Rheem SPEX75T

This site computed the 609 kWh figure; the registry does not list it. It starts from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.97 for this model. The other input is the DOE test's daily hot-water draw for the very small draw pattern. The registry values come from the DOE Compliance Certification Database (CCD), retrieved 2026-09-19. The figure holds only at that test draw, so a different daily volume gives a different result. There are 271 electric tankless models registered at the very small draw pattern. Against them, this unit sits 6 kWh below the class median of 615 kWh a year. The page on how the annual figure is calculated sets out each step.

The very small draw pattern covers units that serve a bathroom on its own, or a point-of-use heater under a sink. The SPEX75T lists 0.7 as its maximum flow rate in gallons per minute. That is the limit on how much hot water it delivers at once. If fixtures running together call for more than 0.7, they fall outside what this rating describes. The 609 kWh figure does not describe a whole-house supply, because units tested at larger draw patterns belong to other classes. The water heater selector by fuel, space and size lists those classes. The rank of 37th lowest of 271 applies only within the very small electric tankless class.

The text gives no running cost, because the cost of 609 kWh a year depends on your own utility's electricity tariff. The page works it out from your ZIP instead. The cost calculator for your own ZIP runs the same step at any rate. That result still assumes the daily volume of the very small draw pattern, so it has the same condition as the energy figure. The installed price range has its own block, with its source and date. It is a modeled range, not a quote. If you are matching a unit that is already installed, you can find a same-class replacement by model number. You can then compare its energy use with the 615 kWh class median.