A Look at Window Efficiency Ratings

Window replacement needs to be done periodically as part of your home improvement. Old and damaged windows have to be replaced as soon as possible, as they lose much of their insulation functions which can increase your energy consumption. Likewise, window replacements are a quick and easy way to give your home a makeover and improve its curb appeal.

Replacing a window has to be done with care to give you good value for your money. One of the things you need to watch out for is a window's energy effectiveness. Window replacements come with labels that identify its energy and performance ratings. Two of the most significant ratings are described in detail below.

• U-factor: this measures the rate a window conducts non-solar heat. Some window U-factor ratings may represent only that of the glass or the glazing, but a National Fenestration Rating Council (NFRC) rating covers the performance of the entire window, including the frame. A lower U-factor rating indicates better energy effectiveness

• Solar Heat Gain Coefficient (SHGC): this rates the ability of a window to admit or block solar radiation. A window with a high SHGC is capable of collecting more heat from the sun during the winter, while a window with a low SHGC will block more heat from the sun during the summer. The climate in your area and the location of the window in your home can help determine the SHGC rating that is appropriate for your needs.