The U.S. Environmental Protection Agency has announced that 25 percent of all single-family homes built in the United States in 2010 earned EPA’s Energy Star certification. This is up from 21 percent in 2009, according to Energy Boom. 
Energy Star is a joint EPA, U.S. Department of Energy (DOE) program that helps consumers save money and protect the environment by using less energy. This means energy-efficient products, like refrigerators and dishwashers, and homes built to stringent energy-efficient standards that guarantee fewer kilowatt-hours of electricity used to heat and cool, and therefore lower utility bills.
New homes can earn the Energy Star label by meeting certain specific energy-efficiency mandates established by the EPA. These include: