Energy Efficiency Remodeling Tips: Brush Up Your D.I.Y. Vocabulary
Energy Efficiency Terms that Every Homeowner Should Know

KLAMATH FALLS, Ore. April 03, 2007 — When it comes to shopping for energy efficient windows and doors, most homeowners don’t know their “U-Factors” from their elbows. But there are important industry terms that homeowners need to understand in order to select the right products for their needs, according to the experts at JELD-WEN Windows & Doors.

Window and door efficiency is measured in a number of ways, so it’s important to base choices on industry certifications, not a manufacturer’s advertising claims. The National Fenestration Rating Council (NFRC) conducts tests for energy efficiency based on the entire product, not just the glass.

Efficiency ratings are based on these important factors:

U-Factor:  This is the amount of heat flowing through a product.  The lower the number, the more energy efficient the product is.

• Solar Heat Gain Coefficient (SHGC):  This indicates the ability to block heat generated by sunlight.  The greater the blockage, the lower the SHGC.
• Visible Light Transmission:  This is the percentage of sunlight that penetrates a window or door. A higher number means more light enters through the glass.
• Low-E Glass: Low-E, or low emissivity, refers to a transparent metallic coating applied to one surface of insulated glass. In the winter, Low-E reflects some of the interior heat back into the home. In summer, Low-E glass reduces the amount of the sun’s heat from entering the home, lowering cooling needs. Manufacturers have improved the energy-saving qualities of Low-E glass, with products such as Low-E366, which offers greater protection from solar heat gain.

The easiest way to identify the most energy efficient products on the market is to look for the ENERGY STAR label on products qualified by the Environmental Protection Agency.

In order to be ENERGY STAR qualified, a company must be NFRC certified. NFRC certification is conducted by a third-party organization that uses industry accepted standards for evaluating and certifying energy performance. 
 
When it comes to windows and doors, the ENERGY STAR program also takes into account those products most suitable for particular regions and climates.  Look for windows and doors with the label that shows they meet ENERGY STAR qualifications suitable for your region.