Lennox WHGS050S40NPXS****

The 245 therms figure does not appear in the registry itself. This site computed it from the model's UEF, the ratio of hot water delivered to energy used, which the registry lists as 0.69. The second input is the daily hot-water draw that the DOE test sets for the high draw pattern. Both inputs come from the DOE Compliance Certification Database, retrieved 2026-09-19. The figure therefore holds only at that test draw. A household drawing more hot water than the test assumes will burn more gas, and a lighter household will burn less. The registry gives no figure for either case, so this page has no figure for use outside the test draw. The full steps are in how this site calculates annual energy and running cost.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. This model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 80 gallons. Its rated volume is 48 gallons. Among the 414 gas tank models at the same draw pattern, it ranks 130th lowest for energy use. That places it in the second-lowest quarter of its class. The ranking covers only that class and says nothing about other heater types or draw patterns. It also does not describe a household whose daily use is well below the high draw pattern. To see other models in the same class, use the same-class replacement search by model number.

The running cost is not stated in this text. It comes from the 245 therms a year at the test draw, priced at your state's average residential gas price. That price depends on your state, so the page computes the cost from your ZIP. The 15 therms a year by which this model sits below the 260 therms class median carries the same condition. Its cost value also depends on your rate. You can price the figure at your own rate with the water heater cost calculator for your ZIP. The installed price range appears in its own block, with its source and date. It is a modeled installed-cost range, not a quote.