National Fenestration Rating Council Certification

Overview\n\nThe NFRC rating system provides consistent, reliable energy performance ratings that appear on all certified products. Ratings include U-Factor, Solar Heat Gain Coefficient (SHGC), and Visible Transmittance.\n\n## Key Ratings\n\n- U-Factor — measures heat transfer; lower is better\n- SHGC — measures solar heat gain; lower blocks more heat\n- VT — measures visible light transmission\n\n## Code Requirements\n\nNFRC ratings are referenced by ENERGY STAR, California Title 24, and most major building energy codes.