I just did some reading there. 

An interesting option looks like a "heat pipe" HVAC system.  Basically dries out the air more thoroughly than a regular air conditioner.  I'm not sure if that's something used in home HVAC systems though, or if its more for industrial setups. 

dougules

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Re: High Humidity: How do you keep it out of your home??
« Reply #10 on: May 21, 2019, 02:28:50 PM »
I've played the game of trying to cut down on summer A/C costs here in the super-humid southeast US. For us it boiled down to a simple pro/con list.

Cons:
  • super sticky and uncomfortable in the house
  • not sleeping as well at night due to humidity
  • whole house smelled musty and all smells are amplified
  • had to spend more precious time cleaning every surface to keep smells at bay
  • dog was visibly uncomfortable
  • coming in from sweaty activity outside provided limited relief/kept sweating for a while
  • risk of mold/mildew greatly increased
  • no friends want to visit

Pros:
  • Save $50/mo

Needless to say we made it about two weeks before we agreed that this was more than we were willing to put up with. If you want to live without A/C, you really do need to live somewhere with low humidity, like CO, which is why MMM's advice on this topic gets a bit of a facepunch from me, because he's obviously never lived through a summer down here.

This makes me feel like going into old southern man story time mode.

One time I was over at my grandmother's house with a bunch of other family, and it was the middle of the summer.  We had a storm come through, and it knocked out the power.  Then the sun came back out, and things started to get steamy.  As it started to get a little harder to breathe my aunt and I started discussing what they did back in the day.  She made the comment "well I guess you just got used to it", and without skipping a beat at all my usually quiet great grandmother pipes up out of the corner of the room "NO YOU DIDN'T".

Rosy

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Re: High Humidity: How do you keep it out of your home??
« Reply #11 on: May 21, 2019, 02:38:54 PM »
Your choice is using AC and paying an extra $50 a month - or - risk damaging your home through mold which can be a rather expensive fix (more expensive than AC) and once you've had mold it tends to return.
Your books and papers and photographs will be destroyed by the humidity. I found that out quickly. It is the reason why I had AC extended to our utility room - I couldn't store anything without running into problems.

Personally, I can't sleep in high humidity, it's miserable. Worse, just opening the door in the morning to the steamy sauna outside leaches all the energy from my body. I hate summers in Florida.
... and you're right, if you store groceries the cut off temperature is 76 degrees, otherwise, you'll end up with bugs in your flour and other issues.

Personal comfort and protection of my home and belongings are where I draw the line. I don't see anything mustachian about exposing my home to mold.

LifeHappens

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Re: High Humidity: How do you keep it out of your home??
« Reply #12 on: May 21, 2019, 02:41:23 PM »
You can get a whole house dehumidifier. They live outside, next to your AC unit. We have not gone that route so I can't tell you if they work well enough to forgo AC entirely. They are meant to supplement the work your AC is doing.

As others have said, there isn't a great way to opt out of AC entirely for the whole of a SE US summer. The humidity just destroys buildings. Yes, people used to live without it, but their houses were in a constant state of decay. Read some Southern Gothic literature and notice all the references to mold, mildew and rot. The struggle is real.

bacchi

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Re: High Humidity: How do you keep it out of your home??
« Reply #13 on: May 21, 2019, 03:02:29 PM »
You can get a whole house dehumidifier. They live outside, next to your AC unit. We have not gone that route so I can't tell you if they work well enough to forgo AC entirely. They are meant to supplement the work your AC is doing.

Right. A whole house humidifier vents the heat outside, where it belongs. If you have a 2x6 exterior wall, Ultra-Aire sells one that fits inside the studs.

https://www.ultra-aire.com/dehumidifiers/md33/

You can also turn down the inside blower on your AC. The coils stay cold longer, which means more dehumidifying, but it comes with lowered efficiency (and it takes longer to cool down).

Some mini-splits have a "dry" mode. Mine drops the fan speed and cools the room to lower than the set point; if humidity is still a problem, it then uses the heater to bring the temperature up and starts over in cooling mode. Again, not the most efficient.


