Home & Garden

Window condensation cause of extreme cold?

  • Last Updated:
  • Jan 11th, 2019 6:19 pm
Deal Addict
Aug 25, 2005
4725 posts

Window condensation cause of extreme cold?

It hasn't been an issue for me in years past but almost every window on the ground and 2nd floor has an insane amount of condensation right now. To the point where it's pooling on the bottom window sill.

Is it due to the extreme cold? Seems unlikely all my windows decided to fail simultaneously.

The ecobee3 is only registering 34% humidity on the ground floor.
35 replies
Sr. Member
Mar 28, 2011
653 posts
Yes it's too cold outside

Even 34% humidity is too much as the cold air near the windows cannot absorb the moisture

Drop your humidifier down to 20% and it should be good but then you will have dry skin...I still keep mine at 35%

I just keep wiping the windows in the morning and at night for the last couple of weeks as it keeps hovering around -20c
Deal Fanatic
User avatar
Dec 28, 2007
6163 posts
Same problem with our house right now and I have my humidifier shut off. It's -28C outside.
Sr. Member
Mar 19, 2013
695 posts
Prince Albert, Sask.
Same for us. Been very cold the last week. Have the humidity down to 16%. Helps with the condensation, very dry and staticky. Will have to pump in some humidity. Weather is to improve this week.
Deal Addict
User avatar
Feb 25, 2015
1042 posts
York Region
Wipe the water in the morning and open your blinds, shutters, drapes for air circulation and lower the humidity like everyone is suggesting. When this cold snap first happened, it was like Niagara Falls on my windows but now that the humidity is closer to 20%, the condensation is gone.
Deal Addict
Aug 22, 2009
1381 posts
I open my shutters or curtains in the morning.

Master Bedroom I have a floor fan that I blow on the window- does the trick.

I’d rather have condensation on my windows rather than dry skin and/or nose bleeds
Deal Addict
User avatar
Feb 10, 2006
3136 posts
dropped the humidity to 30% and still seeing the issue slightly. A good wipe in the morning and at night is keeping the issue at bay.

Lets hope the extreme cold is done soon
Deal Addict
User avatar
Aug 29, 2001
3032 posts
Water loo
I used to have black mold from all the moisture from my builder class windows, I since replaced my top floor with triple glazed after market windows. No moisture on them even on a -26C night.
My first floor windows are still stock and very moist, make sure the furnace vent (if you have forced air) is blowing air past the window and I have towels on the bottom now to catch the moisture.
May 7, 2016
384 posts
A couple of pics to explain this issue:


Assuming you have your thermostat at 21 degrees, humidity at 34%, the inside pane of your window just has to be at 5 degrees to start condensing water. Considering it has been less than -20, it is easy to guess your windows are at least at 5 degrees and therefore they start condensing water:

Deal Fanatic
Dec 11, 2008
9591 posts
Yes normal. We keep the humidity at 45% in the winter due to hardwood floors and to avoid dry skin.

We just wipe the windows and always keep the blinds lifted and open about 6 inches from the sill so the air can hit the glass.

You really need to get the air to hit the windows as we have 2 windows that are obstructed by furniture and those are the worst but the others are pretty good.
Deal Fanatic
User avatar
Feb 15, 2005
5383 posts
It looks like we're all owners of standard double pane windows. :D

The triple panes in my rental condo and my parents' place don't have any issue with humidity set at 40% all the time.
No external links in signatures - Mods
Deal Addict
Oct 12, 2006
1633 posts
During our cold snap (-20 to -30), I shut off the humidifier and according to my sensors, humidity hangs around 20 % (wake up with dry mouth). I still have a couple single pane windows at my place.
During regular winter temp, I keep it around 35% which still feels weird coming home to (only fixed my humidifier this year).
Deal Addict
May 23, 2009
2179 posts
rf134a wrote:
Jan 2nd, 2018 11:48 am
It looks like we're all owners of standard double pane windows. :D

The triple panes in my rental condo and my parents' place don't have any issue with humidity set at 40% all the time.
I agree. My place ranges from 38-42% and no condensation issue on windows(triple panes).

My previous double pane windows were always sweating a lot once I go above ~32% in the winter. I used towel along the window jamb on extreme cold days and lowered to less than 20% to keep it manageable.
May 22, 2009
58 posts
Capital City
Had some frost/ice on the bottom of the windows yesterday so I grudgingly turned down the humidity. I have plastic window frames, so I'm not as worried about mould, am I wrong? I searched for a while to see the detriment to ice on the windows, but couldn't find anything. I have double pane windows of indeterminate age (greater than 20 years I'm sure) that need new caulking, maybe the ice is indicative of greater issues?