TAKAGI TK-510CX3 1**

This site calculated the 209 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 0.81. The result describes gas use at the federal test's draw, not use in any particular home. It does not describe a home that draws more or less hot water than the test assumes. The source is the DOE CCD, retrieved 2026-09-19. Each step behind the figure is set out in how the annual energy and cost are calculated.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. The registry lists this unit's maximum flow rate in gallons per minute as 5. Its rank of 323rd among the 397 models registered as a gas tankless unit at the high draw pattern puts it in the highest quarter of its class for energy use. Most models in this class use less gas at the same test draw. A reader who is comparing on energy use alone should note that position. The data here does not show which of those lower-use models also match a flow rate of 5. To check models in the same class, use find a same-class replacement by model number.

The text does not state a running cost. The cost of 209 therms of natural gas depends on the reader's state average residential gas price. For that reason the page calculates it from the reader's ZIP. Readers in different states will see different costs for the same TAKAGI TK-510CX3 1**. The gap of 27 therms above the class median also becomes a cost only at the reader's own rate. The cost calculator for your own ZIP applies that rate. The installed-price range appears in its own block with its source and date. It is a modeled range, not a quote. The page cannot give actual bills for homes that draw more or less hot water than the test.