TAKAGI T-H3S-OS-N 1**

This site calculated the 180 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 hot-water draw for the high draw pattern. For this model the UEF is 0.94, from the DOE Compliance Certification Database, retrieved on 2026-09-19. The result holds only at that test draw. A household that uses more or less hot water will use more or less gas. Among the 397 gas tankless units registered at the high draw pattern, this model ranks 165th lowest for energy use. Its figure is 2 therms a year below the class median. The page on how the annual cost is calculated sets out the steps behind the figure.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. The 180 therms figure was calculated for that level of use. The registry also lists a maximum flow rate in gallons per minute of 5.3 for this unit. Whether that rating covers a given home depends on how many fixtures run at the same time. This page cannot see that. A home with lighter daily use does not match the test draw, so its gas use will differ from 180 therms. To compare other fuels or sizes, the selector by fuel, space and size filters registered models. To look up another unit in the same class, use find a same-class replacement by model number.

This text does not state the running cost. The cost depends on your state's average residential natural gas price, so the page calculates it from your ZIP. The same 180 therms gives a different yearly cost in each state, so this text names no amount. The cost calculator on your own ZIP applies your state's rate to this model's energy figure at the high draw pattern. The installed price range is shown in its own block on this page, with its source and date. It is a modeled installed-cost range, not a quote, and this text does not repeat it. The class comparison, 2 therms below the 182 therms median, measures energy use, not cost.