Window Selection

For an excellent overview of Selecting Energy Efficient Windows in Texas, consult the Efficient Window Collaborative's Texas Factsheet.

Window Selection: Using the NFRC Label to find energy efficient windows

NFRC Label

The National Fenestration Rating Council (NFRC) is an international coalition that administers testing, certification and labeling of windows, skylights and doors. NFRC sets energy test standards and administers ratings by independent labs. The NFRC energy performance label helps builders, retailers and consumers reliably compare one product to another.

The NFRC label contains the following performance data:

• U-factor - how well a window keeps heat inside a building -- lower is better
• Solar heat gain coefficient (SHGC) - windows ability to block warming caused by sunlight -- lower is better
• Visible light transmittance - how much light gets through a window -- higher is better
• Air Leakage - heat loss and gain by infiltration through cracks in the window assembly -- lower is better

The 2 most important values to look for are: U-factor and Solar Heat Gain Coefficient (SHGC).

As a good rule of thumb, use the NFRC label to look for products with an SHGC below 0.40 in the South/Central Zone and well below 0.40 in the Southern Zone. The lower the SHGC, the more cooling savings one can expect in Texas. The U-factor is more important in determining one's heating savings, so look for a U-factor below 0.40 in the South/Central Zone and one below 0.65 in the Southern Zone.

For additional information and windows resources, visit the NFRC's discussion of its Energy performance label and its Certified Products Directory.

For an excellent overview of Selecting Energy Efficient Windows in Texas, consult the Efficient Window Collaborative's Texas Factsheet or try out their Window Selection Tool