Shading Your Windows

Now it’s time for the Idaho Power energy efficiency tip of the week.

Looking for another way to keep the summer heat out of your home? About 40 percent of the unwanted heat that builds up in your home comes in through the windows.

In warm weather, shading windows from the outside with solar screens, window tint or awnings, for example, helps keep the sun’s heat from coming into your home and is generally more effective than shading them from the inside.

Solar Screens

Solar screens are versatile window coverings that offer protection from the sun’s heat, ultra violet rays and insects. Regular window screens keep out bugs, but they can’t block out the heat or ultra violet rays. Solar screens are available in many styles, colors and types for both indoor and outdoor installation.

Window Tinting

Window tinting is a plastic film that is applied directly to the glass on the inside of the windows, and much like tinting on car windows, helps block ultra violet rays, provides increased privacy, reduces glare and prevents fading of indoor furnishings.

Window tinting is available in many different colors and reflective options and is flexible enough to allow you to choose how much light or UV rays you want to block from your home.

There are two main types of film: sun-control films and combination films. Sun-control films are optimal for warmer climates because they can reflect as much as 80 percent of the incoming sunlight. Many of these films are tinted and can reduce light transmission as much as they reduce heat, which can darken the room.

Combination films allow some light into a room but they also let some heat in and prevent interior heat from escaping. These films are best for climates that have both hot and cold seasons. Investigate the different film options carefully to select the film that best meets your needs.

Do not place reflective coatings on south-facing windows if you want to take advantage of heat gain during the winter.

Awnings

Awnings are another way to shade your windows from the outside. They can be retractable or fixed. Properly installed awnings can reduce heat gain on southern-facing windows by up to 65 percent and up to 77 percent on eastern-facing windows. According to Weather.com, “Maintaining a gap between the top of the awning and the side of your house helps vent accumulated heat from under a solid-surface awning. If you live in a climate with cold winters, you will want to remove awnings for winter storage, or buy retractable ones, to take advantage of winter heat gain. The amount of drop (how far down the awning comes) depends on which side of your house the window is on. An east or west window needs a drop of 65 percent to 75 percent of the window height. A south-facing window only needs a drop of 45 percent to 60 percent for the same amount of shade. A pleasing angle to the eye for mounting an awning is 45 degrees. Make sure the awning does not project into the path of foot traffic unless it is at least 6 feet 8 inches from the ground.”

With information from:

http://www.makeyourhomeenergyefficient.com/energyefficientwindowcoverings.html

http://www.progress-energy.com/custservice/flares/energyhome/windows.asp

http://www.weather.com/activities/homeandgarden/home/hometips/troubleshooting/ac_without.html

U.S. Department of Energy, U.S. Environmental Protection Agency