Rheem PROG48-48U RH EC1

The 264 therms figure comes from this site's calculation. The registry does not publish it. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily hot-water draw for the high draw pattern. This model's UEF is 0.64, from the DOE CCD as retrieved on 2026-09-19. The total holds only at that test draw. A home that uses more or less hot water will have a different total. Among the 414 models registered as a gas tank at the high draw pattern, this one ranks 236th for lowest energy use. That places it in the second-highest quarter of its class for energy use. The page on how the annual figure is calculated sets out each step.

The high draw pattern describes a larger household, or one where showers and laundry overlap. This model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 88 gallons. Its rated volume is 46 gallons. The 264 therms total applies to a home close to that test usage. A smaller household that draws less hot water does not match the test condition, so the figure would not describe its use. This page does not have figures for this model at other draw patterns. For a model sized to a different household, the selector by fuel, space and size filters the registry.

The running cost is not given in this text. It depends on your state's average residential gas price. The page applies that price to the 264 therms total once you enter your ZIP. The 4 therms gap to the class median, noted above, carries into cost at your own rate per therm. The installed price range appears in its own block, with its source and date. It is a modeled range, not a quote. To run the figure on your rate, use the cost calculator for your ZIP. To compare units in the same class, you can find a same-class replacement by model number.