AMERICAN ATI-180B-N 1**

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.82 for this unit. This site computed the annual figure of 206 therms; the registry does not state it. The inputs are the registry's UEF and the DOE test's daily hot-water draw for the high draw pattern. The fuel is natural gas, and the source is DOE CCD, retrieved 2026-09-19. The figure holds only at the federal test's draw. A different household draw would change the therms used, and this page has no measured data for any real home.

The unit holds the 229th lowest energy use of 397 models in its class. That places it in the second-highest quarter of its class for energy use. Its annual figure is 24 therms above the class median of 182 therms. The high draw pattern describes a larger household, or one where showers and laundry overlap. A household of that kind is the one this test draw represents. The registry lists a maximum flow rate in gallons per minute of 4.7. For a smaller household, the figure may not apply, and this page does not give the unit's use at other draw patterns.

The running cost is not stated in this text. It depends on your state's average residential gas price. The cost calculator on your own ZIP applies that price to 206 therms. See how the annual cost is calculated. At the same gas price and draw pattern, a unit using 182 therms costs less to run than one using 206 therms. The modeled installed-cost range appears in its own block with its source and date; it is not a quote. To compare alternatives, find a same-class replacement by model number using ATI-180B-N 1**.