Window Efficiency
You can save money on your energy Understanding how windows work can help you control your energy costs. Windows are great for views, ventilation, and daylight, but can be a source of heat loss in the winter and heat gain in the summer. Windows are responsible for about 10-25% of your home's winter heating bill. Unwanted solar heat gain through windows in the summer can make your air conditioner work two to three times harder. (source: EREN)
Whether you are building a new house or replacing windows, the following recommendations will help you choose windows that are just right:
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Look for the NFRC label as your guide to their energy performance. The U-factor measures the window's ability to insulate - the lower the U-factor, the more efficient the window.
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Select windows with low air leakage ratings - between. 0.01 and 0.06 cfm/ft.
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To maximize energy performance, choose windows with large unbroken glazing areas instead of multi-pane windows. Applied grills that simulate multi-pane windows are fine; they do not reduce energy efficiency.
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Choose windows with good warranties against the loss of the air seal. If the glazing seal is lost, low conductivity gas between the layers of glass will immediately be lost, and fogging occur.
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To ensure that your new windows perform as well as they should, hire a skilled contractor to install them.
For additional information on energy-efficient residential windows, check out these links to related sites:
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Efficient Windows - This web site provides unbiased information on the benefits of energy-efficient windows, descriptions of how they work, and recommendations for their selection and use.
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Energy Star - ENERGY STAR labeled windows can keep your house comfortable and help save money on utility bills through superior designs that require less money and less energy.
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National Fenestration Rating Council - NFRC is a nonprofit organization created by the window, door and skylight industry to develop a window energy rating system based on whole product performance.
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Consumer Energy Information: EREC Fact Sheets - This site provides detailed information on identifying ways to make your windows more efficient.
Source: Energystar.gov
