A. O. SMITH UPVA-45E 1**

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.92 for this unit. This site computed 642 kWh from that UEF and the DOE test's daily hot-water draw for the very small draw pattern. The registry does not publish that annual figure itself. It covers electricity only and applies to the test's daily draw, not to your household's use. Ranked from lowest energy use, the unit is 249th of 271 models. That places it in the highest quarter of its class for energy use. Its figure sits 27 kWh above the class median of 615 kWh. The calculation is explained in how the annual cost is calculated.

The maximum flow rate in gallons per minute is 0.5 for this model. That limit fits the small loads this draw pattern describes: a single bathroom, or a point-of-use heater under a sink. For those uses, 642 kWh is the figure to check against the class median of 615 kWh. The figure does not describe a larger draw pattern, and this page has no value for one. If several fixtures would run at once, compare the flow limit of 0.5 gallons per minute against that demand. The water heater selector by fuel, space and size filters by those inputs. The registry data used here does not say how the unit performs outside the federal test.

The running cost is not written here. It depends on your own utility electricity tariff, which this text does not know. Multiply 642 kWh by your rate per kilowatt-hour to get the yearly cost at the test's draw. The cost calculator on your own ZIP does that step for you. A unit at the class median of 615 kWh would use 27 kWh less each year at the same draw and rate. The cost difference is that 27 kWh multiplied by your rate. The energy figure comes from DOE CCD, retrieved 2026-09-19. To look at other models in this class, use the same-class replacement finder by model number.