RELIANCE WATER HEATERS GUC 40 4**

This site computed the 264 therms figure. The registry does not publish 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 high draw pattern. This model's UEF is 0.64, taken from DOE CCD data retrieved 2026-09-19. So the figure describes the federal test's usage, not the water a particular home draws. A home that uses less hot water than the test assumes will use less gas, and a home that uses more will use more gas. The size of that difference for any one home is not available, because actual household usage is not in the data. The steps are set out on the page explaining how the annual energy and running cost are calculated.

The high draw pattern stands for a larger household, or a household 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 83 gallons, from a rated volume of 38 gallons. It suits a home whose peak-hour demand fits within that 83-gallon rating. It ranks 236th for lowest energy use among the 414 gas tank models at this pattern. For a reader who wants lower gas use at the same test draw, the models ranked ahead of it use less. The same-class replacement search by model number lists models from this class. The data does not say how any model performs in a specific home.

The running cost is not given in this text. It depends on your state's average residential natural gas price, applied to 264 therms a year. The page works it out from your ZIP code in the water heater running cost calculator for your own ZIP. Because this model's energy use is 4 therms above the 260 therms class median, it will cost a little more to run than the median model at any single gas rate. The size of that cost gap depends on your rate, so it is not stated here. The installed price range appears in its own block, with its source and date. It is a modeled range, not a quote. Future gas prices are not in the data.