All major standards and programs for window energy efficiency — including building energy codes, tax credits and utility incentives, ENERGY STAR, and others — base their criteria on certified ratings by the National Fenestration Rating Council (NFRC). To ensure that their products are recognized, manufacturers must therefore participate in the NFRC certification and labeling program.

What is the NFRC?
The National Fenestration Rating Council (NFRC) is a nonprofit, public/private organization created by the window, door, and skylight industry. It is composed of manufacturers, suppliers, code officials, researchers, and government agencies. The NFRC has developed a fenestration energy rating system based on certified whole product performance.

The NFRC Label
The NFRC label provides the only reliable way to determine energy properties and compare the energy-efficiency of fenestration products. NFRC labels show certified ratings for U-factor, Solar Heat Gain Coefficient (SHGC), and Visible Light Transmittance (VT), and optionally for Air Leakage (AL) and Condensation Resistance (CR).