AMERICAN GPCT-40L 1**

The registry lists this model with a UEF, the ratio of hot water delivered to energy used, of 0.9. This site combined that UEF with the DOE test's daily hot-water draw for the high draw pattern and computed 188 therms of natural gas a year. The registry does not publish that annual figure itself. The underlying data is from DOE CCD, retrieved 2026-09-19. The class median is 260 therms, so this model sits 72 therms below it and ranks 1st lowest in energy use of 414 models. The steps behind the calculation 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 first hour rating, the gallons of hot water available in the first hour from a full tank, is 86 gallons for this model, and its rated volume is 38 gallons. The 188 therms figure holds only at the federal test's daily draw. A household that draws more or less hot water than that test will use more or less gas, and this page has no measurement of the difference. Whether 86 gallons covers a particular household's busiest hour is not settled by the registry data. To compare other fuels, spaces or sizes, use the water heater selector.

The 188 therms figure is a quantity of gas, not a cost. Its cost depends on the state average residential gas price for the reader's ZIP, so this page does not state or estimate one. Because the model uses 72 therms less than the class median of 260 therms at the test draw, the same gas price gives it a lower annual cost than the median model, and the size of that gap depends on the rate. The cost calculator on your own ZIP applies that rate. An installed price range is not published, because this model's ratings lie outside the range the cost database's model was fitted on. To find a same-class model for GPCT-40L 1**, use the replacement lookup by model number.