A. O. SMITH ENT-55 1**

The 3,493 kWh is a computed value, not a metered one. This site calculated it from the registry's UEF, the ratio of hot water delivered to energy used, and the test's daily hot-water draw. The registry lists a UEF of 0.93 for this model. The condition is the medium draw pattern, so a household that uses more or less hot water will see a different figure. The energy data comes from DOE CCD, retrieved 2026-09-19. The registry itself does not publish this annual figure. The steps are set out on the methodology page.

The class is the 426 models registered as an electric tank at the medium draw pattern. Its median is 3,531 kWh, and this model sits 38 kWh below it. That places it in the second-lowest quarter of its class for energy use. The data does not compare it with other fuels or other draw patterns. Its rated volume is 55 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 72 gallons. These values match a typical three- or four-person household at the medium draw pattern. A household with a different daily draw falls outside the condition of the energy figure. The water heater selector filters by fuel, space and size.

The running cost is not stated here because it depends on your own electricity rate. The quantity to multiply by that rate is the 3,493 kWh at the medium draw pattern. The cost calculator takes your ZIP and applies your local tariff to this model. The installed price range on this page is a modeled range with its own source and date. It is not a quote. If you need a unit in the same class, the replacement finder starts from a model number. The class median of 3,531 kWh rests on the same electricity basis, so both figures scale with your rate.