Rheem SPEX100T

This site computed the 603 kWh figure from registry data; the registry itself does not publish 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 this pattern. The registry lists a UEF of 0.98 for this unit, and the data was retrieved from the DOE CCD on 2026-09-19. The very small draw pattern covers small units, such as a single bathroom or a point-of-use heater under a sink. At a larger daily draw the annual figure would change, and this page has no value for that case. The full steps are described in our note on how the annual energy and cost figures are calculated.

Among the 271 electric tankless units registered at the very small draw pattern, this model ranks 10th lowest for energy use. That places it in the lowest quarter of its class, 12 kWh below the 615 kWh median. The registry also lists a maximum flow rate in gallons per minute of 1. A plumber confirming a point-of-use install can check that rating against the fixture it will serve. A household that needs several fixtures running at once falls outside the pattern behind the 603 kWh figure. The registry data here does not say how the unit performs at higher flows. To compare other units, see the water heater selector by fuel, space and size.

The running cost is not stated in this text, because it depends on your own utility electricity tariff. The page computes it from your ZIP and applies it to the 603 kWh figure. Since this unit uses 12 kWh less than the class median, the cost gap against a median unit also depends on your rate. The installed price range appears in its own block, with its source and date, as a modeled range rather than a quote. To run the figure on a different rate, use the cost calculator for your own ZIP. To check a same-class alternative, find a same-class replacement by model number.