Author Topic: Humidity issues  (Read 5867 times)

Leftside

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Humidity issues
« on: December 04, 2015, 02:31:28 PM »
I need some serious help here.  The house that I purchased just over a year ago has humidity issues in the winter.  I have a few humidity monitors in the house, upstairs it shows its usually around 66%.

This is obviously far too high, and it causes too much condensation on the windows to the point where it can pool on the sill below;  It's not even that cold yet (Minnesota).  Now the temperature in the second story is slightly lower because of the design of the house (2 story, furnace in basement), but still hovers around 65 degrees.

I have 5 people living in the house, and I know that adds a fair amount.  I don't think it's cooking that is causing the issue, as we can notice the condensation increases when we do a fair amount of cooking, but doesn't go down at all when we don't.  Everyone is using the bathroom fan while showering.

I need ideas.  I am thinking it's the furnace, but I don't know what to look for.

Help.

justajane

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Re: Humidity issues
« Reply #1 on: December 04, 2015, 03:32:47 PM »
It seems to me that, as it gets colder, the situation should resolve itself, since the increased use of heat will dry out the internal air.

I noticed condensation on the inside of my basement window last week. Running a dehumidifier for just a few hours solved the issue.

What do you think it would be on the furnace that would be causing this? Does the furnace have a whole house humidifier on it? If so, I would turn it off for the time being.

One of the benefits of using of dehumidifier in the winter is that that also produces heat. It's like a space heater. I would start with one in your basement and see if it solves the problem on the second floor. If it doesn't, then move it upstairs and see if that does the trick. The risk there is that it is collecting water and, if it leaks or spills, could be bad for your flooring. But you don't have to run it all the time, especially since they use a shit-ton of electricity.
« Last Edit: December 04, 2015, 03:34:32 PM by justajane »

justajane

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Re: Humidity issues
« Reply #2 on: December 04, 2015, 03:36:48 PM »
If the temperature on your second story is lower than the first floor, you likely need to blow some insulation in that attic. We did that in our first year of homeownership, and it raised the temperature upstairs by 4 degrees or more.

Sadly, it's now cold up there, since we have solar panels and are losing any thermal gain from the roof.

TrMama

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Re: Humidity issues
« Reply #3 on: December 04, 2015, 04:07:22 PM »
This is a really common problem in cold areas. The problem gets worse as the outside temp drops, since it makes the interior face of the windows colder, thereby increasing the condensation.

The only real fix (besides opening up all the windows to let the humid air out) is to install an air exchanger. They aren't cheap, but they work great.

In the meantime, much of the humidity is coming from your warm showers. Replace any standard shower head with a low flow model and keep showers short. You can also run a dehumidifier (preferably near a bathroom) for a few hours/day to lower the humidity. I also recommend wiping down any really wet windows, so you don't get mold and/or damaged sills.

Obviously, do not dry laundry indoors.

lakemom

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Re: Humidity issues
« Reply #4 on: December 04, 2015, 06:52:30 PM »
It may not be the humidity so much as it is the windows themselves.  Older or poorly installed windows will be colder (the temp of the glass rather than feel of the room) than newer/properly installed windows.  You could try either storm windows installed on the outside of the window or plastic window film on the insides of the window.  It may help contain the issue by adding an extra layer of air between the moisture and the window.

Greg

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Re: Humidity issues
« Reply #5 on: December 04, 2015, 09:13:17 PM »
Check around the windows for air leaks, caulk and seal cracks if needed.  What kind of windows?  Single or double pane?  Vinyl, aluminum, or wood frames?  Makes a difference. 

See if you can install a bigger bath fan.  I specify 80CFM fans as a minimum in my area, code might say 50CFM is all that is needed.  Make sure the fan outlet is not blocked.

If the fan is in good working order, consider a timer switch or a humidistat switch.  Ceiling fans help because they stir the air and help keep moist air moving around.

justajane

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Re: Humidity issues
« Reply #6 on: December 05, 2015, 06:15:14 AM »
It may not be the humidity so much as it is the windows themselves. 