FIREstache

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Re: High Humidity: How do you keep it out of your home??
« Reply #14 on: May 21, 2019, 04:45:11 PM »

I used to run the AC minimally, usually tried to avoid it until it got into the upper 80's in the house.  In the evenings, I would put a fan in the window to bring in cooler air so that I could sleep.  I didn't have a problem for years, but eventually had some mold on some leather and on some particle board in my basement.  So, I immediately started running the AC trying to keep it 78 to 82 degrees, and even in the evenings, I don't blow in air from outside if the humidity is high.  I haven't seen mold on anything in the years since I started using the AC more.

dougules

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Re: High Humidity: How do you keep it out of your home??
« Reply #15 on: May 22, 2019, 10:39:14 AM »
Maybe you could look into solar panels to offset your power consumption on AC.  The good thing is that your peak demand for power for cooling will also be during the peak for the solar panels. 

aes421

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Re: High Humidity: How do you keep it out of your home??
« Reply #16 on: May 23, 2019, 08:14:31 AM »
Thanks for the tips all!

I've started realizing my downstairs AC may not be working.  I measured humidity on the upstairs unit and its able to main 55% humidity all the way up to 82 degrees, while my downstairs unit needs to be set to about 70 degrees and ran nearly 24/7 just to try to keep humidity below 60%.  Something definitely must be wrong.

I'm going to start learning about HVAC's and see if there's anything I can do to fix this, and in the mean time I'll buy a dehumidifier from craigslist to help.

If you've got any tips on how to fix the AC, please post them.  Going to start by inspecting and cleaning the evaporator coil.

Rosy

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Re: High Humidity: How do you keep it out of your home??
« Reply #17 on: May 23, 2019, 08:33:45 AM »
Just wanted to add - The one thing that helps the most with the merciless summer heat and the cost of your AC is the architecture of your home.

We have an old block home with an overhang of about five feet all around the house, even the carport.
That overhang is worth its weight in gold - it does its job well.

That is also the reason they used to have wrap around porches. The placement of your windows - to allow for cross ventilation.

Boofinator

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Re: High Humidity: How do you keep it out of your home??
« Reply #18 on: May 23, 2019, 08:39:05 AM »
I've started realizing my downstairs AC may not be working.  I measured humidity on the upstairs unit and its able to main 55% humidity all the way up to 82 degrees, while my downstairs unit needs to be set to about 70 degrees and ran nearly 24/7 just to try to keep humidity below 60%.  Something definitely must be wrong.

I'm going to start learning about HVAC's and see if there's anything I can do to fix this, and in the mean time I'll buy a dehumidifier from craigslist to help.

If you've got any tips on how to fix the AC, please post them.  Going to start by inspecting and cleaning the evaporator coil.

A couple things to keep in mind:

Your downstairs unit has removed much more water from the air than your upstairs unit, because colder air can hold less water. A psychrometric chart might help you visualize what's going on (https://upload.wikimedia.org/wikipedia/commons/9/9d/PsychrometricChart.SeaLevel.SI.svg). This chart has temperature on the x-axis and amount of water in the air on the y-axis, with the relative humidity being the red curves. Note what happens to the humidity as the temperature decreases without a decrease in water vapor.

Another thing to keep in mind is that the water is pulled out from the air during the coldest part of the refrigeration cycle, right after the expansion valve. If the air is slightly warmer at this stage for the downstairs AC relative to the upstairs AC, it simply cannot remove as much water. So there's a possibility the downstairs AC is running less efficiently; cleaning the evaporator coils is a good start, but you might need a tune-up if you have a very slow refrigerant leak.

Home Stretch

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Re: High Humidity: How do you keep it out of your home??
« Reply #19 on: May 23, 2019, 09:19:02 AM »
@aes421 - are you uncomfortable at 60% humidity? My thermostat displays humidity levels and I find it feels quite "dry" to me as long as the humidity is below 70%.

