Projected to reduce water-heating expenses by up to 62 percent, this unit saves as much as $320 a year. In hybrid mode, the tank uses the heat pump, but it has a standard mode that uses the electric element instead. The 50-gallon unit has an energy factor of 2.35. Cost: $1,599.GE Appliances & Lighting. 800-447-1700. www.ge.com.
With an energy factor of 2.3, this unit is more than twice as efficient as a standard tank. It operates like an air conditioner in reverse, so it pulls heat from the surrounding air and transfers it to the tank. It costs just $203 a year to operate as op-posed to $575 for standard tanks. Cost: $1,900 to $2,000.A. O Smith Water Products Co.866- 362-9898.www.aosmith.com.
Designed for smaller homes with lower demand for hot water, the HP-40 water heater is a 40-gallon unit with an energy factor of 2.0, or twice the efficiency of a standard electric unit. It measures 21 inches in diameter and 65.5 inches tall. Cost: $1,400.Rheem Manufacturing Co.800-621-5622.www.rheem.com.
With an energy factor of 2.0, this unit has three modes: energy saver, which uses the heat pump; high demand, which uses a combination of heat pump and electric heating; and electric element only. It measures 75 ½ inches tall. Cost: $1,500.Ruud Water Heating. 800-432-8373.www.ruud.com.