The HERS Index Score is the one number that tells you how energy efficient a home really is. Like a MPG label for homes, it lets you comparison shop for homes based upon energy performance, the same way you can for appliances and cars. The HERS Index is now the national standard for measuring a home’s energy efficiency that is recognized by the Department of Energy (DOE), the Environmental Protection Agency (EPA), and the U.S. mortgage industry. The HERS Index Score is also a requirement for a home to become Energy Star Certified. So if you want to know more about a home’s energy efficiency before you purchase it, ask for the HERS Index Score!