RELIANCE WATER HEATERS ATHR-199M 1**

This site computed the 178 therms figure. The registry does not publish it. The figure combines the model'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. The listed UEF of 0.95 comes from the DOE CCD, retrieved on 2026-09-19. The result holds only at that test draw. A home that draws more or less hot water each day will use a different amount of gas, and this data cannot give that amount. The class median uses the same test draw, so the comparison in the summary above uses matching conditions. The same inputs feed the cost figure, as set out in how the annual cost is calculated.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The 178 therms figure applies most directly to homes of that kind. The registry also lists a maximum flow rate in gallons per minute of 5.9 for this unit. That is the rated limit on hot water delivered at once, so demand above 5.9 falls outside what the listing covers. A smaller household with lighter daily use does not match the test draw, so the annual figure will not describe its use. This data does not say whether the rank of 45th among 397 models would hold at a lower draw. To check other units in the same class, use the same-class replacement search by model number.

The running cost is not stated in this text, because it depends on the reader's state average residential gas price. The page computes it from your ZIP, using that state price and the 178 therms figure at the high draw pattern. To see the result, enter a ZIP in the cost calculator for your own ZIP. Your cost will differ if your gas rate is not the state average or your household's hot-water use is not the test draw. This data cannot say by how much. The installed price appears in its own block, with its source and date. It is a modeled installed-cost range, not a quote, and it is not restated here.