Ruud RHE40S

The 204 therms figure was calculated by this site. The registry does not publish it. It pairs the registry's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily draw. For the RHE40S, the UEF is 0.83, taken from DOE CCD data retrieved 2026-09-19. At the high draw pattern, the model ranks 25th lowest in energy use of 414 gas tank models. That places it in the lowest quarter of its class for energy use. A home that draws more or less hot water than the test assumes will use a different amount of gas. This page does not know that amount for any single home. The method behind the figure is explained on the page about how the annual cost is calculated.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The RHE40S has a rated volume of 37 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 87 gallons. A home that needs more than 87 gallons in its busiest hour needs more than this rating covers. The 204 therms figure applies only to natural gas at the high draw. It does not describe how much gas a smaller household would use. To compare units that differ in fuel, space or size, use the selector by fuel, space and size. To check other gas tank models in the same class, find a same-class replacement by model number.

The running cost is not stated in this text. It depends on your state's average residential gas price, so the page calculates it from your ZIP. That price is applied to the 204 therms used at the high draw pattern. The 56 therms gap to the class median is also an amount of gas, and its cost depends on the same rate. You can calculate the figure yourself with the cost calculator for your own ZIP. An installed price range is not published for this model. Its ratings lie outside the range that the cost database's model was fitted on, and the range is not extended past it.