This is a good point. We have a few crappy single pane windows left in our house, and they often get condensation in the winter, even when it is colder and the heat is running all the time. If you feel comfortable and mold isn't growing, it may not be as big of a deal as you think.

BudgetSlasher

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Re: Humidity issues
« Reply #7 on: December 05, 2015, 09:01:14 PM »
My first thought when reading your complaint that you have too much humidity in your house at this time of year was "I wish I had that problem." I recently installed a bypass humidifier to bump up our humidity during the winter.

Our low humidity is a by product of air infiltration . . . and probably too much house for the number of people living in it.

Humidity comes from people in the forms of breathing, sweating, and the like; there is nothing you can do about this source of humidity . . . at least short of shipping a kid off the college or off to work. It also comes form day to day activity, such as showering; if you do not already running the bathroom exhaust fan during a shower (this is a source of conflict in our house) and for a time after the shower may help. If you range hood exhaust outside, be more dutiful about running it when cooking, especial if you cook with gas/propane. If it does not vent outside, you may want to consider changing from a recirculating exhaust hood to venting outside.

If you cannot address the source of humidity, a heat recovery ventilation (HRV) system is what you should look into. Even though our house is not tight enough to need one (since certain steps in the blueprints were skipped) we have one tied into our bathroom exhaust fans. It is not necessary to be tied into the bathroom exhausts; in its simplest form a HRV takes humid air from inside the house and vents it outside while bringing dry air from outside into the house. To conserve energy the outgoing air and incoming air are run across a heat exchanger to recapture some amount of heat.

lthenderson

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Re: Humidity issues
« Reply #8 on: December 06, 2015, 01:48:02 PM »
Do you have a whole house humidifier installed and just don't know it? I have never had a house that I considered too humid in the winter time and always install whole house humidifiers to add more humidity. In early or late winter when the heater isn't running as often, I turn it on high to pump as much moisture as possible into the house during the short and infrequent heat cycles. In the depths of winter, I have to dial it back or I will start to get condensation on the windows and such.  Mine looks similar to the one in the link below and is attached to a duct above the heating unit.

http://www.amazon.com/Aprilaire-Whole-house-Bypass-Humidifier-Control/dp/B005DS4EC4/ref=sr_1_11?s=home-garden&ie=UTF8&qid=1449434801&sr=1-11&keywords=whole+house+humidifier

BudgetSlasher

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Re: Humidity issues
« Reply #9 on: December 06, 2015, 05:08:56 PM »
Perhaps I am missing something and if so I would love to learn something today.

I have read multiple posts calling attention to the type and condition of the windows, along with the condition of the weather stripping. I understand that these are items that can influence condensation and even if they are not the cause of the condensation correcting issues can save on heating costs.

However, since the original poster indicated that he has been taking readings which show that the relative humidity upstairs is routinely 66 percent (and most recommended indoor humidity levels seem to max out in the 50-55 range), will any adjustments to the windows short of replacing them with ultra-high efficiency (and ultra high cost) windows really address the condensation issue?

Back to the original post, do you have a damp or humid cellar/basement/crawl space below the house, especially one that does not have an effective air barrier between it and the living space? In this area of the country it is not uncommon for people to run dehumidifiers in their basement to control humidity (and mold). I have a poured concrete basement which stays dry, but I have a dehumidifier set to 50% which ends up running only during the summer, without it things get a little "musty".
« Last Edit: December 06, 2015, 05:13:45 PM by BudgetSlasher »

patrat

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Re: Humidity issues
« Reply #10 on: December 07, 2015, 06:59:20 AM »
Humidity is really only a big problem when it condenses somewhere you don't want it.

Your windows sweating are actually functioning as dehumidifiers. If you regularly wipe them, you have a poor man's dehumidifier. If you were to say, install better insulated windows your humidity level indoors would be higher, until it found the next thing to condense on. In the place I rent, the old single pane windows were replaced with decent double panes before I moved in. Those old windows pulled out the humidity by sweating. The new ones barely sweat. The unintended consequence, is that now the humidity condenses in the air conditioning ducts that run in the attic, and rain down through the ceiling vents on cold days. When I am cranking out the humidity with a lot of showering or cooking I will actually open the insulated doors, leaving the single pane glass storm doors to sweat, pulling out humidity.

