Glass that insulates like walls. Alpenglass™, powered by Next Generation Heat Mirror® technology, is one of the most advanced insulating glass systems on the market today. Able to achieve center of glass R-values ranging from 6 to 20, Heat Mirror® glass insulates as well as a typical wall. By suspending a Heat Mirror® coated film securely between two sheets of glass, Alpenglass™ offers unprecedented thermal insulation and comfort with its multi-cavity insulating glass solution. With such performance, windows utilizing Heat Mirror® insulating glass can substantially lower your energy bills, as well as protect you, your loved ones, and your cherished belongings from harmful UV rays. Recognized by Popular Science magazine as one of the “Top 100 Inventions of the Millennium,” Heat Mirror® insulating glass has been used around the world in state-of-the-art buildings. From single-family homes to high-profile projects like the Empire State Building, Alpenglass™ powered by Heat Mirror® continues to be the glazing solution that architects, builders and homeowners turn to when wanting exceptional performance.