A. O. Smith HPACO-45 1**+AXST-80 1**

It holds 73 gallons in the test, 7 gallons less than its 80-gallon sold size. Over one hour from a full tank, it gave 95 gallons in the test (its first-hour rating). That is 22 gallons more than its tank holds, since it reheats during the hour. Among 481 heat pump models, 17 have a higher first-hour rating. Among heat pump models, the median first-hour rating is 72 gallons.

Under this basic model, 4 model numbers are ENERGY STAR certified. In the test, it gives 3.80 units of hot water energy per unit it uses (its UEF). It moves heat from the air rather than making it, so its UEF passes 1. Its test ran at the high level of daily hot water use. Its UEF is lower than that of 129 of the 237 heat pump models with its draw pattern. On its draw pattern, the median heat pump UEF is 3.88. Its recovery efficiency is 423%, because it takes heat from the air as it reheats water.

A tag or quote may show any of its 4 model numbers. All of its test figures are shared by 7 other basic models. Each of the 7 other brands lists one of them.

It may qualify for 17 rebate programs. Another 5 programs may accept it if it meets their other terms.