A. O. SMITH G6N-UT4040NVR 5**

The figure of 264 therms is not a registry entry. This site computed it from the registry's UEF of 0.64 and the daily hot-water draw the DOE test assigns to the high draw pattern. UEF, the ratio of hot water delivered to energy used, comes from the DOE CCD, retrieved 2026-09-19. The result applies only at that test draw and only to natural gas. Real use in a home differs with how much hot water the household draws, and this page does not estimate by how much. The calculation is set out in how the annual cost is calculated.

Among the 414 models registered as a gas tank at the high draw pattern, this unit ranks 236th lowest energy use of 414. Its use sits 4 therms above the class median of 260 therms. 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, with a rated volume of 38 gallons. The data does not say whether that covers your own busiest hour. If lowest energy use within the class is your priority, a rank of 236th places this unit below many of its peers. The water heater selector by fuel, space and size filters by other needs.

The running cost is not written here because it depends on the gas price you pay. The site uses the state average residential gas price, and the cost calculator for your own ZIP applies it to 264 therms, the figure at the high draw pattern. The same price applied to the 4 therms gap from the class median of 260 therms gives the yearly cost difference from a median model. A household that draws more or less hot water than the test draw will land above or below the result. The installed price range appears in its own block on this page, with its source and date, as a modeled range and not a quote. Its figures are not repeated here.