Rheem PROP G40-50* RH HE EC3

The 188 therms figure is computed by this site, not taken from the registry. 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. For this model the UEF is 0.9, from DOE CCD data retrieved 2026-09-19. The figure holds only at that test draw. It does not describe a household whose daily hot-water use differs from the test. Against the 414 gas tank models at the high draw pattern, it ranks 1st for lowest energy use. That places it in the lowest quarter of its class. The page on how the annual energy and cost figures are calculated sets out each step.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. The 260 therms class median and the 72 therms gap both apply to that pattern only. 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 40 gallons. A home whose busiest hour needs more than 88 gallons falls outside what this rating covers. A home with lower daily use than the high pattern is also not described by the 188 therms figure. This page does not give an energy figure for this model at a lower draw pattern. To compare other units, use the water heater selector by fuel, space and size.

The running cost is not stated in this text. It depends on the state average residential gas price where the reader lives. The page therefore computes it from your ZIP, and the running cost calculator for your own ZIP applies that rate to 188 therms. An installed price range is not published for this model. Its ratings, including the UEF of 0.9, lie outside the range the cost database's model was fitted on. That range is not extended beyond the fitted data. To check another unit in the same class, a gas tank at the high draw pattern, use the same-class replacement search by model number.