Saving With Windows…
Energy Saving Window Options
Windows can be one of a home's most attractive features. Windows provide views, daylighting, ventilation and solar heating in the winter. Unfortunately, they can also account for 10 percent to 25 percent of a heating bill. During the summer, sunlight streaming through windows can make an air conditioner work two to three times harder.
If your home has single-pane windows, as almost half of U.S. homes do, consider replacing them. New double-pane windows with high-performance glass also called low-e or spectrally selective are available on the market. In colder climates, select windows that are gas filled with low-emissivity coatings on the glass to reduce heat loss.
If you are building a new home, you can offset some of the cost of installing more efficient windows because doing so allows you to buy smaller, less expensive heating and cooling equipment.
If you decide not to replace your windows, the simpler, less costly measures listed below can improve the performance of your windows.
Cold-Climate Window Tips
Double-pane windows with low-e coating on the glass reflect heat back into the room during the winter months.
- Install exterior or interior storm windows; storm windows can reduce your heat loss through the windows by 25 percent to 50 percent. Storm windows should have weatherstripping at all moveable joints, be made of strong durable materials and have interlocking or overlapping joints. Low-e storm windows save even more energy.
- Repair and weatherize your current storm windows, if necessary.
- Install tight-fitting, insulating window shades on windows that feel drafty after weatherizing.
- Close your curtains and shades at night; open them during the day.
- Keep windows on the south side of your house clean to maximize solar gain.
Buying New Windows
New windows are long-term investments that have a large impact on a home's energy systems. Today, there are many new window technologies available that are worth considering, especially those with the ENERGY STAR® label. Glazing materials now come with a variety of selective coatings and other features. Frames are available in aluminum, wood, vinyl, fiber glass or combinations of these materials. Each type of glazing material and frame has advantages and disadvantages.
Source: Tips for Energy Savers, U.S. Department of Energy
When you're shopping for new windows, look for the National Fenestration Rating Council (NFRC) label. The label means the window's performance has been certified.
- Remember, the lower the U-value, the better the insulation. In colder climates, a U-value of 0.35 or below is recommended. These windows have at least double glazing and low-e coating.
- Select windows with air leakage ratings of 0.3 cubic feet per minute or less.
- In temperate climates with both heating and cooling seasons, select windows with both low U-values and low solar heat gain coefficiency to maximize energy benefits.
- Look for the ENERGY STAR® and EnergyGuide label.