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Condensation and Ice Buildup on Windows in Extreme Weather

IcedGlass iStock edit2181582021Our extreme cold weather can wreak havoc on our daily living. Near the top of that list is the nuisance of ice and condensation build up on our windows. We’re here to tell you that it’s something to attend to but not that uncommon in freezing temperatures.

With extreme cold outside temperatures, beads of moisture or condensation can accumulate on the inside glazing of your windows. Then a layer of frost or ice develops on the glass or in the corners near the window frame, it’s natural to worry. What are the causes, and if your windows have this problem, what can be done?  

The primary culprit for this condition is interior humidity levels, lowering your humidity will reduce moisture and sweat or ice build-up on your windows. When ice forms on the insides of windows, it is cold air from the window itself or leaking around the window frame coming in contact with the moist air in your home and freezing.

Contrary to our common sense, don’t close heavy drapes during freezing temperatures as they only serve to trap more moisture against the cold glass. Be sure all your kitchen, laundry and bath vents are working properly and vented to the outside. Running your ceiling fans, reverse setting (clockwise and slowly) to pull warm air up, is also a helpful to keep air circulating in the room.

The Right Humidity

One key way to stop condensation forming on your windows is to pay attention to your Indoor humidity levels in winter. The humidity level of your home needs to reflect the outdoor temperatures. If you have sweaty or frosty windows, your indoor humidity levels are too high. A cold day such as 10 degrees means the humidifier recommended setting would be for 30% relative humidity. Most people aren’t aware that unless they have n “automatic” humidifier that comes with an outdoor temperature sensor, they need to change the setting of the humidifier based on the outdoor temperature. You’ll find this chart from buildingsciencesllc.com helpful.

Relativehumidity M

Whole House Humidifiers

Most of us are familiar with the benefits of small portable humidifiers. Portable whole house humidifiers are much larger to improve the air quality in a larger area. If you use one, we suggest you buy a hygrometer, also known as a humidistat from a hardware store to measure the humidity level accurately.  Alternatively, you can opt for a whole house humidifier that installs directly into your cooling and heating system to ensure that your indoor air quality remains consistent year-round.

In a cold snap like ours, your windows get colder than ever and cold air can’t hold as much moisture as warm air, if there’s too much humidity in your home – yep – frosty windows.

Old Windows vs New

If your windows are old and you’re experiencing condensation and frost buildup during severe weather, it could be that there is poor or no insulation around the window frames, the glass may not be well insulated or the seals are broken. Windows do wear out and need to be replaced.

Today.comWinterwindow copyIf you have replaced your old windows with new ones, you might see more condensation. Frankly, condensation on new windows is a sign that your windows are doing their job and holding heat inside your home. The dual pane, gas filled, thermal spacers and weather-stripping all are designed to maintain an incredible temperature difference between the inside and outside. New windows are also rated for condensation resistance (CR). The difference is that your old drafty windows allowed cold air in and warm air to flow out, reducing the humid air inside the house. The new energy efficient windows minimize heat loss from your home in winter. Signs of condensation or frost is again, likely due to high humidity.

Parting thoughts. If you do get ice build-up try all of these remedies, reduce the amount of humidity in your home, pull back the drapes or open the blinds, turn your ceiling fans on in winter mode and let the warm room air melt the frost or ice. Don’t try to scrape your windows as you may damage the glazing or the frame.

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