I have to completely block of the  ceiling vents in winter (heat is from radiators).

The humidity comes from cooking, dishwasher (especially drying cycle), showering, breathing, and any clothes drying that does not effectively exhaust to the outdoors. Any combustion that does not exhaust to the outside, such as gas stove, gas oven, or ventless gas heaters add humidity. Candles add humidity. Have your chimney/ heater flu checked, for both the furnace and the hot water heater, to insure they are working properly. Air drying clothes indoors adds humidity (rarely a problem for MMM, in dry Longmont)

Check your dryer vent and bathroom vent, make sure both are working well, clean the ducts. Always use the vent hood on your stove, lacking a vent open two windows on either side of the kitchen, and maybe have a fan in one pulling are out. Outside air is not a problem source of humidity when it is colder outside than inside, that outside air is almost always drier.

former player

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Re: Humidity issues
« Reply #11 on: December 07, 2015, 09:32:18 AM »
Provided you have no structural issues with damp in the house, then the simple answer is that you need more ventilation. 

If the problem is with your second storey, I am guessing those are bedrooms.  The easy answer is that you need to air out every bedroom every day, by opening a small window for up to half an hour.  Yes, you lose heat, but it should solve the condensation problem and is an immediate and relatively cheap solution (you won't need the bedrooms warm again until evening, by which time heat will have risen through the house anyway).

The more complicated solutions are humidifiers, air exchangers and the like.  If you've been prioritising "a few humidity monitors" over simply airing out the bedrooms as your grandmother used to do, you may prefer them.

TrMama

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Re: Humidity issues
« Reply #12 on: December 07, 2015, 04:00:39 PM »
Perhaps I am missing something and if so I would love to learn something today.

I have read multiple posts calling attention to the type and condition of the windows, along with the condition of the weather stripping. I understand that these are items that can influence condensation and even if they are not the cause of the condensation correcting issues can save on heating costs.

However, since the original poster indicated that he has been taking readings which show that the relative humidity upstairs is routinely 66 percent (and most recommended indoor humidity levels seem to max out in the 50-55 range), will any adjustments to the windows short of replacing them with ultra-high efficiency (and ultra high cost) windows really address the condensation issue?

Since the OP lives in Minnesota, we can assume a couple things:

1. It's much colder outside than it is inside.
2. The house is well insulated and has decent windows that have been installed/maintained to prevent drafts. AKA the house is "tight".
3. It's so cold outside that the OP doesn't want to open the doors/windows to ventilate the house because this would be uncomfortable and increase is heating bill.

Given the above, even if he replaced the windows with the best possible version, they will still always be colder than the other exterior walls and will thus collect condensation. This is just the nature of windows.

Interior humidity comes from breathing, showering/bathing and cooking. I did not suggest the OP stop his family from breathing, since that's impractical. They also presumably don't want to stop cooking or washing. However, even if they did stop washing and only ate dry food, they'd still get window condensation just from breathing. Ever slept in a cold camper with all the windows closed? By morning it "rains" inside.

Therefore, the only other way to address the problem is to remove the humidity from the air. An air exchanger (aka an HRV) is the silver bullet solution. They are connected to a humidistat and run according to need. Many, many homes in cold climates have these. We had one when we lived in Quebec and it worked nicely.  It also cost $2500.

A dehumidifier works less well, but is much cheaper.

Wiping the windows is the least desirable option because it doesn't actually remove the water from the house. Now you just have a wet towel laying in the hamper.

worms

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Re: Humidity issues
« Reply #13 on: December 15, 2015, 07:03:27 AM »

Wiping the windows is the least desirable option because it doesn't actually remove the water from the house. Now you just have a wet towel laying in the hamper.

Unless you use one of these: https://www.kaercher.com/uk/home-garden/window-vac/wv2-16333020.html