Rheem SPEX90T

The 603 kWh figure was computed by this site, not taken from the registry. 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 model the registry lists a UEF of 0.98, and the draw is the one set for the very small draw pattern. The source is the DOE CCD, retrieved 2026-09-19, and the figure holds only at that test draw. A household whose daily hot-water use differs from the test draw will see a different annual figure from 603 kWh. The full method is described on the page on how this site calculates annual energy and cost.

Against the 271 models registered as an electric tankless unit 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 class median of 615 kWh a year. The gap applies only at the test draw for this class, so it does not describe use in larger households. The very small draw pattern covers small units: a single bathroom, or a point-of-use heater under a sink. The registry lists a maximum flow rate in gallons per minute of 0.9 for this model. A site that needs more flow than 0.9 gallons per minute falls outside what this rating covers. Readers who need a different size or fuel can use the water heater selector by fuel, space and size.

This page does not state a running cost in the text, because the cost of 603 kWh depends on the reader's own electricity tariff. The page therefore computes the cost from the reader's ZIP instead of estimating it. At any single rate, the cost gap to the class median follows from the 12 kWh energy difference at the test draw. To get that figure for a specific address, enter the ZIP in the running-cost calculator for your own ZIP. The installed price appears in its own block, with source and date, as a modeled range rather than a quote. Anyone matching a replacement to this model can find a same-class replacement by model number.