Ruud PROG40-36P RH67 PV

The 163 therms figure is computed by this site, not published by the registry. It uses the registry's UEF, the ratio of hot water delivered to energy used, which is 0.68 for this model. It also uses the DOE test's daily hot-water draw for the medium pattern. Registry values come from the DOE CCD, retrieved 2026-09-19. Among the 288 gas tank models at the medium draw pattern, this one ranks 5th lowest in energy use. That places it in the lowest quarter of its class. The figure holds only at the test's draw and does not measure any particular household's use.

The medium draw pattern is the DOE test's pattern for typical household use, the level at which this model's 163 therms was computed. This model holds a rated volume of 38 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 71 gallons. A household whose busiest hour stays within 71 gallons is inside what this rating describes. A household that draws more in its busiest hour falls outside what the rating describes. Readers matching an existing unit can find a same-class replacement by model number among the 288 models in this class. Readers comparing other sizes or fuels can use the selector by fuel, space and size.

Running cost is not stated in this text, because it depends on your state's average residential gas price. The page computes it from your ZIP by applying that price to the 163 therms yearly figure. At any gas price, this model costs less a year than the 185 therms class median at the test draw. How much less depends on your rate and is not available here. Use the cost calculator on your own ZIP to see the figure for your state. The page's method for calculating the annual cost explains the inputs. The modeled installed-cost range appears in its own block, with its source and date, and is not a quote.