Ruud PROG40-34U RH EC1

This site calculated the 188 therms figure; the registry does not list it. The calculation uses 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. This model's UEF is 0.59, from the DOE Compliance Certification Database (CCD), retrieved 2026-09-19. The figure assumes the test's daily draw and nothing else. A household that uses more or less hot water than that draw will use a different amount of gas. The registry data does not show how large that difference would be, so it is not available here. The full method is described in how the annual cost is calculated.

The class is the 288 models registered as a gas tank at the medium draw pattern. Within it, this model ranks 186th from the lowest in energy use. That puts it in the second-highest quarter of its class for energy use. The medium pattern stands for a typical three- or four-person household. The 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. The 188 therms figure applies to a household whose daily use matches the medium pattern. To compare other models in the same class, use find a same-class replacement by model number.

The 188 therms figure does not apply to a household whose busiest hour needs more than the 71-gallon first hour rating. This page has no measured figure for that case, so gas use at a higher draw is unknown here. This text also does not state the running cost. The cost depends on your state's average residential gas price, so the page calculates it from your ZIP. The cost calculator on your own ZIP applies that rate to the 188 therms figure for the medium pattern. The installed-cost range appears in a separate block with its source and date. It is a modeled range, not a quote.