A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) is a heat pump (hybrid electric) water heater from A. O. Smith with a 36 gallon rated tank and a 55 gallon first-hour rating at a 3.6 UEF — 902 kWh/yr certified use, 66 in tall.
Also sold as the A. O. Smith Heat Pump 40-Gallon (CAHP-40 2). This model is the same certified
hardware as the A. O. Smith Heat Pump 40-Gallon (CAHP-40 2), published under a
different brand — full details, comparisons, and pricing live on that page. The
certified figures below are identical.
Efficiency
Uniform Energy Factor (UEF)
3.6
Annual electricity use
902 kWh/yr
Recovery efficiency
426 %
General
Fuel
Electric
Capacity
First-hour rating
55 gal
Rated storage volume
36 gal
Draw pattern
Medium
Heat pump
Heat pump type
240 Volt Integrated HPWH
Refrigerant (GWP)
R-134a (GWP:1430)
Compressor low-temp cutoff
37 °F
Installation
Input voltage
240
Max current draw
22 A
Smart features
Smart / connected capable
Yes
Dimensions
Height
66 in
Diameter
20 in
Certification
ENERGY STAR certified
Yes
Who is the A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) for?
Its 55 gallon first-hour rating suits a
household of 2–3 people under DOE sizing guidance.
Estimated running cost: about $153/year at the national
average electricity rate (902 kWh/yr certified use).
Needs a 240 V circuit; at 22 A max draw plan for a 30 A breaker (NEC 125% continuous-load rule).
The heat pump compressor operates down to 37 °F ambient — below that, backup
elements take over.
Is the A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) ENERGY STAR certified?
Yes, the A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) holds a current ENERGY STAR certification for water heating efficiency (UEF 3.6).
How much does the A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) cost to run per year?
About $153 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 Heat Pump 40-Gallon (HPA10-40H45DV 2) need?
The A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) runs on a 240 V circuit drawing up to 22 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 Heat Pump 40-Gallon (HPA10-40H45DV 2) a smart water heater?
Yes, the A. O. Smith Heat Pump 40-Gallon (HPA10-40H45DV 2) is connected-capable, with app control and eligibility for most utility demand-response programs.
