Rheem XG40S12HE38U0

This site calculated the 191 therms figure; the registry does not publish it. The calculation combines the registry's UEF, the ratio of hot water delivered to energy used, with the daily hot-water draw that the DOE test sets for the medium draw pattern. This model's UEF is 0.58. The inputs come from DOE's CCD registry and were retrieved on 2026-09-19. A household that uses more or less hot water than the test assumes will use a different amount of gas than 191 therms. The registry does not show how large that difference would be. The steps behind the annual energy and cost figures are set out separately.

The tank has a rated volume of 39 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 69 gallons. A first hour rating in this range puts the model in the medium draw pattern, which stands for a typical household's hot-water use. A household whose busiest hour needs more than 69 gallons would use more than this rating covers. For a household whose peak hour stays under 69 gallons, the figure is enough to cover that hour. The registry gives no data on recovery beyond the first hour, so that detail is not available here.

The comparison group is the 288 models registered as gas tanks at the medium draw pattern. Within that group, this model ranks 231st lowest in energy use, which puts it in the highest quarter of its class. The gap from the median is given above and is not repeated here. The running cost is not stated in this text because it depends on your state's average residential gas price. The cost calculator for your own ZIP works it out from 191 therms. The installed-price block on this page shows a modeled range with its own source and date; it is not a quote. To compare against other units in the same class, use the same-class replacement search by model number.