RELIANCE WATER HEATERS PETX-40 1**

The 3,531 kWh figure does not come from the registry itself. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used, and the DOE test's daily hot-water draw for the medium pattern. The registry lists a UEF of 0.92 for this model in the DOE CCD, retrieved 2026-09-19. The medium pattern stands for a typical family household with a busy morning. If your household draws more or less hot water than that test draw, your yearly use will differ from 3,531 kWh. How far it differs is not available here, because the page only knows the test condition. The steps behind the figure are set out in how the annual cost is calculated.

Against its class, this model ranks 213th lowest energy use of 426 electric tank models at the medium draw pattern. The class median is 3,531 kWh, so the gap to the median is 0 kWh. The registry also gives a first hour rating, the gallons of hot water available in the first hour from a full tank, of 64 gallons. The rated volume is 37 gallons. A household whose busiest hour stays within 64 gallons falls inside what that rating describes. A household that needs more in that hour falls outside it. A reader looking for energy use below the class median will not find it in this model. To compare models in the same class, use find a same-class replacement by model number.

The running cost is not stated in this text. It is the 3,531 kWh yearly figure multiplied by your own utility's electricity tariff, and tariffs differ by location. The page computes it from your ZIP in the cost calculator on your own ZIP. That result keeps the same condition as the energy figure: the medium draw pattern at the federal test's daily draw. The installed price range appears in its own block, with its source and date. It is a modeled installed-cost range, not a quote. Whether this unit's 3,531 kWh costs more or less to run than another model depends on both units' energy figures at the same rate.