Rheem PROG40-38N RH62

The 191 therms figure is not a registry field. This site calculated it from the registry's UEF, the ratio of hot water delivered to energy used, and from the daily hot-water draw in the DOE test for the medium draw pattern. This model's UEF is 0.58, taken from DOE CCD data retrieved 2026-09-19. The figure applies only at that test draw. A household that uses more or less hot water will use a different amount of gas. The comparison class is the 288 models registered as a gas tank at the medium draw pattern. At the test draw, this model uses 6 therms a year more than that group's median of 185 therms. The steps are explained on the page on how the annual cost is calculated.

In the DOE test, the medium draw pattern stands for the daily hot-water use of a typical household. The model's data lists a rated volume of 38 gallons. It also lists a first hour rating, the gallons of hot water available in the first hour from a full tank, of 64 gallons. These two figures describe supply, not energy use. A plumber or seller checking a listing can compare them, and the UEF of 0.58, with the unit's label. A reader may want a gas tank at the same draw pattern that uses less energy than the 185 therms median. That reader can compare models with the same-class replacement search by model number. Its results are limited to models in the same comparability class.

The text on this page does not state a running cost. What 191 therms of natural gas costs depends on your state's average residential gas price, so the page calculates it from your ZIP. The same applies to the 6 therms gap from the class median. What that gap costs follows your rate, so no fixed figure is given here. To see the result on your own rate, use the cost calculator on your own ZIP. The installed price range on this page appears in its own block with its source and date. It is a modeled installed-cost range, not a quote. The registry data does not include your household's actual gas use or bill, so neither is stated here.