A. O. SMITH ENLB-40W 1**
0.9 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).
Checking this water heater's numbers? The A. O. SMITH ENLB-40W 1** uses 2,494 kWh of electricity a year at the low draw pattern, the standard daily hot-water usage DOE tests against. It represents a one- or two-person household. That is 55 kWh above the class median of 2,439 kWh.
Energy use per year
2,494 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 122 of 163, lowest energy first.
Solid line: this model (2,494 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
- 0.9 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
- 38 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 35 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 0.9 · Grade G Price it on your ZIP
The annual figure of 2,494 kWh is electricity use under the federal test's low draw pattern. It is not a measurement taken in a home. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.9 for this model, and from the test's daily hot-water draw for this pattern. The source is DOE CCD, retrieved 2026-09-19. Among the 163 models registered as an electric tank at the low draw pattern, this one ranks 122nd lowest for energy use. That places it in the second-highest quarter of its class, 55 kWh above the class median of 2,439 kWh.
The figure applies to a household that matches the low draw pattern. This model has a first hour rating, the gallons of hot water available in the first hour from a full tank, of 38 gallons. Its rated volume is 35 gallons. A household with heavier daily use than the low draw pattern would not find 2,494 kWh to be its own figure. This page has no annual energy value for any other draw pattern, so none is given. The water heater selector filters by fuel, space and size, and all water heater pages lists the other models.
The running cost is not stated in the text, because it depends on your own utility electricity tariff. The cost calculator applies your ZIP to the 2,494 kWh figure. The 55 kWh gap above the class median is extra electricity per year, and its cost is your rate multiplied by that energy. The steps behind the calculation are in the annual cost methodology. An installed price range is not published for this model. Its ratings lie outside the range the cost database's model was fitted on, and the range is not stretched past it. Any cost you calculate carries the same condition as the energy figure: the low draw pattern at the federal test's daily draw.
DOE CCD · 2026-09-19