ARISTON ENS40H-*

The 3,531 kWh figure is computed by this site, not published by the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, of 0.92 with the DOE test's daily hot-water draw for the medium draw pattern. The source is DOE CCD, retrieved 2026-09-19. The figure applies only to that draw pattern, which represents a typical multi-person household on a busy morning. A household that draws more or less hot water than the test will use more or less electricity than this figure shows. The calculation steps are set out in how the annual cost is calculated.

Among the 426 models registered as an electric tank at the medium draw pattern, this unit ranks 213th lowest in energy use. Its difference of 0 kWh from the class median of 3,531 kWh places it in the lower-middle quarter of the class. That suits a reader whose household matches the medium draw pattern and who wants energy use at the class typical. Capacity is a separate matter. The first hour rating, the gallons of hot water available in the first hour from a full tank, is 51 gallons, and the rated volume is 37 gallons. The test figure does not show how a household that draws more than 51 gallons in its busiest hour would fare. To compare by fuel, space and size, use the water heater selector.

The running cost is not written here because it depends on your own utility electricity tariff, and no tariff is part of the registry data. Multiply 3,531 kWh by your rate per kWh, or enter your ZIP in the cost calculator to have the page do it. That result still applies only to the medium draw pattern; actual use in your home is not available here. The modeled installed-cost range appears in its own block on this page, with its source and date, and it is a range, not a quote. If you need a unit of the same class, find a replacement by model number and compare its annual energy against 3,531 kWh.