A. O. SMITH HPACO-45 1**+AXST-80 1**
3.8 UEF DOE CCD · 2026-09-19Grade C: where this UEF sits among the 194 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
An electric tank, high draw pattern (a larger household, or one where showers and laundry overlap).
If you are verifying this unit, its annual energy use is 1,306 kWh of electricity at the high draw pattern, the standard daily hot-water usage DOE tests against. That equals the class median of 1,306 kWh, a difference of 0 kWh, among 194 electric tank models.
Energy use per year
1,306 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 equal to the median of 1,306 kWh for the 194 models registered in the same heater type and draw pattern; it ranks 89 of 194, lowest energy first.
Solid line: this model (1,306 kWh). Dashed line: the class median.
Min 1,002 kWh Median 1,306 kWh Max 5,334 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
- 3.8 DOE CCD · 2026-09-19 Compared only with other models registered as an electric tank at the high draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- High 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
- 95 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 73 gal DOE CCD · 2026-09-19
- On the market since (ENERGY STAR) the date the manufacturer told ENERGY STAR the model went on sale
- 2026-02-13 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-744 (CO2), GWP 1 ENERGY STAR · 2026-09-19
What it costs to install
$3,938–$4,714 installed
Not a quote — a modeled range of what installers have charged for this class of unit; your price will vary with labor rates, access, and local code requirements.
Escalation indexes: equipment (BLS PPI) latest available: August 2026; labor (BLS ECI) latest available: April 2026 to June 2026.
NLR REMDB (BLS PPI/ECI escalated) · 2026-04-01Safety 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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All CO₂ (R-744) heat pump water heaters
Heat pump models whose ENERGY STAR filing names R-744 (carbon dioxide) as the refrigerant, a global warming potential of 1.
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Every A. O. SMITH model on file
What this brand files, by heater type.
UEF 3.8 · Grade C Price it on your ZIP
The figure of 1,306 kWh a year is computed by this site, not by the registry. It starts from the registry's UEF, the ratio of hot water delivered to energy used, which is 3.8 for A. O. SMITH HPACO-45 1**+AXST-80 1**. It also uses the DOE test's daily hot-water draw for the high draw pattern. The heater is an electric tank, so the fuel is electricity. The figure applies only to that test draw. Real use in a home changes with how much hot water the household draws. The source is the DOE CCD, retrieved 2026-09-19. The method behind the annual calculation is documented on its own page.
This unit is compared with the 194 models registered as an electric tank at the high draw pattern. It ranks 89th lowest for energy use, which places it in the second-lowest quarter of its class. The class median is 1,306 kWh, so the difference is 0 kWh. The high draw pattern describes a larger household, or one where showers and laundry overlap. The registry lists a first hour rating, the gallons of hot water available in the first hour from a full tank, of 95 gallons. The rated volume is 73 gallons. These figures help you check the unit against that kind of peak demand. This page has no figures for other draw patterns, so a smaller household should compare within its own pattern.
The running cost is not stated in the text, because it depends on your own utility electricity rate. Multiplying 1,306 kWh by that rate gives the yearly cost at the test draw. The cost calculator for your own ZIP does this for you. A modeled installed-cost range appears in its own block on this page, with its source and date. It is a range, not a quote. If you need a unit in the same class, you can find a same-class replacement by model number and start from HPACO-45 1**+AXST-80 1**. Your actual use may be higher or lower than 1,306 kWh. This page has no measured figure for your home.
DOE CCD · 2026-09-19