Lennox WHGS040S37PAXE****

This site calculated the 185 therms figure; the registry does not publish it. 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 pattern. For this model the UEF is 0.6. The source is the DOE CCD, retrieved 2026-09-19. The figure holds only at the federal test's daily draw. A household that uses more or less hot water each day will use a different amount of gas. The medium pattern stands for a typical household's daily use, including a busy morning. For the full calculation, see how the annual energy and cost figures are calculated.

Among the 288 gas tank models at the medium draw pattern, this unit ranks 89th for lowest energy use. The registry data places that rank in the lower-use half of the class, while its yearly use matches the class median of 185 therms. The unit has a rated volume of 38 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 64 gallons. It fits a household whose busiest hour of hot-water use stays within 64 gallons. If you are matching a unit in the same class, use the same-class replacement search by model number.

The 64-gallon first hour rating is the limit for households with a heavier peak hour. Their peak demand would exceed what this unit supplies in its first hour. Because this model ranks 89th of 288, other gas tank models in its class use less gas at the same test draw. This page does not state how many. The running cost is not given in this text. It depends on your state's average residential gas price, so the page calculates it from your ZIP code in the cost calculator for your own ZIP. The installed price appears in its own block, with its source and date. It is a modeled range, not a quote.