A. O. SMITH G9-UT4040NVR 5**

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.64 for this model. This site multiplied that UEF by the DOE test's daily hot-water draw for the high draw pattern to reach 264 therms of natural gas a year. The registry does not publish that annual figure, and the method used to calculate the annual figure is documented separately. The source is the DOE CCD, retrieved 2026-09-19. Against the class median of 260 therms, this model sits 4 therms above. Its rank is 236th lowest energy use of 414, which puts it in the second-highest quarter of its class for energy use. The figure applies at the test's draw and is not a measurement of any one household.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The first hour rating, the gallons of hot water available in the first hour from a full tank, is 83 gallons for this model, and the rated volume is 38 gallons. A reader can compare those two values with their own busiest hour of hot-water use. The figure of 264 therms holds only for the high draw pattern; a household that draws less would use a different amount, which this page does not calculate. A reader who wants the lowest gas use in the class may look further, since this model ranks 236th lowest of 414. The selector by fuel, space and size or a same-class replacement by model number covers other options.

The running cost is not stated here because it depends on the state average residential gas price, which differs by reader. To get a figure, use the cost calculator on your own ZIP, which applies your state's rate to the 264 therms shown above. The result carries the same condition as the energy figure: the high draw pattern at the federal test's daily hot-water draw. It will differ from an actual bill if real use differs from the test. The modeled installed-cost range appears in its own block on this page, with its source and date. It is a modeled range, not a quote, and it is not repeated in this text.