What is

Energy Star® is a program run by the U.S. Department of Energy and the EPA. For windows and doors, the Energy Star® label can be affixed only to windows and doors that meet specific U-value and shading coefficient ratings for one or more regions of the country. These ratings are achieved through independent testing done to NFRC (National Fenestration Ratings Council) standards. The ratings vary due to the the window or door style, the type of glass and the overall product design.