FRIEDRICH RTGH-90DVLN-3

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.93 for this model. This site computed the annual figure of 182 therms, not the registry. It combines the registry's UEF with the DOE test's daily hot-water draw for the high draw pattern. The source is DOE CCD, retrieved 2026-09-19. This unit ranks 183rd lowest for energy use among the 397 models registered as a gas tankless unit at the high draw pattern. That places it in the second-lowest quarter of its class. The class median is 182 therms, so the difference from the median is 0 therms. The calculation steps are set out under how the annual cost is calculated.

The 182 therms figure applies only to the high draw pattern. A household with different hot-water use will see different gas use, and this page has no figure for other patterns. The maximum flow rate in gallons per minute is 4.9. That value comes from the registry. It does not state how many fixtures can run at once. The unit suits a reader checking a larger household against its class, since its use sits at the median of 182 therms. It shows no energy gain or loss against that median, because the difference is 0 therms. Readers with other needs can use the selector by fuel, space and size.

The running cost is not stated here because it depends on the state average residential gas price. The site multiplies the 182 therms of natural gas by that price. The same unit therefore costs different amounts in different states. Enter your ZIP in the cost calculator on your own ZIP to see the result for your rate. The installed-cost range has its own block on this page, with its source and date. It is a modeled range, not a quote. To compare against another unit at the high draw pattern, find a same-class replacement by model number. Field measurements of actual gas use for this model are not available.