NFRC and codes
National Fenestration Rating Council (NFRC) is a non-profit, public/private organization created by the window, door and skylight industry. It is comprised of manufacturers, suppliers, builders, architects and designers, specifiers, code officials, utilities and government agencies. NFRC provides consistent ratings on window, door and skylight products.
NFRC's primary goal is to provide accurate information to measure and compare the energy performance of window, door, or skylight products.
GPL, GGL, GDL products are manufactured in Europe and are not NFRC certified.