RELIANCE WATER HEATERS ATM-160M-N 1**

The 178 therms figure is computed by this site, not taken from the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily hot-water draw for the high draw pattern. This model's UEF is 0.95, as listed in the DOE CCD, retrieved 2026-09-19. The yearly figure holds only at that test draw. A home that uses more hot water than the test assumes will burn more gas, and one that uses less will burn less. How much more or less is not available here, because the registry holds no usage data for individual homes. The steps behind the figure are set out in how the annual energy and cost are calculated.

The high draw pattern describes a larger household, or one where showers and laundry overlap. This model is compared with the 397 models registered as a gas tankless unit at that pattern. Its 45th place in energy use puts it in the lowest quarter of that class. The 4 therms gap to the class median applies under test conditions only. Its maximum flow rate in gallons per minute is 4.8, as rated in the registry. That rating does not describe any particular home's fixtures. A home whose simultaneous hot-water demand exceeds 4.8 falls outside what this rating covers. Models with other ratings can be filtered in the selector by fuel, space and size.

The running cost is not stated in this text. It depends on your state's average residential natural gas price, so the page computes it from your ZIP. At 178 therms a year under the high draw pattern, the cost rises or falls in step with that gas price. The 4 therms gap to the class median converts to cost the same way, so its value also depends on your rate. The installed-cost range appears in its own block, with its source and date; it is a modeled range, not a quote. To see the yearly cost on your own rate, use the cost calculator for your ZIP. To look up a model registered in the same class, search for a same-class replacement by model number.