RELIANCE WATER HEATERS T-H3-OS-N 1**

This site calculated the 178 therms figure; the registry does not list it. The calculation uses the model's UEF, the ratio of hot water delivered to energy used, and the DOE test's daily hot-water draw for the high draw pattern. This model's UEF is 0.95. Both inputs come from the DOE CCD, retrieved 2026-09-19. The figure holds only at that test draw. If your household uses more or less hot water than the test assumes, its gas use will differ. This page does not have that amount for your household. The steps are set out in how the annual cost is calculated.

The comparison group is the 397 models registered as a gas tankless unit at the high draw pattern. At the test draw, the 4 therms gap to the class median puts this model in the lowest quarter of its class for energy use. The registry data does not show how that gap changes at other draws. The high draw pattern describes a larger household, or one where showers and laundry overlap. This model's maximum flow rate in gallons per minute is 5.8. A smaller household with lower daily use should not read 178 therms as its own expected use, because the test used the high pattern. The selector by fuel, space and size covers other classes.

The text on this page does not state a running cost. The cost of 178 therms of natural gas depends on your state's average residential gas price. The page calculates it from your ZIP. Enter your ZIP in the cost calculator on your own ZIP to see the cost at your rate. At any single rate, this model's cost stays below the class median cost, because its gas use is 4 therms lower. The size of that cost difference depends on your price. The installed-cost range shown on this page is a modeled range, not a quote. It sits in its own block with its source and date. To compare a unit from the same class, use find a same-class replacement by model number.