Rheem PROG40-38N RH62

It holds 38 gallons in the test, 2 gallons less than its 40-gallon sold size. Over one hour from a full tank, it gave 64 gallons in the test (its first-hour rating). Reheating lets it give 26 gallons beyond the 38 gallons in its tank. Among 763 gas storage models, 629 have a higher first-hour rating. The median gas storage model gives 78 gallons in the first hour of the test.

On Oct 26, 2026, this heater was not listed as ENERGY STAR certified. In tests, 58% of the energy it uses ends up as hot water (UEF 0.58). Its test ran at the medium level of daily hot water use. Of 288 gas storage models with the same draw pattern, 230 have a higher UEF. For its type and draw pattern, the UEF runs from 0.57 to 0.75. The water took in 74% of the energy used to reheat it (its recovery efficiency).

All 4 of its model numbers carry the same certified figures. There are 8 more basic models with the same test figures. Each of them is listed under a different brand. You can find the whole group on the page for the A. O. Smith GCRL-40 2**.