Energy Performance and Technical Info
Windows are complex creatures with many component parts. They all contribute to the quality, durability, beauty and efficiency of the finished product.
Windows today are tested by the NFRC. The National Fenestration Ratings Council is a nonprofit, public/private organization created by the window, door and skylight industry. It is composed of manufacturers, suppliers, builders, architects and designers, specifies, code officials, utilities, and government agencies. The NFRC has developed a window energy rating system based on whole product performance.