Kepler JSG48-29PCH/180K

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.95 for this unit. This site combined that UEF with the DOE test's daily hot-water draw for the high draw pattern to reach 178 therms of natural gas a year. The registry does not publish that annual figure itself, so it is a computed value and not a measured one. Among the 397 models registered as a gas tankless unit at this draw pattern, the unit ranks 45th lowest in energy use. That places it in the lowest quarter of its class. The gap to the class median of 182 therms is 4 therms a year.

The figure suits a reader whose home matches the high draw pattern: a larger household, or one where showers and laundry overlap. The registry lists the maximum flow rate in gallons per minute as 5.2. The temperature rise behind that rating is not available here. The 178 therms does not describe a household with a different daily draw, and this page gives no figure for other draw patterns. Real use in a home can differ from the federal test, and this page does not estimate by how much. A reader comparing other sizes can use the water heater selector, which filters by fuel, space and size.

The running cost is not written in the text because it depends on the state average residential gas price, which differs from reader to reader. The cost calculator applies the price for your own ZIP to the 178 therms, and the method for the annual cost sets out the calculation. The energy figure rests on the DOE CCD, retrieved 2026-09-19, and it changes only if the registry entry changes. The installed price range has its own block on this page, with its source and date, as a modeled range and not a quote. To check a same-class unit by model number, use the replacement finder.