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Iced up brand new windows

This fall, we installed new windows in our house (the house was built in 1960, bungalow). Ever since it turned colder (this week it's -40C with the wind chill), the windows have iced up on the inside and are actually dripping and freezing. Our big picture window has even cracked...brand new window!! We thought our old windows were bad, these new ones are way worse. I wipe them constantly but there is still an ice build up. What can we do?

Re: Iced up brand new windows

I'd call the manufacturer. There may be a manufacturing defect, such as losing the inert gas between the panes which provides some of the insulation value. Some manufacturers will send out a rep to determine whether it is a manufacturing defect or an installation error.

One common mistake when installing windows is to fasten them too securely to the framing. The frames need to be able to "float" a little bit to allow for expansion and contraction. This could be why the picture window cracked. Maybe there was some water infiltration which froze, putting pressure on the frame causing it to crack. Improper installation is rarely covered by the manufacturer's warranty.

If you installed these windows yourself, you might be able to get the dealer to come out and take a look.

If the installation is OK, the manufacturer should replace the panes. Most new windows can be repaired by just replacing the pane; there isn't much that goes wrong with the frame.

On the other hand, your house may now be TOO tight. A house needs some "breathability" otherwise the indoor air will become extremely humid and stale. It may be that your old windows were drafty enough to provide the necessary ventilation. You may have to introduce forced ventilation -- something like an exhaust fan on a timer and a fresh-air intake into the cold-air return of your furnace. Set the fan to run a couple of hours a day to exhaust air from your house. I've heard that the "ideal" humidity indoors is around 40%.

Yes, this seems to be inefficient, but at some point efficiency has to take a back seat to indoor air quality.

Re: Iced up brand new windows

I would say there is a leak somewhere. Let us know what happens.

Re: Iced up brand new windows

Odds are that the condensation is due to a relative humidity inside the home which is simply too high for the outdoor temps. The colder the outdoor temp, the more likely condensation becomes.

If you have a humdifier on your furnace, turn it down a ways.

Make sure that you have exhaust fans in both the bathrooms and the kitchen which exhaust to the great-out-of doors.....and that you use them.

Also......make sure you have at least one quality carbon monoxide detector in the home. (A digital unit such as a Nighthawk and not some cheapy $10 model) If you have a leak or obstruction in the exhaust flue of a gas or oil-burning appliance/furnace/water heater/fireplace...........that exhaust will contain much moisture along with the CO. IOW, the extra moisture you see on the windows may be related to such a leak and an indication that there is also CO in the air. CO kills and is not something to be taken lightly.........as if it can't/won't happen in your home.

If you have blinds or similar in front of these windows, that will also increase the likelihood of condensation. That because the warm air cannot circulate as freely behind the blinds...to warm the windows, which helps prevent condensation.

The picture window *may* have cracked because it was fit too tightly in the rough opening. It is not that uncommon to see these windows fitted a bit too tightly along the header (the top edge). If the header settles a bit, that pressure/weight then rests upon the window and can easily crack it. I would contact the manufacturer regarding that window and would expect them to remove the interior casings around inside the home to check the fit. If it's too tight, then it's time to call the contractor who installed the unit.

(However, if you replaced two or three smaller windows and replaced them with one pig picture window (and simply removed the structural support between these smaller windows in the process), then header sag should be expected. This sort of "reconfiguration" would usually/frequently require some extensive & expensive restructuring of the header area. All too often folks think they can get away without doing that, but it seldom works.)

Re: Iced up brand new windows

Same effect as condensation on a tall cool drink on a hot day. Warm, moist air hits the cool glass; as the air cools off its ability to hold moisture drops so the water vapor condenses on the glass. When the glass is below freezing it turns directly into frost without passing the liquid stage.

(There's a scientific term for this, going directly from solid to gas and from gas to solid, but I just can't remember what it is right now.)

Best option is to try make sure your indoor humidity is under control; I think 40% at 68-72 degrees is considered optimum for healthy living. Higher humidity encourages mold growth; lower humidity dries out your skin.

I imagine that with exceptionally cold temperatures (well below zero) you could see this effect even on double-pane windows. I've heard that you can reduce the cooling effect of a window by using floor-length curtains that actually touch the floor. This blocks the convection currents, locking the cold air behind the curtain. Don't know if it works or not, never tried it myself.

Rehabber Wannabe
Re: Iced up brand new windows

I'm experiencing the same type of window issues as Char described, but are in a house only 7 years old. I cannot believe the amount of ice building up on the inside of my windows. My wife and I have lived in 100 year old Chicago 3-flats with original windows that haven't had this kind of problem. After reading all the responses, I think it may be humidity level related, but have tried most of the suggestions (e.g. lower humidity setting, raise blinds, and even tried running ceiling fans) without success. I'm not sure if a picture helps pinpoint the issue, but I've posted a picture of the ice build up on occurring on all the many casement windows throughout my home (worse on 2nd floor)...

Appreciate any additional advise

Re: Iced up brand new windows


Yikes! That's some serious condensation.

I'm gonna guess from here that the problem may not totally be a result of too high of humidity level, but may be multi-faceted.

