A. O. SMITH ENSB-30 1**
0.91 UEF DOE CCD · 2026-09-19Grade G: where this UEF sits among the 163 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
An electric tank, low draw pattern (a one- or two-person household).
If you are verifying the A. O. SMITH ENSB-30 1**, start with its energy use. This electric tank uses 2,466 kWh of electricity a year at the low draw pattern, the standard daily hot-water usage DOE tests against. That is 27 kWh above the 2,439 kWh class median, ranking 88th lowest of 163.
Energy use per year
2,466 kWh a year
Computed by this site from the registry's UEF and the federal test's daily hot-water draw for this draw pattern. What it costs depends on the electricity rate where you live.
That is above the median of 2,439 kWh for the 163 models registered in the same heater type and draw pattern; it ranks 88 of 163, lowest energy first.
Solid line: this model (2,466 kWh). Dashed line: the class median.
Min 724 kWh Median 2,439 kWh Max 2,550 kWh
What it costs to run where you live
What the registry files
- UEF (Uniform Energy Factor) how much hot water you get for each unit of energy the heater uses
- 0.91 DOE CCD · 2026-09-19 Compared only with other models registered as an electric tank at the low draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- Low DOE CCD · 2026-09-19
- First Hour Rating how many gallons of hot water the unit can deliver in one hour, starting from a full tank
- 50 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 27 gal DOE CCD · 2026-09-19
What it costs to install
Not published: Installed cost range
This model's UEF lies outside the range NLR REMDB's cost model was fitted on, and the range is not stretched past it.
The annual energy figure on this page does not depend on this range and is unaffected.
Safety record
No CPSC recall names this model.
Checked against the CPSC recall database. CPSC does not publish a model-level match for this product category, so this list is curated by hand from the manufacturer's recall filings.
CPSC · 2026-09-24What these figures mean
How this compares
The closest models in the same class — same fuel, type and draw pattern.
Keep going
How every figure on this page is calculated
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Find what replaces your water heater
Enter the model number off your old unit and see what is on file today, with the yearly cost difference.
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Find a water heater that fits
Three questions — fuel, hot water need, install space — narrow every model on file to the ones that fit.
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What a water heater costs to run
Prices a unit's efficiency against your own utility's filed tariff for your ZIP code.
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Is a 30-gallon water heater enough?
Answered from what models in this size actually file.
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Water heaters
Every model on file with the Department of Energy, by heater type.
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All electric resistance tank water heaters
Electric tanks that file a UEF below 2.0 — heated by elements, not a heat pump.
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Every A. O. SMITH model on file
What this brand files, by heater type.
UEF 0.91 · Grade G Price it on your ZIP
The 2,466 kWh figure is calculated by this site. The registry 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 the low pattern. This model's UEF is 0.91, taken from the DOE CCD and retrieved 2026-09-19. Because the figure assumes the test's daily draw, it applies only at that level of use. A household that draws more hot water each day will use more electricity than 2,466 kWh. This data does not show how much more. The full method is described in how the annual cost is calculated.
The class median in the summary comes from the 163 models registered as an electric tank at the low draw pattern. At rank 88th, this model is in the second-highest quarter of its class for energy use, above the class midpoint. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 50 gallons. Its rated volume is 27 gallons. DOE uses the low pattern for small households. For a larger household, the low-pattern figure is the wrong comparison, and this data has no ratings at other patterns. To check other tanks in the same class, use find a same-class replacement by model number.
The text gives no running cost. The yearly cost of 2,466 kWh depends on your own utility's electricity tariff. The cost calculator for your own ZIP applies your local rate to this model's figure. The cost of the 27 kWh gap to the class median also depends on that rate. No installed price range is published for this model. Its ratings lie outside the range the cost database's model was fitted on, and the page does not stretch that range to cover it. For another fuel or tank size, the selector by fuel, space and size lists other classes.
DOE CCD · 2026-09-19