Window condensation

[ollie76]

Morning folks,

I've been getting a little window condensation lately with the heat on and I was looking for some tips.

I'm running my air exchanger all the time and it doesn't seem to be helping so I don't think it's an air issue. I've noticed that the condensation isn't on most of the windows......It's only present on the crank out windows (the ones that open). All the fixed windows are dry.

So....I'm thinking the cold air is leaking in at the bottom and making that part of the window colder than it should be. Then the warm air from the house is condensing on that cold glass.

These are double pane, crank out windows. I'm assuming I need a little sealing on these things. Any recommendations?

 

[yeldogt]

Condensation is all about humidity and dew point -- hotter air can hold more ... the dew point is the temp this water will condense. Relative humidity increases as temps fall.

You can reduce inside humidity or increase temps.

It could be leaking -- it could be placement or the RH in the house could be elevated.

This ties into your other thread. While air exchangers can effect humidity they are there to exchange air .. that's what they are for. They can only use the outside air to reduce internal humidity and that's not going to be 1:1.

You are also exchanging a lot of air if it's running 24/7 at whatever efficiency your unit operates ....

 

[ollie76]

Well how can we explain how, like I show in the pic, the LH window is consistently dry while the window on the RH usually has a strip of condensation on the bottom?

The RH window opens......the LH does not. The glass on the door in the middle also never has moisture on it.

 

[lakeroadster]

Got an infrared thermometer? That will likely show a temperature difference which may explain the condensation variance.

 

[yeldogt]

The window on the left w/o the condensation is in the sunlight -- it's warmer.

Can you feel air leaking ?

Thermals occurs inside and outside as well as inside the widow

-- take a look at a snow covered car ... see where the condensation occurs inside the vehicle. Typically just above the snow line outside .... why not just bellow?

You would need to check the humidity inside -- is that a door you use often w/ snow covered boots? more moisture in that location

 

[Falcon67]

If they are aluminum frame, that's what they do IMHO because the frame conducts outside cold. If the house is "tight" the problem is worse. The fix - such as it is - would be de-humidify the house or replace the windows with vinyl.

 

[ollie76]

The window on the left w/o the condensation is in the sunlight -- it's warmer.

Can you feel air leaking ?

You would need to check the humidity inside -- is that a door you use often w/ snow covered boots? more moisture in that location

There's actually no sunlight on that left window....it just looks like that. Both of those windows receive almost no sunlight.

Yeah, I can definitely feel air leaking.

So yesterday I bought 4 little cheapy hygrometers and placed them around the house and let them sit for a few hours before checking them. It seems that the RH% hovers around 45% in all areas fairly consistently. I placed one in the main living area, one on the back door, one upstairs right next to the air exchanger humidity dial controller, and one in the bedroom next to a window I suspect is leaking. The highest I've seen so far is about 55% which was right next to the upstairs window.

We do not use that backdoor very often. It's almost never opened in the winter. I placed one of the hygrometers right on that back door and the RH has been around 45% since yesterday.

 

[yeldogt]

Leaking air will do it -- and snow covered ground will produce high humidity levels around a house. It why people can end up with mold in attics w/ soffit ventilation in winter time.

 

[Bluevista]

Leaking air will do it -- and snow covered ground will produce high humidity levels around a house. It why people can end up with mold in attics w/ soffit ventilation in winter time.

That's why you always install roof fans with humidistats and thermostats, required by code in a lot of places.
No or undersized soffit vents equals ice dams.

 

[yeldogt]

That's why you always install roof fans with humidistats and thermostats, required by code in a lot of places.
No or undersized soffit vents equals ice dams.

Or do away with it all ..... closed attics and crawl spaces. I never vent -- even my place in VT.

 

[larry_g]

Do you typically have the blinds closed? Try raising them up. Also try setting a small votive type candle there to see just how much draft is there. For testing purposes try taping the seam on the inside to seal all the draft off if necessary. That could confirm your hypothesis of a bad seal.

lg
no neat sig line

 

[justinjoyal]

yeldogt laid it out for you. [emoji106]

If the window is leaking it can cause condensation.

I would advise you don’t constantly run your exchanger. As explained in your other thread, set the onboard switch to REM and adjust the humidistat to the right RH%.

What are the exterior temperatures where you’re at these days? I see snow on the ground so I assume colder temperatures. Try getting a interior RH closer to 35-40 and see if that helps.

 

[MadMechMaster]

Yes, lower the RH. I keep backing it down until the cats give off sparks, then turn it back up a bit. 35-40% seems right.

 

[Showkey]

It’s cold out and going to get a Lot colder for many in the next few days...........so window condensation will be the topic once again:

http://www.newsminer.com/features/o...cle_eab0d3da-5805-11e3-ab31-0019bb30f31a.html

https://www.hvac.com/faq/reduce-condensation-windows-surfaces/


http://www.cswindows.com/windows/2016/12/windows-in-the-winter-condensation/

https://www.familyhandyman.com/wind...void-and-remove-window-condensation/view-all/

http://www.remodeling.hw.net/products/windows/practical-guidelines-to-combat-window-condensation

 

[Lelandwelds]

Yes, lower the RH. I keep backing it down until the cats give off sparks, then turn it back up a bit. 35-40% seems right.

Got an infrared thermometer? That will likely show a temperature difference which may explain the condensation variance.

What is a cat?

If a Fluke infra red can spot the coldest beer in the icechest, it can tell if one window is slightly colder than another. It is possible the thermal break is less perfect in one. They may not have the same glass coating or argon fill.

Operable windows often leak heat. Take its temp.

 

[old__man]

What is a cat?

Sort of like an indoor lawn ornament. Says meow a lot.

I think the comment was referring to the fact that when the air is really dry you get a lot of static electric shocks indoors. Thus the ***** cat giving off sparks when it moves.

 

[MadMechMaster]

Yeah! If you don't have a cat, sweaters or blankets will do.