Knowledge Base

Energy-saving Window Tips

Windows can be one of your home's most attractive features. Unfortunately, they can also account for 10% to 25% of your heating bill. If your home has single-pane windows, consider replacing them with new double-pane windows with high-performance glass (e.g., low-e or spectrally selective). In colder climates such as ours, select windows that are gas filled with low emissivity (low-e) 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 they allow you to buy smaller, less expensive heating and cooling equipment.

If you decide not to replace your windows, the simpler, less costly measures listed here can improve their performance.

Cold-Climate Window Tips

You can use a heavy-duty, clear plastic sheet on a frame or tape clear plastic film to the inside of your window frames during the cold winter months. Remember, the plastic must be sealed tightly to the frame to help reduce infiltration.
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 let in the winter sun.
Install exterior or interior storm windows; storm windows can reduce heat loss through the windows by 25% to 50%. Storm windows should have weather stripping at all movable 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.

Shopping Tips for Windows

Look for the ENERGY STAR label.
Check with local utilities to see what rebates or other financial incentives are available for window replacement.
High-performance windows have at least two panes of glass and a low-e (low emissivity) coating.
Remember, the lower the U-factor, the better the insulation. For Alaska's cool climate, focus on finding a low U-factor.
Look for whole-unit U-factors and SHGCs, rather than center-of-glass, or COG, U-factors and SHGCs. Whole-unit numbers more accurately reflect the energy performance of the entire product.
Have your windows installed by trained professionals. Be sure they're installed according to manufacturer's instructions; otherwise, your warranty may be void.

Replacing old windows is not usually the best way to increase your home's efficiency, even if they're single paned. You're likely to gain much more value by sealing air leaks, installing Energy Star rated heating systems, and making sure your home is properly insulated. Read more.