Windows energy efficiency rating

Savings and costs vary based on the material and its construction process. Glass Double-pane dual-pane glass naturally performs better than single-pane glass for energy efficiency, as the space between each pane acts as an additional layer of insulation from the heat or cold. Low-E glass is optimal for conserving energy because it reduces ultraviolet UV and infrared light penetration to limit heat transfer.

How do I know if a window is energy efficient? How do energy efficient windows work? Do energy-efficient windows increase home values? How much money do energy efficient windows save?

Where to Buy. See All Locations. Dealer Website. There are tips for improving the energy-efficiency of windows; while homeowners might see significant savings, they may be able to reduce drafts and increase insulation. Many home stores sell film that can be installed over each window to act as a seal against the weather. These insulation films are easy to apply and are fairly inexpensive. Homeowners also may experience drafts because of other issues.

Old House Online explains that the attic of an older home may be the cause of those cold drafts. In this case, homeowners may need to add more insulation to the attic. If homeowners are unsure why a room is feeling colder during the winter, they may need to do a home energy audit.

Homeowners can download HomeSelfe to help them find energy drains in every room in their home. The app will identify any energy drains and give homeowners more tips on how to cut costs. If the windows are a problem, HomeSelfe will find out.

The app also can help homeowners find any rebates that could help them offset the costs of those new windows! Login Support About Us. Energy Performance Testing, Certification, and Labeling. Heat Gain and Loss. Windows, doors, skylights can gain and lose heat through: Direct conduction and convection heat transfer through the glass or multi-layer glazing and framing Thermal radiation into a house and out of a house from room-temperature objects, such as exterior walls and windows, people, equipment, furniture, and interior walls The solar radiation into a house, which is converted to heat when absorbed by building surfaces Air leakage through and around them.

These properties can be measured and rated according to the following energy performance characteristics: U-factor is the rate at which a window, door, or skylight transmits non-solar heat flow.

For windows, skylights, and glass doors, a U-factor may refer to just the glass or glazing alone. NFRC U-factor ratings, however, represent the entire window performance, including frame and spacer material. The lower the U-factor, the more energy-efficient the window, door, or skylight. The lower the SHGC, the less solar heat it transmits and the greater its shading ability. A product with a high SHGC rating is more effective at collecting solar heat during the winter.

A product with a low SHGC rating is more effective at reducing cooling loads during the summer by blocking heat gain from the sun.