Welcome to ThermoLite! Since 1974 ThermoLite has been providing both residential and commercial building professionals with state of the art window and glass products. Plans are taken from drawing board to finished piece in our expansive northeastern Pennsylvania manufacturing facility. Keeping all production in-house allows us to maintain a high standard of quality while offering you virtually limitless possibilities on every project. We are manufacturers of all types of insulated windows, including Commercial, Residential & Specialty.