Ruud PROG40S-40N RH62

It holds 39 gallons in the test, 1 gallon less than its 40-gallon sold size. Over one hour from a full tank, it gave 66 gallons in the test (its first-hour rating). Its tank holds 39 gallons, so reheating adds 27 gallons during the first hour. Among 763 gas storage models, 585 have a higher first-hour rating. The median gas storage model gives 78 gallons in its first hour.

On Oct 26, 2026, this heater was not listed as ENERGY STAR certified. In the test, 42% of its energy does not reach the hot water (UEF 0.58). Its test simulated a day of medium hot water use (its draw pattern). Among 288 gas storage models on its draw pattern, 230 have a higher UEF. For its type and draw pattern, the UEF runs from 0.57 to 0.75. Of the energy spent to reheat water, 75% goes into it (its recovery efficiency).

It is sold under 5 model numbers in all. All of its test figures are shared by 3 other basic models. Those basic models are sold with Friedrich, Rheem, and Richmond as their brand names. You can find the whole group on the page for the Rheem PROG40S-40N RH62.