So I woke up today and found condensation on my windows. On a simple check it seems that the issue is too much humidity in the house. I bought a cheap hygrometer and checked it against my nest thermo and it checks out at 35 percent. However in the winter it plummets to about 10 to 15 percent. I was going to install a house humidifier but am leary due to window condensation. Also I checked the furnace and noticed the combustion air comes from inside the house. I guess I'm just confused because it seems like the house is too moist but my bleeding nose and constant static shock says otherwise. Help.
Humidity question
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Go ahead and install a humidifier but don't set it much above 30%.
Dryness can be caused by too much infiltration.
Dryness can be caused by too much infiltration.
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If the furnace is high efficiency with a combustion air intake connection, you should get a second pipe in there.
That should help a little with the humidity.
Other tips:
1. Open wood burning fireplaces leak a lot even with the damper close. If you have one, don't use it unless you must and seal the damper.
2. Natural draft furnaces and water heaters vent a lot of air up the chimney constantly. If you have an old standing pilot furnace with a draft hood, it should be changed out, money permitting. Would save a lot of gas. Natural draft water heaters can be replaced with sealed combustion, direct vent. (not power vent)
The draft hood draws a lot of air, at least as much as what's used for combustion.
3. Minimize use of exhaust fans
4. Do everything you can to reduce air leakage. Common areas: basement sill plates, attic hatch, access permitting.
5. Don't open doors or windows to get some fresh air. house is likely already getting too much.
A evaporative furnace mount humidifier isn't going to be able to bring it from 10 to 30%; you have to get the leakage under control. 10% is very, very low.
That should help a little with the humidity.
Other tips:
1. Open wood burning fireplaces leak a lot even with the damper close. If you have one, don't use it unless you must and seal the damper.
2. Natural draft furnaces and water heaters vent a lot of air up the chimney constantly. If you have an old standing pilot furnace with a draft hood, it should be changed out, money permitting. Would save a lot of gas. Natural draft water heaters can be replaced with sealed combustion, direct vent. (not power vent)
The draft hood draws a lot of air, at least as much as what's used for combustion.
3. Minimize use of exhaust fans
4. Do everything you can to reduce air leakage. Common areas: basement sill plates, attic hatch, access permitting.
5. Don't open doors or windows to get some fresh air. house is likely already getting too much.
A evaporative furnace mount humidifier isn't going to be able to bring it from 10 to 30%; you have to get the leakage under control. 10% is very, very low.
This surprises me as this is a newer house and isn't drafty. Is there someone I can have do an air audit? Is this worth it?
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Need more info.
No one knows where your location.
100 year old house with single pane windows?
Aluminum or steel framed windows?
Mobil home?
Bathroom, kitchen, dryer vents ran all the way to the roof or outside walls?
Running an unvented gas heater?
No one knows where your location.
100 year old house with single pane windows?
Aluminum or steel framed windows?
Mobil home?
Bathroom, kitchen, dryer vents ran all the way to the roof or outside walls?
Running an unvented gas heater?
It's worth mentioning I do not have a wood burning stove, not sure about draft from furnace, it's a high efficiency unit, only use exhaust fans in bathroom during shower and, you know, as needed. I am on phone but will attempt to post pic of furnace unit set up. Also, I'm in Pennsylvania so it's a moderate climate but we've had s few cold winters recently.
PA
2001 stick built single family with double pane
Viynl windows
Not mobile
Vents could go to roof not sure. I just installed one and did a direct vent out the side of the house with a back flow damper but it's a pos.
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14,538 Posts
You will have a problem (automatically) controlling humidity with nest.
On colder days you have to drop your humidity level in the house otherwise you get condensation on the windows. Some thermostats can automatically set back the humidity according to the outdoor temp and I don't believe nest has that ability... at least not the generation 2 version. I'm pretty sure the version 3 doesn't have it either but you will have to confirm that.
At any rate if you want this option (I have it on my thermostat and it's worth it) you would be better off buying a higher quality humidifier with a humidity controller that comes with this option.
Currently don't have a humidifier of a dehumidifier. Nest just tells me what % is at
Condensation on the windows is because the glass and inside of the house is at the Dew Point, that causes it. If you are closing drapes for the Windows, then no air is going to get to them to keep them from showing slight condensation.
