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Double- and triple-pane windows make a home or office more comfortable and more energy-efficient. Cut your heat loss in half by choosing these eco-friendly window options.

How to install double pane windows

Double-pane windows (alternatively known as storm or double-glazed, and not to be confused with double-hung windows) have two panes of glass. Together, these layers cut heat loss by 50 percent or more. Take a peek at these options when shopping for new windows:

  1. Glass tinting: Bronze, gray, or high-performance (spectrally selective) tinted glass can reduce solar gain, which is especially helpful during hot summer months. Because these tints have no effect on the U-factor, they aren’t recommended for colder-climate areas.
  2. Gas fills: Take advantage of the two panes of glass on your new windows by filling them with gas, which will further boost their energy efficiency. Argon and krypton are the two most common options, either of which can be used on their own or in combination. Argon is less expensive than krypton, but since krypton has better thermal performance, it is preferred in colder regions.
  3. Low-e films or coatings: If you’re in the process of replacing windows, be sure to look into low-e options to further cut back on energy use.
  4. One, two, or three?: Double-pane windows are definitely more energy efficient than single-pane windows and are good options for most regions. However, if you happen to live in an area that experiences extreme cold, you may want to consider triple-pane windows, which prevent even more heat transfer.
  5. ENERGY STAR options: Windows that are ENERGY STAR rated will often contain many of the features listed above and can save the typical homeowner between $125-450 per year when single-pane windows are replaced with double-pane windows.

Before you buy

Select windows with U-factors suitable to your area: Whether you choose double- or triple-pane windows, be sure to get them with the correct U-factor, which is indicated on a new window's label . In general, a 0.35 is best for colder locales; you can get away with a U-factor of 0.65 in warmer climes. Check out ENERGY STAR’s Climatic Zones map or Efficient Windows Collaborative Window Selection Tool to find out which windows are best for your specific region.

Find it! Double-pane windows

Installing double-pane windows helps you go green because…

  • They cut heat loss, thus reducing heating-related energy consumption and carbon dioxide emissions.

Double-pane windows employ two glass layers with an air space (sometimes gas-filled) between to cut heat flow. The biggest benefit is a lower U-factor, but double- and triple-pane windows can also cut a window’s solar heat gain coefficient (SHGC).[1] Energy-efficient windows, including those that are double- or triple-paned with low-e coatings, can reduce heating costs by 34 percent and cooling costs by 38 percent[2] compared to conventional, single-pane windows.[3] In fact, the average homeowner can cut his or her annual carbon dioxide emissions by 10,000 pounds and save $436 per year by replacing single-pane windows for double-glazed varieties.[4]

Tax breaks and subsidies

In the US, upgrading your home's windows may qualify you for tax incentives at the federal, state, or local levels. For detailed information, see these resources:

Glossary

  • double-hung windows: The two sashes on these windows both slide vertically. On single-hung windows, only the bottom sash slides upward. Both single- and double-hung windows tend to experience more air leakage compared to projecting or hinged windows.[5]
  • solar heat gain coefficient (SHGC): Solar heat can be admitted through a door or window either by direct transmission or through absorption. SHGC measures the fraction of heat caused by sunlight on a scale between zero and one, smaller numbers indicating lower levels of heat transfer.
  • U-factor: The inverse of the R-factor (a measure of a material's insulating ability; higher numbers indicate better performance), U-factor also measures the rate of heat gain and loss. However, the higher the U-factor number (values range from 0.20 and 1.20), the less the product is able to resist heat flow (i.e., the worse its insulating ability).

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