Noritz NRCR92DV (GQ-C2661WXQ-FF US)

The 173 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 draw for the high draw pattern. For this model the UEF is 0.98, from DOE CCD data retrieved 2026-09-19. The result holds only at that test draw. A home that uses more or less hot water each day will use a different amount of gas. The registry lists 397 gas tankless units at the high draw pattern. Among them, this model ranks 1st lowest for annual energy use. The method behind the annual energy and cost figures explains each step of the calculation.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. The registry gives this unit a maximum flow rate in gallons per minute of 4.7. That is the limit on how much hot water it can deliver at one time. The temperature rise behind that figure is not available in this data. A home whose fixtures together draw more than 4.7 at once is outside what this listing covers. A smaller household that uses less hot water than the test draw will not match the 173 therms figure. This data does not give how far its gas use would differ. To compare units by other fuels or sizes, use the water heater selector by fuel, space and size.

The text on this page does not state a running cost. The cost depends on your state's average residential natural gas price. The page therefore computes it from your ZIP instead of printing one figure for every reader. That computation starts from the same 173 therms at the high draw pattern. On any single gas rate, the 9 therms gap to the 182 therms class median keeps its direction in cost. You can rerun the figure in the cost calculator for your own ZIP. The installed price range appears in its own block with its source and date. It is a modeled installed-cost range, not a quote. To match a replacement within the same 397 models, use the same-class replacement search by model number.