A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1)
A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) is a heat pump (hybrid electric) water heater from A. O. Smith with a 60 gallon rated tank and a 82 gallon first-hour rating at a 3.7 UEF — 1341 kWh/yr certified use, 59 in tall.
Our take
Eighteen catalog listings under 8 brand names — from Giant to John Wood — resolve to this CO₂ split system: outdoor compressor, 60-gallon indoor tank at a slim 18 inches across, R-744 refrigerant with a GWP of 1, and compressor operation down to 1 °F where integrated rivals quit in the mid-30s to 40s. Certified performance holds the class median UEF (3.70) with an 82-gallon first-hour rating 4 above the median, at about $228 a year High-draw. Connected-capable, 240 V / 20.2 A. The install is a two-piece project; the winter physics is the reward.
Best for: Full family capacity in spaces that freeze.
Trade-off: Split-system installation cost and complexity.
Efficiency
Uniform Energy Factor (UEF)
3.7
Annual electricity use
1341 kWh/yr
Recovery efficiency
435 %
General
Fuel
Electric
Capacity
First-hour rating
82 gal
Rated storage volume
60 gal
Draw pattern
High
Heat pump
Heat pump type
Split System HPWH
Refrigerant (GWP)
R-744 (CO₂) (GWP:1 | Lower GWP)
Compressor low-temp cutoff
1 °F
Installation
Input voltage
240
Max current draw
20.2 A
Smart features
Smart / connected capable
Yes
Dimensions
Height
59 in
Diameter
18 in
Certification
ENERGY STAR certified
Yes
Who is the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) for?
Its 82 gallon first-hour rating suits a
household of 5+ people under DOE sizing guidance.
Estimated running cost: about $228/year at the national
average electricity rate (1341 kWh/yr certified use).
Needs a 240 V circuit; at 20.2 A max draw plan for a 30 A breaker (NEC 125% continuous-load rule).
The heat pump compressor operates down to 1 °F ambient — below that, backup
elements take over.
Also sold as
The A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) is certified hardware that A. O. Smith and its partner brands
publish under 18 names. The same specifications apply to every
variant:
Is the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) ENERGY STAR certified?
Yes, the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) holds a current ENERGY STAR certification for water heating efficiency (UEF 3.7).
How much does the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) cost to run per year?
About $228 per year at national average energy rates, based on its certified annual energy use under the DOE test draw pattern. Your rate and usage change this figure.
What electrical circuit does the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) need?
The A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) runs on a 240 V circuit drawing up to 20.2 A; per the NEC 125% continuous-load rule plan for at least a 30 A breaker (check the installation manual for the required circuit).
Is the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) a smart water heater?
Yes, the A. O. Smith Split System Heat Pump 65-Gallon (HPACO-45 1-+AXST-66 1) is connected-capable, with app control and eligibility for most utility demand-response programs.
