Rheem PROG40-34U RH EC1

The figure of 188 therms a year is computed by this site, not published by 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 medium pattern. For the Rheem PROG40-34U RH EC1, the UEF is 0.59, taken from the DOE CCD as retrieved on 2026-09-19. The annual figure holds only at that test draw. A household that draws a different amount of hot water each day will use a different amount of gas. That amount is not available from the registry data. The steps behind the calculation are set out on the page explaining how the annual cost is calculated.

On DOE's test, the medium draw pattern represents a typical household. This model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 71 gallons. Its rated volume is 38 gallons. A plumber or seller verifying a unit can check those figures against the rating plate. A household that needs more than 71 gallons in its first hour of heavy use needs more than this rating covers. At 188 therms a year, the model's rank of 186th lowest of 288 puts it above the median for its class. To look up other gas tank models at the same draw pattern, use the same-class replacement search by model number.

Running cost is not stated in this text. It depends on the average residential gas price in the reader's state. The page calculates it from the reader's ZIP, using the 188 therms a year at the medium draw pattern. The cost calculator on your own ZIP runs the same calculation for a different location. At any gas price, the 3 therms gap above the class median of 185 therms means higher running cost than the median model. The page does not give the size of that gap in cost. The installed price range appears in its own block, with its source and date. It is a modeled installed-cost range, not a quote.