JOHN WOOD GPVL-50 2**

This site calculates the 235 therms figure. It is not taken directly from the registry. 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. The rated UEF is 0.72, from DOE CCD data retrieved 2026-09-19. The figure applies only at that test draw. A home that uses more or less hot water will use more or less gas. Among the 414 gas tank models at the high draw pattern, this one ranks 50th lowest in energy use. That puts it in the lowest quarter of its class. The steps are explained on the page about how this site calculates annual energy and cost.

The high draw pattern represents a larger household, or one where showers and laundry overlap. This unit's first hour rating, the gallons of hot water available in the first hour from a full tank, is 79 gallons. Its rated volume is 49 gallons. A home that needs more than 79 gallons in its busiest hour is outside what this rating covers. A smaller household that uses less hot water than the test assumes will not match the 235 therms figure. The data here does not give energy use at lower draws, so that figure is not available. A home without a natural gas supply is outside this class. To compare other fuels, spaces or sizes, use the water heater selector by fuel, space and size.

Running cost is not stated in this text. It depends on your state's average residential gas price, so the page calculates it from your ZIP instead. Because of the 25 therms gap to the class median noted above, this unit's yearly gas cost at the test draw is lower than the median model's at the same rate. How much lower depends on your price per therm, which this text does not have. The cost calculator for your own ZIP applies your state rate to the 235 therms figure. The installed price range shown elsewhere on this page is a modeled range, not a quote. To match a replacement in the same class, use the page to find a same-class replacement by model number.