Lennox WHGS050S40*AXE****

The 260 therms figure is calculated by this site. The registry does not publish it. The calculation uses the registry's UEF, the ratio of hot water delivered to energy used, and the DOE test's daily hot-water draw for the high draw pattern. This model's UEF is 0.65, from the DOE CCD, retrieved 2026-09-19. The class has 414 models registered as a gas tank at the high draw pattern. At that draw, this unit ranks 204th lowest in energy use of the 414. That rank puts it in the second-lowest quarter of its class. Its difference from the class median is 0 therms. The steps behind the figure are set out in how this site calculates annual energy and cost.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. The 260 therms figure describes use at that draw only. The model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 78 gallons. Its rated volume is 48 gallons. For a household that draws less hot water, the registry gives no separate figure for this model. Its energy use at a lower draw is therefore not available on this page. Your actual daily hot-water use is also unknown to this page. To compare other units by these measures, use the water heater selector by fuel, space and size.

The text on this page gives no running cost. The cost of 260 therms of natural gas a year depends on your state's average residential gas price. The page works that cost out from your ZIP in the running cost calculator for your own ZIP. The class comparison above still applies here. At the same gas price, a model with the class median of 260 therms would cost the same to run each year. A modeled range for installed cost appears in its own block, with its source and date. That range is not a quote. None of these figures describe use above or below the federal test's daily draw.