Window frost forms when a pane of glass is exposed to below-freezing temperatures on the outside and moist air on the inside.  (Photo: Contributed)
Window frost forms when a pane of glass is exposed to below-freezing temperatures on the outside and moist air on the inside. (Photo: Contributed)

Windows frosting and icing

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If you have one of those Okanagan homes with single pane double slider aluminum windows you can tell that it is really cold outside because your windows frost and ice up.

These windows were very popular in new home construction in the seventies and eighties because they were economical. Unfortunately they offer little thermal efficiency. They are a bit cumbersome to open and close. A typical bedroom window consists of five separate windows that ride on two aluminum tracks, 3 – 4 inches apart. If you have ever taken them apart to clean them you wish that you’d have numbered them before you started and have made a commitment to have somebody else clean them next time.

They leak air. The warm moist air from your home can easily escape out through spaces between the windows. The warm air deposits its moisture onto the cooler surface of the glass, kind of like how a frosty cold pop behaves in the summer.

When it is -10 Celsius outside the temperature of the inside window is only about 4 degrees Celsius. At 4 degrees, it doesn't take much moisture to cause condensation on the surface of the glass. The temperature of the outside window is going to be well below freezing so the moisture deposited on the glass is going to freeze.

So what can you do about it? There are a few things you can do to help prevent moisture from gathering on your windows. First, you can attempt to increase the temperature of the windows to a mark above the dew point. That means you have to heat up both the windows. Not a practical solution.

Second, you can attempt to block the warm, moist air from reaching the glass by installing a plastic window covering. The plastic film will help to keep inside moisture away from the windows. It is unsightly and not practical if you need to open a window or kitty likes to climb walls.

You can keep blinds and curtains open to assist in controlling the inside condensation, but that won't do much for icing-up the outside window.

Lastly, you can install brand new thermal efficient windows. They are going to cost a few bucks but your home won’t leak as much, they will open and close easily and if you’re the guy who has to clean them, you’ll be thrilled.

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About the Author

When you need advice or guidance with DIY home improvement and repairs, Hugh Cairns can help you with the answers.

Home improvements can be rewarding, turn your home into a nicer more comfortable place to live, and increase its value.

Whether you are renovating your kitchen, converting a loft, giving a room a lick of paint or making improvements to your home’s energy efficiency, this column is here to guide you with useful information and key things to remember.

Do you have a renovation question or concern? Please feel free to send Hugh your questions. Contact him through www.subject2homeinspections.com

The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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