Winter Window Woes
Did you know that extreme winter cold can place undue stress on your house? Consider your windows. A graphic example of the effects of extreme cold can be seen on the old single-glazed, metal-framed windows in many older homes. During a really cold night, these windows will often frost right up. While wonderfully artistic, and fun for kids to scratch their names into, this does render the window practically useless: frosted over and frosted shut.Most windows will exhibit varying degrees of the same effect. Even some new windows will sweat heavily or frost up. Let’s look at the root causes, and suggest some solutions.
Whence the Water?
The water forming on the window is due to condensing moisture in the house air. Vapour that comes in contact with the cold surface of the window will cool down and form water droplets. If the windows are very cold, the droplets freeze, shortly after forming on the window, causing ice to build up.
Waylay the Water
How can the problem be corrected? There are two ways: remove the moisture from the air in the house, and warm up the interior temperature of the window glass and frame. Removing moisture form the air is a challenge. The best we could hope for, short of moving to Arizona, is reducing the interior moisture level to a minimal level. Do this by turning down, or off, your furnace humidifier, ensuring your clothes dryer is properly vented, using kitchen and bathroom exhaust fans when cooking and showering, and even opening a window periodically when things feel “stuffy”.
The second strategy is to warm up the surface temperature of the window glass and frame. If the window is old, it may be drafty. This will be apparent - cold air whistling around the edges. Luckily, replacing or improving weather stripping is a relatively easy DIY project that can often solve a draft problem. If the window has only one pane of glass between it and the outside, install a storm window. This will warm up the interior pane. Of course, the frost will want to form on the inside of the storm window anyway. It won’t if the space between the windows is vented to the outdoors (remember the holes in the bottom of old storms and the little wooden flap that covered them?) With a newer double-glazed window, unless it’s poorly constructed or very poorly installed, the glass and frame temperature should be reasonably warm.
The trick now is to assess where the heat source is in the room. In a perfect world, the heat for the room is delivered at floor level right below the window. The idea is that the warm air, either from a furnace register or off a radiator, washes up the window keeping the glass and frame nice and warm – thus eliminating, or at least reducing, condensation. A related problem in many homes is window treatments. California shutters look great and can block out light, but when closed, they also block warm air from reaching the window, leading to condensation in cold spells. The solution is to open up the louvers, or open the shutters.
Courtesy of Carson Dunlop & Associates. Copyright 2010 Carson Dunlop & Associates Ltd. All rights reserved.
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