GSW WATER HEATERS HPACO-45 1**+AXST-50LBTTP 1**

It holds 48 gallons in the test, 2 gallons less than its 50-gallon sold size. Over one hour from a full tank, it gave 72 gallons in the test (its first-hour rating). That is 24 gallons more than its tank holds, since it reheats during the hour. Among 481 heat pump models, 240 have a higher first-hour rating. The median heat pump model gives the same amount in its first hour.

It is ENERGY STAR certified under its single model number. For each unit of energy it uses, 3.55 units end up in the hot water (its UEF). A UEF above 1 is possible because it moves heat from the air into the water. The daily hot water use in the test, called its draw pattern, was medium. Its UEF is lower than that of 122 of the 226 heat pump models with its draw pattern. For its type and draw pattern, the UEF runs from 2.59 to 4.23. When it reheats water in the test, the water gains 428% of the energy it uses.

All of its test figures are shared by 7 other basic models. They are listed under 7 other brands, one each. For the full group, see the A. O. Smith HPACO-45 1**+AXST-50LBTTP 1**.

In 17 states, 17 rebate programs may accept it. It may qualify for 5 more if it meets terms its figures do not show.