Water Heaters
A. O. SmithHPACO-45C 1**+AXST-66CTTP 1**
ENERGY STAR certified · Mar 2026
- Annual energy use
- 1341 kWh/yr
- Tank size
- 60 gal
- Uniform energy factor
- 3.7
Running cost calculator
Where your state sits among all 51
Cost to run a water heater in every state
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How this is calculated
- Annual energy use is the figure ENERGY STAR lists for this model under typical test conditions. It is not measured in your home.
- Yearly cost = annual kWh × your rate. Monthly cost is the yearly cost divided by 12, a flat average. Five-year cost keeps the rate constant; prices will change.
- Statewide averages are not your utility’s tariff. Use your bill’s rate for a closer number.
- We do not estimate watts or hourly cost: the source data does not include them.
How it compares
Among 89 ENERGY STAR certified split system HPWH models with a similar tank size (45 to 75 gal), this one ranks 72nd lowest in annual energy use.
- Median of these models
- 923 kWh/yr
- This model vs the median
- +45%
- Uses less than
- 0% of them
Compared with every comparable model on the ENERGY STAR list, not only the ones published on this site. Same type, similar size.
Same type and size, lower energy use
| Model | kWh/yr | Difference |
|---|---|---|
| GSW WATER HEATERS GHPCO-45 1**+GXST-50LBTTP 1** | 915 | 915 kWh |
| Lochinvar LHPCO-45 1**+LXST-50LBTTP 1** | 915 | 915 kWh |
| American MHPCO-45 1**+MXST-50LBTTP 1** | 915 | 915 kWh |
| A. O. Smith HPACO-45 1**+AXST-50LBTTP 1** | 915 | 915 kWh |
| Giant GTHPCO-45 1**+GTXST-50LBTTP 1* | 915 | 915 kWh |
Yearly cost by state
Same 1341 kWh/yr at each state’s average residential price (2026-07).
Comparable models
Same type, within 25% of this model’s tank size.
Specifications
- Annual energy use
- 1341 kWh/yrENERGY STAR estimated annual electricity use for the rated usage pattern
- Tank size
- 60 galStorage volume
- Uniform energy factor
- 3.7 Uniform Energy Factor
- Type
- Split System HPWH
- Rated usage
- High-Usage
- First-hour rating
- 82 gal
- Electric input
- 4.5 kW
- Maximum amps
- 20.2
- Input voltage
- 240
- Tank height
- 59 in
- Tank diameter
- 18 in
- Refrigerant
- R-744 (CO2)
- Refrigerant and GWP
- R-744 (CO₂) (GWP:1 | Lower GWP)
- Connected
- Yes
- Markets
- United States, Canada
- Available on market
- 2026-02-13
- ENERGY STAR ID
- 4529409
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Frequently asked questions
How much electricity does the A. O. Smith HPACO-45C 1**+AXST-66CTTP 1** use?
ENERGY STAR lists 1341 kWh per year under typical test conditions, as ENERGY STAR publishes it for the usage pattern of the rating. Your use will differ with household size, how much hot water you draw and the temperature of the room the heater sits in.
How much does it cost to run?
At statewide average residential prices, the listed annual use costs about $170.58 in Louisiana and $643.68 in Hawaii (EIA, 2026-07). Your own utility rate may be different; enter it in the calculator.
How does the A. O. Smith HPACO-45C 1**+AXST-66CTTP 1** compare with similar models?
Among 89 ENERGY STAR certified split system HPWH models with a similar tank size, it ranks 72nd lowest in annual energy use. Its 1341 kWh per year is 45% above the median of 923 kWh.
What does the uniform energy factor mean?
It is the hot water delivered for each unit of energy the water heater uses, so a higher number means lower running cost. This model is listed at 3.7. A heat pump water heater scores far above a conventional electric one because it moves heat instead of making it.
Learn more
Methodology and sources
Model data comes from the ENERGY STAR Certified Water Heaters dataset (EPA). Electricity prices are statewide average residential prices from the U.S. EIA, latest period July 2026. Values are stored locally and refreshed by scheduled imports. Missing values are left blank, never estimated.