Either site or source energy can be an appropriate metric when comparing or analyzing energy use of different facilities. The U.S Energy Information Administration, for example, uses primary (source) energy for its energy overviews but site energy for its Commercial Building Energy Consumption Survey and Residential Building Energy Consumption Survey. The US Environmental Protection Agency 's Energy STAR program recommends using source energy, and the US Department of Energy uses site energy in its definition of a zero net energy building.