RELIANCE WATER HEATERS T-H3S-DV-N 1**

This site computes the 178 therms figure; the registry does not list it. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily draw for the high pattern. For this model the UEF is 0.95, from DOE's Compliance Certification Database, retrieved 2026-09-19. The figure holds only at that test draw. A home that uses more or less hot water will burn more or less gas. The class is the 397 models registered as a gas tankless unit at the high draw pattern. Against their median of 182 therms, this unit sits 4 therms lower, which places it 45th lowest for energy use. The data does not show how that gap changes at other draw levels. See how the annual cost is calculated for the method.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The 178 therms figure applies to that kind of household. The unit's maximum flow rate in gallons per minute is 5.4, the most hot water it is rated to deliver at once. A home whose simultaneous demand stays within 5.4 matches the conditions behind the rating. A home that runs more fixtures together than that rate allows falls outside them, and the registry does not say how the unit performs there. Households using less hot water than the test draw are also outside the stated figure; their gas use is not available from this data. Readers with a different household can compare other units with the selector by fuel, space and size.

The running cost is not written here because it depends on your state's average residential gas price. The page applies that price to the 178 therms yearly use, based on your ZIP. The cost calculator on your own ZIP shows the result. Readers in different states will see different costs for the same model. The 4 therms gap to the class median converts to cost the same way, at your own rate. The installed price range sits in its own block, with its source and date. It is a modeled range, not a quote. To check another model in the same class against these figures, use the tool to find a same-class replacement by model number.