Lennox WHES040S45TN240S****

The 3,531 kWh figure is computed by this site, not taken from the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily hot-water draw for the medium draw pattern. For this model the UEF is 0.92. The source is DOE CCD, retrieved 2026-09-19. The result holds only at that test draw. It does not describe a home that uses more or less hot water each day, and the data gives no value for other usage levels. The method behind the annual energy and cost figures sets out each step of the calculation.

The medium draw pattern stands for a typical mid-sized household on a busy morning. This model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 51 gallons, from a rated volume of 36 gallons. A household whose busiest hour needs more than 51 gallons falls outside what that rating covers. The class used here holds only the 426 electric tanks registered at the medium draw pattern. A comparison with gas units or with other draw patterns is therefore not like-for-like. The selector by fuel, space and size lists those other groups separately.

Running cost is not given in this text because it depends on your own utility's electricity tariff. The page computes it from your ZIP code with the cost calculator for your own ZIP code, applied to the 3,531 kWh test-draw figure. With a difference of 0 kWh from the class median, this model's cost at any single rate would match that of a median unit in its class. The installed price range sits in its own block with its source and date. It is a modeled range, not a quote. To compare against other units in the same class, use same-class replacements by model number.