A. O. SMITH GPDT-50 3**

The annual figure of 235 therms applies only at the high draw pattern, and this site computed it rather than the registry. The calculation takes the registry's UEF, the ratio of hot water delivered to energy used, which is 0.72 for this model, together with the DOE test's daily hot-water draw for that pattern. The source is DOE CCD, retrieved 2026-09-19. The gap of 25 therms to the class median gives this model a rank of 50th lowest energy use among 414 models, which is in the lowest quarter of its class. The methodology page sets out how the annual figures are calculated.

The high draw pattern describes a larger household, or one where showers and laundry overlap. This model has a first hour rating, the gallons of hot water available in the first hour from a full tank, of 79 gallons, and a rated volume of 48 gallons. Those ratings describe capacity, not efficiency, so a low energy figure does not show that the tank meets a given household's peak demand. A household whose busiest hour needs more hot water than 79 gallons falls outside what this rating describes, whatever the energy figure shows. The registry data used here does not include other draw patterns for this model, so a figure for a smaller household is not available. To filter by fuel, space and size, use the water heater selector.

Running cost is not stated in the text. It depends on the state average residential gas price, which differs by location, so the page computes it from the ZIP you enter. The 235 therms figure is the fixed input, and your gas price is the variable. The cost calculator applies your own rate to it. The installed price range appears in its own block, with its source and date, as a modeled installed-cost range and not a quote. To find a same-class replacement for GPDT-50 3**, you can search by model number. This page does not measure household use, so real consumption may differ from 235 therms, which holds only under the test conditions of the high draw pattern.