GSW WATER HEATERS GPDT-50 3**

The registry lists this model at a UEF, the ratio of hot water delivered to energy used, of 0.72. This site computed the annual figure of 235 therms from that UEF and the DOE test's daily hot-water draw for the high draw pattern. The registry does not publish the annual figure itself. The source is the DOE CCD, retrieved 2026-09-19. Among the 414 models registered as a gas tank at the high draw pattern, this one ranks 50th lowest in energy use. That places it in the lowest quarter of its class. Its use is 25 therms below the class median of 260 therms. The figure describes the test's draw, not the use of any particular household.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The registry gives a first hour rating, the gallons of hot water available in the first hour from a full tank, of 79 gallons. The rated volume is 48 gallons. Those two values are the ones to compare with your own busiest hour. The energy figure of 235 therms suits a household whose use resembles that draw pattern. It fits less well where a household draws well below the test's daily volume, because actual use would then differ from it. The data here does not say by how much. To compare other fuels or sizes, the water heater selector by fuel, space and size filters by those inputs.

The running cost is not stated in this text. It depends on your state's average residential gas price, and a cost written without your rate would be an estimate. The cost calculator on your own ZIP applies that price to the 235 therms shown here. The steps behind the result are set out in how the annual cost is calculated. The modeled installed-cost range has its own block on this page, with its source and date, and it is a range, not a quote. Measured field consumption for this unit is not available. The 25 therms gap from the class median of 260 therms holds only at the test's draw.