If the indoor temperature is never reaching where you set it, even after more than an hour, then it definitely points to a problem with the A/C unit. If it's older than 5-10 years, it's not uncommon to have a coolant leak from the evaporator coil due to corrosion or rust. Not something you can fix yourself, since it can involve environmentally harmful refrigerants. I'd recommend getting an HVAC tech out as soon as you can (actually something I'd recommend to anyone moving into a new house just to get an inspection/tune-up as a baseline).

ChpBstrd

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Re: High Humidity: How do you keep it out of your home??
« Reply #20 on: May 23, 2019, 09:29:26 PM »
We started to find mold growing on wood furniture and hardwood floors when we tried setting the AC to 75 F.

So keep the AC at 72 at most and DO NOT TAKE LONG STEAMY SHOWERS IN THE SUMMER. The lack of 50 gallons of steaming hot water sprayed twice a day, plus a lack of dishwashers and interior washing machines / dryers is why houses built before AC did not molder away. If you want to live like people did in the pre-AC era, it's the whole package or nothing.

chemistk

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Re: High Humidity: How do you keep it out of your home??
« Reply #21 on: May 24, 2019, 06:08:36 AM »

This makes me feel like going into old southern man story time mode.

One time I was over at my grandmother's house with a bunch of other family, and it was the middle of the summer.  We had a storm come through, and it knocked out the power.  Then the sun came back out, and things started to get steamy.  As it started to get a little harder to breathe my aunt and I started discussing what they did back in the day. She made the comment "well I guess you just got used to it", and without skipping a beat at all my usually quiet great grandmother pipes up out of the corner of the room "NO YOU DIDN'T".

This made me chuckle, thanks for the story!

To the OP - Mold/Mildew start to grow at roughly 50% RH. With good airflow, you can get away with a little bit of a higher number but ultimately you'll definitely want to be doing whatever you need to keep the humidity levels below that threshold. Especially if you have anyone in your family with breathing problems.

dougules

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Re: High Humidity: How do you keep it out of your home??
« Reply #22 on: May 28, 2019, 10:02:36 AM »
@aes421 - are you uncomfortable at 60% humidity? My thermostat displays humidity levels and I find it feels quite "dry" to me as long as the humidity is below 70%.

When it gets hot the relative humidity isn't as relevant to how it feels as the amount of moisture total in the air.  Since the amount of moisture the air can hold goes up exponentially with temperature, a low relative humidity may still be really humid when it's good and hot.  35% humidity at 100F will feel more humid than 70% humidity at 75F. 

You should watch the dew point since it doesn't vary with the temperature.  60F is where you just start to notice the humidity.  Anything over 70F is nasty, even if the temperature is relatively low. 

willjj90

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Re: High Humidity: How do you keep it out of your home??
« Reply #23 on: May 30, 2019, 02:39:50 PM »
Firstly... and the obvious.. I would get a professional in your area to assess the situation. There might be something causing excessive moisture that you're unaware of that may be able to be fixed.

But you could always have water working its way into your foundation and creating moisture as well. I personally would check to make sure the ground outside is properly graded to keep as much run off away from the house as possible.

I would also run a dehumidifier if need be as well as A/C (A/C removes moisture from the air as well)

But I'm no pro, that's just what I would do.

AlotToLearn

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Re: High Humidity: How do you keep it out of your home??
« Reply #24 on: May 30, 2019, 05:52:01 PM »
Does anyone here own a whole house dehumidifier?

GuitarStv

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Re: High Humidity: How do you keep it out of your home??
« Reply #25 on: May 30, 2019, 06:42:56 PM »
Does anyone here own a whole house dehumidifier?

Yes.

But we usually call it an air conditioning unit.

SwordGuy

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Re: High Humidity: How do you keep it out of your home??
« Reply #26 on: May 30, 2019, 10:09:36 PM »
We put a an inexpensive dehumidifier in our two basements.   We already had drains in each basement so we could just run a hose from the units and not have to remember to empty their trays.     It was a few years ago but I think they were maybe $200 each.  Worked like a charm.   Have to remember to turn them off in the winter or my skin dries out.

 

Wow, a phone plan for fifteen bucks!