LOCHINVAR ENT-55 1**

The 3,493 kWh a year is this site's calculation. The registry does not publish it. The calculation starts from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.93 for the ENT-55 1**. It then applies the daily hot-water draw that the DOE test sets for the medium draw pattern. The figure therefore holds only at that test draw, with electricity as the fuel. If a household uses more or less hot water than the test assumes, its total will be different. This data cannot show how large that difference would be. The registry values come from the DOE CCD, retrieved 2026-09-19. The steps are set out in how this site calculates annual energy and running cost.

The medium draw pattern stands for a typical household as DOE defines it. The 3,493 kWh figure applies to homes with that level of hot-water use. This tank has a rated volume of 55 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 72 gallons. The rating does not cover a home that needs more than 72 gallons in its busiest hour. The class rank has a limit too. This model ranks 153rd of 426, so the models ranked above it use less energy under the same test. If you are checking a swap, you can find a same-class replacement by model number and compare the ranks directly.

The running cost does not appear in this text because it depends on your own utility's electricity tariff. The yearly cost is 3,493 kWh multiplied by your rate per kilowatt-hour, and the page works it out from your ZIP code. The same applies to the 38 kWh gap below the class median. That gap also has a cost value that changes with your tariff, so there is no single figure for it. To see the result at your own rate, use the running cost calculator for your ZIP. The installed price range has its own block, which gives its source and date. That range is modeled and is not a contractor's quote. It does not change the 3,493 kWh figure.