MRCOOL MHWH199NCLU

This site calculates the 178 therms figure; the registry does not publish it. The calculation combines the registry's UEF, the ratio of hot water delivered to energy used, with the daily hot-water draw that the DOE test sets for the high draw pattern. This model's UEF is 0.95. The source is the DOE CCD, retrieved 2026-09-19. The result shows gas use at the test's draw, not at the draw of any particular home. This page has no figure for a household whose daily hot-water use differs from the test's. The steps behind the calculation are set out on the page that explains how the annual cost is calculated.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. This model's energy figure applies only to that kind of use. In its class, it ranks 45th lowest in energy use of 397 models, which puts it in the lowest quarter for energy use. At the test's draw, it uses 4 therms a year less than the class median. Its maximum flow rate in gallons per minute is 5.7. Whether that rate covers a given home depends on how many fixtures run at once, and the registry does not record that. The high-pattern figure does not describe a smaller household, and this page has no figure for other draw patterns. You can compare other gas tankless models with the selector by fuel, space and size.

The running cost is not stated in this text because it depends on the average residential gas price in the reader's state. The page calculates it from the reader's ZIP, using the same 178 therms at the high draw pattern. Readers in different states will see different costs for the MHWH199NCLU, but the energy figure stays the same. The 4 therms gap to the class median becomes a cost gap only at a given gas rate. Without that rate, the size of the cost gap is not available. To see the cost at your own rate, use the cost calculator for your own ZIP. The installed price range appears in its own block and is a modeled range, not a quote.