Rheem SPEX4208

The 609 kWh figure is computed by this site, not taken from the registry. It applies the registry's UEF, the ratio of hot water delivered to energy used, to the DOE test's daily hot-water draw for the very small draw pattern. For the SPEX4208, the UEF is 0.97, from DOE CCD data retrieved 2026-09-19. The result is a figure at test conditions, not a meter reading. A household that draws more or less hot water than the test assumes will use a different amount. The registry does not provide that amount. The steps behind the calculation are set out on the page explaining how the annual cost is calculated.

Among the 271 models registered as an electric tankless unit at the very small draw pattern, the SPEX4208 ranks 37th lowest in energy use. That places it in the lowest quarter of its class. Its gap to the class median of 615 kWh is 6 kWh a year, both at the test's daily draw. This class covers small units: a single bathroom, or a point-of-use heater under a sink. The registry lists its maximum flow rate in gallons per minute as 0.4. Uses beyond a single bathroom or a sink fall outside the draw pattern behind these figures. For those uses, the selector by fuel, space and size compares other classes. To match this unit within its own class, use the same-class replacement search by model number.

The text gives no running cost for the SPEX4208. That cost depends on your own utility's electricity tariff, so the page computes it from your ZIP instead of estimating it here. The input it uses is the 609 kWh figure at the very small draw pattern. You can apply your own rate with the cost calculator on your own ZIP. The same condition applies to the 6 kWh gap to the class median of 615 kWh. What that gap means for your bill depends on your rate, and this text does not have your rate. The installed price range has its own block with its source and date. It is a modeled range, not a quote.