JOHN WOOD GPDL-40 3**

The figure of 163 therms is computed by this site, not the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, of 0.68 with the DOE test's daily hot-water draw for the medium draw pattern. The data source is DOE CCD, retrieved 2026-09-19. The result sits 22 therms below the class median of 185 therms. That gives the model 5th lowest energy use of 288, which is in the lowest quarter of its class. The comparison covers only models registered as a gas tank at the medium draw pattern, so it says nothing about other fuels or other draw patterns.

The registry lists this model with a first hour rating, the gallons of hot water available in the first hour from a full tank, of 74 gallons and a rated volume of 38 gallons. The energy figure applies to a household whose use resembles the medium draw pattern, meaning a typical household on a busy morning. A household with hot-water use well above or below that draw should not read 163 therms as its own consumption, because the registry gives no measured use for individual homes. Energy use at other draw patterns is not available on this page. Whether the first hour rating meets a particular household's peak demand is not judged here. The water heater selector filters by fuel, space and size, and the same-class replacement search works from a model number.

The running cost is not stated in the text. It depends on the state average residential gas price, and no price is assumed here. The cost calculator applies the reader's ZIP to the 163 therms figure at the medium draw pattern. The methodology page explains how the annual cost is calculated. A gas rate above or below the state average changes the result in proportion to therms used. The 22 therms gap to the class median of 185 therms therefore converts to a cost difference at that same rate. The modeled installed-cost range, which is not a quote, is shown in its own block with its source and date.