The most efficient General Electric water heaters in production in 2015 are models in the GEH and BEH series. These models have an energy factor rating of 3.1 and are certified as ENERGY STAR water heaters by the U.S. Department of Energy.
GEH and BEH water heaters are considered high-efficiency electric storage water heaters, also known as electric heat pump water heaters. These models operate by transferring heat from the air surrounding the tank to the water inside, a more efficient process than heating the water directly. However, these water heaters do switch to conventional electric heating during periods of high demand.