I'm having a problem with condensation and ice build up on new double hung windows. Both windows are dual-pane, low-E, argon with fiberglass frames. Both are in bedrooms, one only has a shade covering it at night, and one has no window covering at all.

My relative humidity in the house is 37% now, with an outside temp of about 0 F. Condensation will start at outside temps as low as 25 F. As winter comes on, the condensation gets worse, until water is pooling, and then thick ice forms.

The condensation only occurs at the operable edges (so bottom and middle for a double hung window), and only on the inside (house side) of the glass. The windows were installed a year ago, and are the only dual-pane ones in the house (all the others are triples). The triples show slight condensation in the mornings, and then it goes away. These 2 windows have heavy condensation ALL the time, regardless of the temp inside the house.

I have a separate combustion air intake for the furnace, the humidifier is turned down to 40%, and I run the exhaust fans for about an hour after a shower. I am currently managing the problem by blowing a fan at each window 24/7. I can't believe that is the only solution! The window manufacturer says it's just my relative humidity levels, but this level of condensation is excessive, and ice is just unacceptable!

Any suggestions? Solutions??

 

Bedrooms always have higher humidity since we exhale humid air from our lungs. In a northern climate triple pane will always perform better than double pane, so you would be wise to change out the glass in your new windows and curse out the salesman you bought them from. Why have all triple pane except for a couple windows?

There are plenty of threads in this forum that talk about ice on new windows so you can find good advice in them. And, yes, the bottom line is reduce humidity, but in your case, triple pane would help. You can always put plastic over the windows (interior side) in the winter time to act as a vapor barrier as well.

 

one of the bedrooms doesn't have anyone sleeping in it, and the condensation is constant, whether the room has been occupied or unoccupied for long periods.

the double hung windows were only available in dual-pane, so no choice there. I used to do the plastic sheeting in the winter, but my frames don't have an easy shape to get a good seal. Besides I always pull off my paint along with the tape in the spring!

I haven't seen any posts anywhere that talk about ice on NEW windows, with moderate or low humidity levels. I'll have another search through the forums.

Didn't know I could just replace the glazing... I'll look into that too - thanks!

 

You don't have low RH readings with a 0 outside temp. You need to reduce the RH like x sugested.

 

I hate to be the one to suggest this, but the problem could be a poor installation job. Especially if it is only on these windows. There are usually air gaps between framing and window frames, that space needs to be sealed/insulated. It may seem like a minor issue in a mild climate, but at 0 deg it could be a major problem.

 

Here is one from about 3 weeks ago.

http://forum.doityourself.com/doors-...w-windows.html

Some vinyl windows have sash frames that lose a lot of heat, which is detrimental to the temperature of the glass at the perimeter. Some aren't glazed solidly on the outside which allows cold air exchange around the perimeter of the glass, making the edge of the glass colder than it could/should be.

And it's obviously too late now, but there are PLENTY of windows available that offer triple pane as an option in a double hung window. Being up north, I'm quite surprised window dealers/salesmen don't view that as being a minimum standard.