Window Selection

For a highly efficient window that will meet the 2015 IECC in all Texas climate zones, we recommend selecting a window with no more than 0.35 U-Factor and no more than 0.25 Solar Heat Gain Coefficient.

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:

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


Use the NFRC label to look for products with an SHGC below 0.25 and ideally lower. The lower the SHGC, the more cooling savings one can expect in Texas. The U-factor is more important in determining heating savings, so look for a U-factor below 0.35 in all Texas climate zones.

Learn more on our NFRC Labeling System page or visit the NFRC website and Certified Products Directory.

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