A. O. SMITH UPVA-55E 1**

The figure of 642 kWh is computed by this site, not published by the registry. It starts from the registry's UEF, the ratio of hot water delivered to energy used. It then applies the DOE test's daily hot-water draw for this draw pattern. The registry lists a UEF of 0.92 for this model. The registry does not report annual energy directly, so the value is a calculation and not a measurement of your installation. That figure holds only at the very small draw pattern. The source is DOE CCD, retrieved 2026-09-19. The methodology page explains how the annual cost is calculated.

The comparison class is the 271 models registered as an electric tankless unit at the very small draw pattern. Its median is 615 kWh, and this model sits 27 kWh above it. That places it in the highest quarter of its class for energy use. The data does not say why it differs from the median. The very small draw pattern covers small units, meaning a single bathroom or a point-of-use heater under a sink. The maximum flow rate in gallons per minute is 0.5. For a household with a larger draw, this figure does not apply, and the page gives no value for that case.

The running cost depends on your own electricity rate, so the text does not state it. Multiplying 642 kWh by your rate gives a yearly cost at this draw pattern. The cost calculator does that from your ZIP. If your hot-water use differs from the federal test's draw, your real consumption will differ from 642 kWh. The installed price appears in its own block, with source and date, as a modeled range and not a quote. The 642 kWh figure is a like-for-like comparison only against models at the same draw pattern. To check another unit, find a same-class replacement by model number and compare it with the class median of 615 kWh.