To Shade or Not to Shade Your Windows, and How This Decision Affects Heating and CoolingPublished on: September 23, 2014
Window coverings aren’t just for decoration; they can also help you save money on heating and cooling if you use them properly. Consider some of the most effective window treatment options for reducing heat loss in the winter and heat gain in the summer.
For south- and west-facing windows, awnings can reduce solar heat gain by 65 to 77 percent. Water-repellant awnings made of acrylic and polyvinyl laminates are treated to resist mildew and color fading. You can choose a standard awning to cover a single window or seek a custom-made version to shade the entire west or south side of your home.
Properly designed roof overhangs can effectively shade south-facing windows from the summer sun all day long. Then, in the winter, the sun can still shine in the window and provide natural warmth thanks to its lower angle in the sky.
It’s fairly straightforward to incorporate overhangs in new construction projects. Design considerations include latitude, climate, and window size and type, among other things. However, it can be quite difficult or even impossible to add an overhang to an existing home. In that case, awnings and patio covers are good alternatives.
Vertical or horizontal Venetian blinds are effective at reducing summer heat gain by blocking direct sunlight from shining into your home. The slats provide flexibility, allowing you to aim the blinds so light bounces off the ceiling, offering natural light without the heat of direct sunlight. The ability to change the angle of the blinds lets you block more or less light as needed. When completely closed over a south- or west-facing window, blinds can reduce interior heat gain by 45 percent.
The ability of a drapery to reduce heat loss and gain depends on the material’s density, fabric and color. In the summer, fit windows with medium-colored drapes featuring a white plastic backing. Close the drapes over the windows during the day to reduce heat gain by 33 percent.
In the winter, choose heavy, tightly woven drapes for your window coverings. Open them up in the day to let the winter sun naturally heat your home. Then, close them at night to improve window insulation and reduce heat loss by up to 10 percent.
Window shades are a simple, effective way to improve heating and cooling efficiency. As with drapes, lower the shades during the day to reduce solar heat gain in the summer as well as at night to reduce heat loss in the winter.
For the greatest efficiency possible, use shades with a white reflective side and a dark heat-absorbing side. You can reverse the shade’s direction in different seasons, keeping the white reflective side facing the exterior in the summer and the interior in the winter. If you opt for this method, keep the shades drawn all the time for the best performance.
Window shutters can affect heating and cooling for the better. Louvered shutters accomplish the same shading effect as Venetian blinds, making them best for reducing heat gain in the summer. Solid shutters provide more effective insulation to reduce heat loss in the winter as well.
In order to open and close interior shutters, the window needs to have a clear wall space on both sides. In addition to energy-efficiency benefits, interior shutters offer protection against the weather and added security.
Exterior shutters add to your home’s aesthetics, but mounting, draining and hinging options require special consideration. It’s easier to install exterior shutters during home construction than as a renovation project.
If you have single-pane windows, you lose a lot of energy as heat transfers easily through the glass. Storm panels provide an affordable upgrade capable of reducing heat loss in the winter by up to 50 percent. Both interior and exterior versions are available. Plan to install the storm panels in the fall and remove them in the spring.
Window screens diffuse some solar radiation, which is effective for reducing heat gain in the summer. Mount mesh screens to the exterior window frame so it covers the entire window. You get the greatest benefit from mesh screens by installing them on east- and west-facing windows where the sun shines directly in during the early morning and later afternoon hours.
Remember, window treatments aren’t effective at reducing air leakage around windows. You need to add caulk and weatherstripping to seal in conditioned air.
For help finding a contractor in your part of the Southeast United States, contact AirConditioningSouthEast.com.