Fall is in full swing here in the mid-Atlantic region. Although we still may have a balmy day or two in the forecast, daily temperatures will continue to drop as winter approaches and the hours of sunlight each day get shorter. As you perform exterior maintenance items like putting away garden tools and hoses, mulching flower beds, and trimming back spent perennials, give a bit of attention to your windows.
Late-fall is a good time to remove your screens to clean the exterior of your windows and sills before winter sets in. Most window screens, such as for double-hung and slider windows, are located on the exterior of the window. One exception is casement windows, where the screens are mounted on the interior.
For exterior screens, removing them before washing windows make the job easier. It’s also a good idea to hose off or vacuum all screens, inspect them for any holes, tears, or other damage, and repair as necessary. Store them in a safe place away from foot traffic, such as a garage or basement. It’s also a good idea to label each screen with pencil or chalk to be replaced back in the proper window in the spring.
Once your cleaning is complete, should you reinstall your screens for the winter? There are a couple of reasons you should not keep your screens on your windows over the winter, but instead store them until spring.
If you have single-pane windows, removing the screens and replacing with storm windows is a must. Otherwise, a single pane of glass is very inefficient at keeping the heated air inside your home and the cold air out. A storm window traps a pocket of air between it and the window, creating a thermal barrier to improve the window’s insulating properties.
While Maryland, Virginia, and Washington DC aren’t prone to major blizzards every winter, we still get our share of snow storms. During a storm, wind can blow snow that can get trapped between the screen and the window. That trapped snow can cause damage to your window frames and sills, as well as potentially damaging the screen mesh from the weight of the snow. Another reason to remove window screens is aesthetics. Windows generally look more pleasing from the curb when the screens are removed and the glass shines.
But one of the most important reasons to remove window screens in the winter is improved solar heat gain. Solar heat gain is the amount of solar energy that penetrates a window. For windows that face the sun (primarily south and east facing windows), solar heat gain is desirable in the winter because it helps to heat up a room simply from the energy from the sun. If a window screen is left on a window, it reduces the amount of solar energy that reaches the glass.
The Midcoast Green Collaborative tested this improved solar heat gain theory with interesting results. Researchers placed three pieces of dark soapstone in a room near a south-facing window – one in the shade, one in direct sun coming through the glass, and one in sunlight filtered through a window screen. Measuring the temperatures with an infrared thermometer, the stone in the screened window was eight degrees cooler than the stone in direct sunlight through the window. Their results indicate that screens block about 30-40% of the heat that would otherwise enter windows without screens.
So whether you remove your window screens for aesthetics, to prevent snow build-up, or to install storm windows, the benefits of solar heat gain should make the decision easy. Increased warmth in rooms receiving direct sun will help save money on heating bills and reduce the workload of your heating system.