Lennox WHGS050T40NPXS****

The registry does not print the 242 therms figure. This site computes it from two DOE inputs. The first is the model's UEF, the ratio of hot water delivered to energy used. The second is the daily hot-water draw that the federal test sets for the high draw pattern. This model's registered UEF is 0.7. The source is DOE's Compliance Certification Database (CCD), retrieved 2026-09-19. The result applies only at that test draw. A home that uses more or less hot water each day will use a different amount of gas, and this page has no data on that amount. The steps are set out in how this site calculates annual energy and running cost.

The model has the 90th lowest energy use of the 414 models in its class. That class is every model registered as a gas tank at the high draw pattern, and its median is 260 therms a year. At 18 therms below that median, this unit is in the lowest quarter of its class for energy use. The high draw pattern stands for a larger household, or one where showers and laundry overlap. The model lists a rated volume of 48 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 81 gallons. The figures here do not cover a smaller household's lower daily draw, so energy use at that draw is not available. To compare another gas tank model at the same draw pattern, find a same-class replacement by model number.

The text on this page gives no running cost for this model. That cost depends on 242 therms of natural gas a year and your state's average residential gas price, so it changes by state. The page calculates it from your ZIP, and the cost calculator for your own ZIP shows the result. Like the energy figure, it assumes the daily draw for the high draw pattern. The installed price range has its own block, with its source and date. It is a modeled installed-cost range, not a quote. If the high draw pattern does not match your home, the water heater selector by fuel, space and size lists other models.