A. O. SMITH GPCT-40L 1**

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.9 for this model. This site did not read the annual figure from the registry. It computed 188 therms of natural gas from that UEF and the DOE test's daily hot-water draw for the high draw pattern, using DOE CCD data retrieved 2026-09-19. The figure holds only at that draw and for that fuel. The model ranks 1st lowest energy use of 414, which places it in the lowest quarter of its class. The steps behind the computation are described in how the annual cost is calculated.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The 188 therms figure applies to that use and to no other. The registry gives a first hour rating, the gallons of hot water available in the first hour from a full tank, of 86 gallons, and a rated volume of 38 gallons. A household that needs more than 86 gallons in one hour is outside what this rating covers. A household with lighter use is not described by the 188 therms figure, and this page has no value for other draw patterns. That value is not available here. The water heater selector filters by fuel, space and size.

The running cost is not stated on this page because it depends on your state average residential gas price. The energy figure stays at 188 therms for the high draw pattern, so only the rate changes the cost. The cost calculator applies the state average residential gas price for your ZIP to that figure. No cost is estimated here. An installed price range is also not published for GPCT-40L 1**. Its ratings, 86 gallons first hour rating and 38 gallons rated volume, lie outside the range the cost database's model was fitted on, and the range is not stretched past it. A same-class unit can be found through the replacement search by model number.