How to Read NFRC Window Energy Efficiency Labels

Whenever you’re buying windows in Houston TX, you’re going to encounter a National Fenestration Rating Council (NFRC) label. This label rates the reliability and energy performance of the product it’s attached on. Furthermore, it shows you different kinds of ratings that describe the energy efficiency features of a particular product. NFRC labels are actually a prerequisite for a product to be ENERGY STAR certified.


This is one of the most important ratings that the NFRC provides. The U-factor tells you how well a window is at preventing heat from escaping a home or an establishment. U-factor ratings are usually between 0.15 and 0.20. The lower the U-factor rating of a product is, the better it is at preventing heat from escaping.


This stands for solar heat gain coefficient, and it’s also one of the more important ratings in an NFRC label. This measures the amount of heat that a product can block. This rating is usually between 0 and 1. The lower the SHGC rating, the better the product is at blocking solar heat gain.


Visible transmittance, also known as VT, is one of the additional energy efficiency ratings that the NFRC gives. This rating tells you how much light passes through a product. This is also expressed between 0 and 1. Unlike other measurements, the bigger or higher the VT rating of a product is, the more light it allows to pass through.

Air Leakage

Air leakage is another energy efficiency rating. It measures the amount of outside air that is able to seep into the interior through the product.

NFRC energy efficiency ratings are important to understand to ensure that the product you’ll purchase offers superior performance. For window replacement in Houston TX that exceeds ENERGY STAR qualifications, choose Renewal by Andersen®.

For more information on these ratings as well as our products and services, call Renewal by Andersen of Houston today.