AMERICAN GUF-50 1**

The figure of 242 therms is not a registry entry. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.7 for this model, and from the DOE test's daily hot-water draw for the high draw pattern. The source is DOE CCD, retrieved 2026-09-19. The 414 models registered as a gas tank at the high draw pattern have a median of 260 therms, so this model sits 18 therms below it. It ranks 90th lowest in energy use among 414, which places it in the lowest quarter of its class. The comparison holds only for natural gas at the test's draw. It does not measure what this unit uses in a specific home.

The high draw pattern describes a larger household, or one where showers and laundry overlap. For this model the first hour rating, the gallons of hot water available in the first hour from a full tank, is 83 gallons, and the rated volume is 48 gallons. A household can compare those two values with its own busiest hour. The energy figure of 242 therms applies at the test's draw only. A household that uses more or less hot water than the high draw pattern will not use 242 therms, and this page has no figure for any other draw pattern. The water heater selector filters by fuel, space and size.

The running cost is not stated in the text, because it depends on the state average residential gas price, which differs by reader. Multiply 242 therms by your own price per therm, or enter your ZIP in the cost calculator, which does this for you. The methodology page explains how the annual cost is calculated. The 18 therms gap to the class median of 260 therms scales with the same rate, so its cost effect depends on your price. If you are matching a unit already installed, you can find a same-class replacement by model number and compare it with AMERICAN GUF-50 1**. The modeled installed-cost range appears in its own block on this page, with its source and date.