Besides too high of a RH, I'm wondering if the installer bothered to properly insulate between the window jambs and the rough opening. If he/she didn't then cold air can readily enter this space which results in much colder window jambs, sill, etc...which then encourages condensation. You can both inspect & retro-insulate these areas by removing the interior casings from the windows.

Also, if the window seals aren't all they should be, then cold air leaks past those and cools things down far below where they would be if the seals were tight. I guess it's the prescence of the frosty appearance of alot of that condensation that makes me think there is air-borne moisture meeting/co-mingling with a cold air flow.

There is also the possibility that this excess moisture is coming from a partially blocked exhaust flue or hole/crack in exhaust flue of a gas-fired or oil-fired appliance. These fuels contain alot of water vapor in their exhaust. Make sure you have at least one quality digital read-out CO detector in the house. CO poisoning is nothing to fool around with. It will make you sick and perhaps kill you, but you won't even smell it.

Excess moisture can come from some sources that most folks don't think about...such as aquariums, firewood stored inside, plants (if you have alot of them), a clothes dryer allowed to vent inside the home (or with a leaky exhaust pipe), etc. And let us not forget an unheated dirt crawl space without a layer of plastic down on it and sealed around the edges.

If the home is tight....once this excess moisture is present it can take quite some time or even a dehumidfier to get things back under control. While 40% feels nice to humans, that high of a RH can readily lead to condensation in a cold winter area such as Chicago. (I'm about 2 1/2 hours, pedal to the metal, NW of there.....and dang it's cold here right now.) 25-30% RH is probably closer to where you need to go when temps get down around 0-ish to avoid condensation.

What kinda temps are you maintaining inside this house? Too cool is not a good thing.

Rehabber Wannabe
Re: Iced up brand new windows


Your feedback is very helpful and much appreciated. I'll do some checking around the house for some of the potential causes you noted. As for the temp in my house, we usually keep it between 67-70 degrees.


Re: Iced up brand new windows

Yep .... agree with goldie's comments.

Last week while in a deep freeze ( -30 with 40 mph winds ) I had been doing some work in a building where 4 double pane vinyl sliders had thick ice such as yours .... the other fixed pane windows only had the wet condensation.
This indicated there was too high of humidity inside the space and the sliders had air leaking ( due to the winds ) past the seals. With the sub zero temperatures this caused the condensation to freeze only on the sliders while the fixed panels weren't experiencing the ice build up.

It looks as though the window pictured is an awning or hopper type of opening window? If so I've seen the compression type of seal on these windows lose the spring back and not seal as well. Also if the window panel dosen't close as tightly as it should either from the mechanisim or the panel is misaligned will also leak.

Since your home is only 7 years old it's more tight compared to the older homes. The older leaky homes will actually exchange the air because of being leaky. This means the warm humid inside air will leak outside and cold drier outside will replace it ..... somewhat controlling the humidity.
If you also have a high efficient direct vent heat source these don't use inside air for the combustion. Compared to mid efficient or open fire places that use inside air for combustion which removes some of the humidity from the living space.

It's not uncommon with newer tighter homes with direct venting heating equipment to experience higher humidity inside.

So the humidity inside should be lowered as the outside temps drop.
For example .... with the temps here hovering around - 18 F the humidty should be around the 30 % mark.

2 cents worth.:)

Re: Iced up brand new windows

I'll add one more comment concerning vinyl windows since Canuk brought it up.

Not all vinyl windows are created equal. Some of the hollow extruded frames are filled with insulation and some are not. Those that aren't will chill far more than those which are. Quess which ones are more prone to condensation problems.

The upside to vinyl windows is that they won't rot from the condensation. ;)

Blue RidgeParkway
Re: Iced up brand new windows
canuk wrote:

It looks as though the window pictured is an awning or hopper type of opening window?

Its a casement window, see crank, and Rehabber Wannabe said so, fyi. Canuks points still valid about the weather stripping and if the operable sash isn't lined up square to the window opening and if it is not hanging plumb sometimes the hinge mechanism (openers) need adjustment and the screws that secure them to the sash and frame can losen over time. I used to have one window in particular that the top mechanisim was always losening so the lower one would bear all the weight, bend and the window not square or tight because the sash receiver was stripped. Finally got that set and no more problems, except had to replace the weather stripping because it was all deformed from the sash not closing right previously.

Rehabber Wannabe wrote:

.I've posted a picture of the ice build up on occurring on all the many casement windows throughout my home (worse on 2nd floor)...

Appreciate any additional advise

Tackling this problem in the extreme temps might not be practical, definately a to do project when the weather breaks. In the mean time you might try drying the window area on a warmer sunny day and temporarily install some of those interior storm window kits with the double sided tape on the outside edge of the window trim moulding (near the wall edge) and shrinking the film with hair drier to hold you over until spring and keep the area free of warmer air moisture indoors/condensation to prevent rot and finish problems and fix it in the spring.

warmer air convection upstairs. warmer air holds more absolute moisture. also likely bathroom/showers upstairs. vent moist air outdoors during baths/showers and keep bathroom door closed run fan longer after finished.

recirculating range hoods also notorious (instead of exausting). clothes dryers not venting outdoors or having lint collections in the vent so can't properly vent notorious moisture loaders indoors.

can get a measuring device that indicates relative humidity can find combination display thermometers that also have RH. Might want to invest in a few, place in a few rooms..


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