Ruud PROG48-48U RH EC1

This site computed the 264 therms figure; the registry does not publish it. The calculation uses the model's UEF, the ratio of hot water delivered to energy used, and the DOE test's daily hot-water draw for the high draw pattern. The registry lists this model's UEF as 0.64, from DOE CCD data retrieved 2026-09-19. The fuel is natural gas, so the yearly figure is given in therms. The figure applies only at the federal test's daily draw. It is not a measured reading from any home. The method behind the annual cost figure shows each step of the calculation, including where the daily draw comes from.

The high draw pattern represents a larger household, or one where showers and laundry overlap. This model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 88 gallons. The model's rated volume is 46 gallons. Among the 414 gas tank models at this pattern, it ranks 236th lowest in energy use. That puts it in the second-highest quarter of its class for energy use, with a gap of 4 therms a year above the class median. To check other registered models in the same class, use the same-class replacement search by model number.

This page does not state a running cost because it depends on your state's average residential gas price. The page works it out from your ZIP code, starting from the 264 therms yearly figure. The cost calculator for your own ZIP shows that result at your rate. This figure does not describe a household that uses less hot water than the high draw pattern assumes. This page has no energy figure for this model at any other draw pattern, so its use under lighter demand is unknown. The installed price range has its own block on the page. It is a modeled range with its source and date, not a quote.