It is going to be more common at night, if you have your furnace set to lower the temperature, while you are in bed. We have our thermostat set at 68 during the day, 66 at night. Our Relative Humidity always stays around 53%, just because of how our house is, which actually makes it not too dry that your nose is bothering you, along with always getting shocked.
It is going to be more common at night, if you have your furnace set to lower the temperature, while you are in bed. We have our thermostat set at 68 during the day, 66 at night. Our Relative Humidity always stays around 53%, just because of how our house is, which actually makes it not too dry that your nose is bothering you, along with always getting shocked.
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Is the house large with few people? not much activity going on like cooking, mopping floors, etc.
Some houses need humidifiers, others don't; it's a function of air leakage, climate, and the amount of moisture being produced.
A newer house can be leaky, especially if you have air ducts in a crawl space or attic. If the construction quality isn't the greatest the vapour barrier may not have been sealed properly, if at all. There are joints in the barrier, penetrations, where the plastic meets the wood and they leak if not well done.
Some houses need humidifiers, others don't; it's a function of air leakage, climate, and the amount of moisture being produced.
A newer house can be leaky, especially if you have air ducts in a crawl space or attic. If the construction quality isn't the greatest the vapour barrier may not have been sealed properly, if at all. There are joints in the barrier, penetrations, where the plastic meets the wood and they leak if not well done.
The Nest has nothing to do with it. Every house is going to be different in the Relative Humidity and same thing with Dew Point.
There is no perfect formula to not cause the house to be so perfect, that you do not see the glass stay below the Dew Point. You are always going to have warm air hitting glass at a cooler temp, even if it is a Triple Glaze. The only way to not have condensation on glass, is to keep the drapes open 24/7.
Makes sense. I noticed it in my kids room and we put cellular blinds in her room to keep it nice and dark but no air flows around them. I normally have heat set to 72 during morning activity, then it drops to like 58 through the day when no one is home, then back to 72 in the afternoon and then down to 68 overnight.
So what I'm hearing is this:
My house is newer but still leaks air a decent amount
Unless I keep all drapes/blinds open I will get some condensation
Furnace Intake from inside the house is okay on high efficiency models
Close up leaks, don't worry about a little condensation on the interior pane, install a humidifier.
Now to look into ouse humidifiers. I was going to buy and install an aprilaire 700 (not sure of model at this time, its been a year since I looked). Its a powered model that blows a fan across a pad into the plenum. Looked easy to install and can be installed on either supply or return. In my current configuration I will have to use return. Trying to take pics but app isnt working well so on desktop now. Pics incoming.
Air leaks are fine, as long as you do not have so many that it is like leaving the front door open. I went around to all of the electrical boxes on the outside walls, pulled off the stops around my windows and sprayed in DAP foam, which does not stiffen like the Great Stuff.
I also went and at the front door, had to place Felt weather stripping where there was a gap at the top, because of the house settling over the years, then used the weather stripping that is the Aluminum channel with the foam core and nylon outer covering. That helped a lot.
If your humidity stays low, even if say you boil a large pot of water on the stove and run the bath fans, or run the shower with hot water, your wood stove would be why you are seeing it dry out so much.
The Aprilaires are the most chosen unit for helping to bring the RH up. But you may never get it to stay around what mine or someone else's does.
The whole temp & humidity argument is one that some think that everyone else have their house too high for RH, if it is 68 for the temp and between 50-56. Same as if some people keep it down in the 30's for humidity, because that is what some website states.
I also went and at the front door, had to place Felt weather stripping where there was a gap at the top, because of the house settling over the years, then used the weather stripping that is the Aluminum channel with the foam core and nylon outer covering. That helped a lot.
If your humidity stays low, even if say you boil a large pot of water on the stove and run the bath fans, or run the shower with hot water, your wood stove would be why you are seeing it dry out so much.
The Aprilaires are the most chosen unit for helping to bring the RH up. But you may never get it to stay around what mine or someone else's does.
The whole temp & humidity argument is one that some think that everyone else have their house too high for RH, if it is 68 for the temp and between 50-56. Same as if some people keep it down in the 30's for humidity, because that is what some website states.
I don't have a wood stove. I'll check the weather stripping but I've already caulked around all the windows and replaced most weather stripping. I also great foamed in between door jam and rough openings where I could.
I've been battling bad construction from 2001 since I bought this house 2 years ago.
That period was when they were still putting up homes that were built as fast as they could, with cheap labor.
I love our 78 year old house. I would not trade it for anything new.
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