stream33 S33-HPWH50

It holds 47 gallons in the test, 3 gallons less than its 50-gallon sold size. Over one hour from a full tank, it gave 69 gallons in the test (its first-hour rating). Its tank holds 47 gallons, so reheating adds 22 gallons during the first hour. Of 481 heat pump models, 263 give more hot water in the first hour. The median heat pump model gives 72 gallons in its first hour.

Its single model number, S33-HPWH50, is ENERGY STAR certified. For each unit of energy it uses, 3.75 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. In the test, daily hot water use was set to medium (its draw pattern). Among 226 heat pump models on its draw pattern, 59 have a higher UEF. For its type and draw pattern, the UEF runs from 2.59 to 4.23. Its recovery efficiency is 430%, because it takes heat from the air as it reheats water.

Its test figures match those of 19 other basic models. In all, 17 other brands list one or more of them. For the full group, see the 1HVAC ACIQ-50G-HP-WH.

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.