The new integrated air-source HP-50 Heat Pump Water Heater from Rheem Water Heating offers an industry-leading Energy Factor of 2.0. This unit has a storage capacity of 50 gal. and meets the qualifications for an Energy Star listing. Measuring only 21 in. in diameter and 75.5 in. tall, the new Rheem Heat Pump Water Heater offers a slimmer, more portable profile that makes installation in spaces with restricted access much easier.