Rheem SFT 199-1

The registry does not print the 188 therms figure. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used. The other input is the daily hot-water draw that the DOE test sets for the high draw pattern. For this model the UEF is 0.9, as listed in DOE's Compliance Certification Database, retrieved 2026-09-19. The figure therefore describes the federal test day, not a measured household. A home that draws less hot water than the test assumes will use less gas than 188 therms, and a home that draws more will use more. The data here does not say by how much. You can check each input on the page about how the annual cost is calculated.

Among the 397 gas tankless models registered at the high draw pattern, the Rheem SFT 199-1 ranks 218th for lowest energy use. That places it in the second-highest quarter of its class for energy use. The high draw pattern stands for a larger household, or one where showers and laundry overlap. The 188 therms figure fits that kind of home. The registry lists a maximum flow rate in gallons per minute of 5.3 for this unit. For a household with lighter daily use, the 188 therms figure does not apply. This page has no figure for other draw patterns, so that value is not available here. To compare units by fuel, space and size, use the water heater selector by fuel, space and size.

The running cost is not stated in this text. It depends on the average residential gas price in your state, so the page computes it from your ZIP. The same applies to the 6 therms a year this model uses above the 182 therms class median. What that difference costs depends on your own gas rate. The cost calculator for your own ZIP multiplies 188 therms by that rate. The installed price shown in its own block on this page is a modeled range with its own source and date. It is not a quote. To find another unit in the same class, use the same-class replacement search by model number.