TAKAGI T-H3-OS-N 1**

The 178 therms figure is calculated by this site. The registry does not publish it. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the daily hot-water draw in the DOE test. For this model the UEF is 0.95, and the draw used is the one set for the high draw pattern. The registry source is the DOE Compliance Certification Database, retrieved 2026-09-19. The figure describes gas use at the federal test's draw, not at the draw of any particular household. A home whose daily use differs from the test will use a different amount of gas. This page does not estimate that amount. The method behind these annual figures is set out in how the annual energy and cost figures are calculated.

The high draw pattern describes a larger household, or one where showers and laundry overlap. This model's place in the lowest quarter of its class applies only to that pattern. The registry lists a maximum flow rate in gallons per minute of 5.8. The registry data here does not show how that flow changes with incoming water temperature, so that is not available. The 178 therms figure does not describe a household whose daily use is well below the high pattern. Energy figures at other draw patterns are not available in this data. To compare other units, use the water heater selector by fuel, space and size. To find another unit in the same class, try the same-class replacement search by model number.

This page does not state a running cost in the text. The cost depends on your state's average residential gas price, so the page calculates it from your ZIP. The calculation uses the 178 therms figure, so the cost also assumes the test draw. The 4 therms gap to the class median, given above, is a difference in energy. What that gap costs also depends on your rate. To see the cost at your own rate, use the running cost calculator on 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.