Energy Efficient Windows – Understanding Performance Ratings
Posted By Houston Decorator on September 21, 2010
If you are looking for energy efficient replacement windows for your home, it’s important to understand how window efficiency is rated.
Window performance is measured according to a rating system developed by the National Fenestration Rating Council (NFRC). There are two important ratings that the NFRC uses to measure a window’s energy performance: U-Factor and Solar Heat Gain Coefficient. Many window manufacturers will also refer to a window’s R-Value, which is also used to assess the energy efficiency of many other building materials.
U-Factor
U-Factor represents the amount of heat that escapes through a window. The lower the U-Value, the more energy efficient the window is, and the better its insulation capabilities. A low U-Factor keeps heating costs low, because the heat is retained inside the home. The U-Factor listed on an NFRC label refers to the insulation performance of the window as a whole, including the glazing and frame. This is usually higher than the center-of-glass U-Factor, which rates the performance of the glass on its own, without the frame.
Solar Heat Gain Coefficient
The solar heat gain coefficient (SHGC) measures how much solar heat is transmitted inward through the window. The lower the SHGC, the less heat from sunlight the window lets into the house. Windows with a low SHGC will help keep air condition bills down during warm weather.
R-Value
R-Value is essentially the opposite of the U-Factor. A window’s R-Value measures its resistance to heat flow. A higher R-Value indicates a more energy efficient product with better insulation properties.
Greg Cassidy is the General Manager of Maintenance Free Windows, metro-Atlanta and north Georgia’s best value for vinyl replacement windows. Maintenance Free Windows offers a variety of affordable and 100% guaranteed top quality products. All products and materials that go into each installation are of the most premium grades available. Because Maintenance Free Windows always pays close attention to the details, the customers are always assured of the finest home improvement projects possible.
For more information about Atlanta Windows, visit: http://www.MaintenanceFree.com/
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