US Energy Guide label on a household water heater. The US Federal Trade Commission's Appliance Labeling Rule requires manufacturers to put yellow-and-black Energy Guide labels on most major home appliances such as refrigerators, dishwashers, clothes washers, water heaters and air conditioners. These labels contain information about the energy efficiency of a particular appliance. The efficiency ratings are based on standard test procedures developed by the US Department of Energy. Shown here is the Energy Guide label on a natural gas water heater manufactured by Bradford White. Photo Sept 2007.