State HPTA-40 2**

It holds 36 gallons in the test, 4 gallons less than its 40-gallon sold size. Starting full, it gives 55 gallons of hot water in its first hour of use. Reheating lets it give 19 gallons beyond the 36 gallons in its tank. In the first hour, 418 of the 481 heat pump models give more hot water. The median heat pump model gives 72 gallons in its first hour.

Under this basic model, 2 model numbers are ENERGY STAR certified. In the test, it gives 3.60 units of hot water energy per unit it uses (its UEF). Pulling heat from the air lets its UEF pass 1. In the test, daily hot water use was set to medium (its draw pattern). Of 226 heat pump models with the same draw pattern, 115 have a higher UEF. A UEF of 3.68 is the median for its type and draw pattern. While it reheats, the water gains 426% of the energy it uses (its recovery efficiency).

It is sold as CSHP-40 2** and HPAX-40-DHPT 2**. There are 4 more basic models with the same test figures. Each of the 4 other brands lists one of them. You can find the whole group on the page for the A. O. Smith HPTA-40 2**.

It may qualify for 21 rebate programs in 20 states. It may qualify for 7 more if it meets terms its figures do not show.