A. O. SMITH HPTA-40 2**
3.6 UEF DOE CCD · 2026-09-19Grade B: where this UEF sits among the 426 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
An electric tank, medium draw pattern (a typical three- or four-person household, about 55 gallons on a busy morning).
You are checking this unit's yearly energy use: A. O. SMITH HPTA-40 2** uses 902 kWh at the medium draw pattern, the standard daily hot-water usage DOE tests against. That is 2,629 kWh below the class median of 3,531 kWh, and it ranks 53rd lowest of 426 electric tank models.
Energy use per year
902 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 below the median of 3,531 kWh for the 426 models registered in the same heater type and draw pattern; it ranks 53 of 426, lowest energy first.
Solid line: this model (902 kWh). Dashed line: the class median.
Min 773 kWh Median 3,531 kWh Max 3,569 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
- 3.6 DOE CCD · 2026-09-19 Compared only with other models registered as an electric tank at the medium draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- Medium 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
- 55 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 36 gal DOE CCD · 2026-09-19
- On the market since (ENERGY STAR) the date the manufacturer told ENERGY STAR the model went on sale
- 2024-03-01 ENERGY STAR · 2026-09-19
- Connected / demand response (ENERGY STAR) whether the unit can take signals from your utility to shift when it heats, and by which standard (such as CTA-2045)
- Yes (CTA-2045-A,CTA-2045-B) ENERGY STAR · 2026-09-19
- Refrigerant and GWP (ENERGY STAR) the refrigerant a heat pump unit uses and its global warming potential, a leak's climate effect relative to carbon dioxide (CO2 = 1)
- R-134a, GWP 1430 ENERGY STAR · 2026-09-19
What it costs to install
Not published: Installed cost range
This model's rated tank size 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 · 2026-09-24Does it fit your space?
Enter your own numbers below — this compares them to what ENERGY STAR publishes for this model, it does not tell you what to buy.
- Compressor operating range (ENERGY STAR)
- the air temperatures around the unit in which its heat pump runs; outside this range the heat pump stops
- Dimensions (ENERGY STAR)
- the unit's filed height, width, depth or tank diameter, in inches
- Input voltage and maximum current (ENERGY STAR)
- the circuit voltage the unit is certified on and the most current it draws
What 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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What size heat pump water heater do I need?
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 heat pump water heaters
Electric tanks that file a UEF of 2.0 or more — the registry has no separate heat pump type, so this site draws the line there.
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Every A. O. SMITH model on file
What this brand files, by heater type.
UEF 3.6 · Grade B Price it on your ZIP
The annual energy figure is 902 kWh of electricity, and this site computed it rather than the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, of 3.6 with the federal test's daily hot-water draw for the medium draw pattern. The source is DOE CCD, retrieved 2026-09-19. Among the 426 models registered as an electric tank at the medium draw pattern, the median is 3,531 kWh. This model sits 2,629 kWh below that median. Its rank of 53rd lowest of 426 places it in the lowest quarter of its class for energy use. The figure holds for the test's daily draw and will differ with actual use.
The figure suits a household whose hot-water use resembles the medium draw pattern: a typical three- or four-person household on a busy morning. For that use, 902 kWh is the number to compare against other models at the same draw pattern. The unit has a rated volume of 36 gallons. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 55 gallons. The energy figure does not show whether those gallons cover a particular household's busiest hour. It also does not describe households whose daily use differs from the test draw, because this page holds no figure for other draw patterns. The water heater selector filters by fuel, space and size.
The running cost is not stated here because it depends on your own utility electricity tariff. The cost calculator applies the rate for your ZIP to the annual energy of 902 kWh, and the calculation method explains how the annual cost is worked out. Because this model is 2,629 kWh below the class median of 3,531 kWh, its energy cost is lower than the median model's at any single rate; the size of that gap in money depends on the rate. 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. To look at a same-class option, find a replacement by model number.
DOE CCD · 2026-09-19