TAKAGI TK-310U-I 2**

This site calculated the 209 therms figure. The registry does not list it. The calculation uses the registry'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. For the TAKAGI TK-310U-I 2**, the listed UEF is 0.81. The source is DOE's Compliance Certification Database (CCD), retrieved 2026-09-19. Your household's daily hot-water use may not match the test draw. If it doesn't, your yearly gas use may be higher or lower than 209 therms. This page has no data on how your use compares with the test draw. The steps behind the figure are set out in how the annual cost is calculated.

The high draw pattern represents a larger household, or one where showers and laundry overlap. The 209 therms figure describes a home with that kind of use. The registry lists this unit's maximum flow rate in gallons per minute as 4.7. That rate may or may not cover the fixtures you run at the same time. It depends on their own flow rates, and this data does not include them. The figure does not describe homes with lighter daily use. This page has no energy use figures for this model at other draw patterns. If you are checking whether the unit fits a smaller home, the rating on this page cannot tell you.

The rank given above, 323rd of 397, puts this model near the high-use end of its class. Most other gas tankless units at the high draw pattern use less gas at the same test draw. If you want a unit in the same class that uses less gas, you can find a same-class replacement by model number. The running cost does not appear in this text because it depends on your state's average residential gas price. The page calculates it from your ZIP. You can run it again in the cost calculator on your own ZIP. The installed price range has its own block on this page, with its source and date. That range comes from a cost model and is not a quote.