According to the Energy Information Administration, water heaters can account for 19% to 32% of a homeowner's utility bill. One option to reduce the amount of energy needed for water heating is to install a heat pump water heater. Although they use electricity, they can be two to three times more energy efficient than conventional electric-resistance water heaters. Heat pump water heaters operate on the same principle as the whole-house air source heat pumps, which move heat with electric compressors and pumps. However, instead of heating and cooling homes, they move heat from the surrounding space into the water tank.