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A. O. Smith CAHP-40

Ranked #41 of 47 in Best 240-Volt Heat Pump Water Heaters (2026). Here is every spec we scored, where it came from, and how it compares.

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AO

#41

A. O. Smith CAHP-40

Best for: Official UEF 3.6, first-hour rating 55 gallons, 36 gallons certified storage, ENERGY STAR connected-capable

2.9/10

What we like

ENERGY STAR lists this model as connected-capable

Watch out for

Lower official first-hour rating in this set (55 gallons)

Score breakdown

Uniform energy factor 36%

First-hour rating 28%

Certified storage volume 18%

Connected capable 18%

Uniform energy factor	3.6
First-hour rating	55 gallons
Certified storage volume	36 gallons
Connected capable	Yes
Uniform energy factor (ENERGY STAR UEF)	3.6
First-hour rating (ENERGY STAR)	55 gallons
Certified storage volume (ENERGY STAR)	36 gallons
Annual energy use (ENERGY STAR)	902 kWh/year
Annual energy use per gallon (computed)	25.1 kWh/year per gallon, computed as certified annual energy use ÷ certified storage volume
Connected capable (ENERGY STAR)	Yes
Heat pump type (ENERGY STAR)	240 Volt Integrated HPWH
Input voltage (ENERGY STAR)	240 V
Maximum current (ENERGY STAR)	22.0 A
Lower compressor cut-off temperature (ENERGY STAR)	37.0 °F
Draw pattern (ENERGY STAR)	Medium-Usage
Recovery efficiency (ENERGY STAR)	426%
Sound pressure level (ENERGY STAR)	Not listed
Tank height (ENERGY STAR)	66 in
Tank diameter (ENERGY STAR)	20 in
Refrigerant (ENERGY STAR)	R-134a
Certified model number	CAHP-40 2**
Official brand name on the ENERGY STAR record	A. O. Smith
Price	Check price

Check price at Amazon

Specs sources:

How it compares

Open the full comparison table

GE Profile PH80S10BNY01

#1 · Official UEF 4.5, first-hour rating 101 gallons, 80 gallons certified storage, ENERGY STAR connected-capable

A. O. Smith CAHP-80

#2 · Official UEF 3.88, first-hour rating 95 gallons, 81 gallons certified storage, ENERGY STAR connected-capable

GE Profile PH65S10BNY01

#3 · Official UEF 4.3, first-hour rating 86 gallons, 65 gallons certified storage, ENERGY STAR connected-capable

Ariston ARIHPWH-80-T

#4 · Official UEF 4.1, first-hour rating 88 gallons, 74 gallons certified storage, ENERGY STAR connected-capable

Lennox WHHP080T45MD240S

#5 · Official UEF 4.1, first-hour rating 88 gallons, 74 gallons certified storage, ENERGY STAR connected-capable

ACIQ ACIQ-80G-HP-WH

#6 · Official UEF 4, first-hour rating 91 gallons, 74 gallons certified storage, ENERGY STAR connected-capable

Bosch TR7000T - 80US

#7 · Official UEF 4, first-hour rating 91 gallons, 74 gallons certified storage, ENERGY STAR connected-capable

Midea MAHW-80VN3B

#8 · Official UEF 4, first-hour rating 91 gallons, 75 gallons certified storage, ENERGY STAR connected-capable

Rinnai REHP80W

#9 · Official UEF 4, first-hour rating 91 gallons, 75 gallons certified storage, ENERGY STAR connected-capable

American Standard ASHPWH-80

#10 · Official UEF 4.01, first-hour rating 87 gallons, 73 gallons certified storage, ENERGY STAR connected-capable

GE Profile PH50S10BNY01

#11 · Official UEF 4.5, first-hour rating 75 gallons, 50 gallons certified storage, ENERGY STAR connected-capable

GE Profile PH50S10BPY01

#12 · Official UEF 4.3, first-hour rating 77 gallons, 50 gallons certified storage, ENERGY STAR connected-capable

A. O. Smith CAHP-66

#13 · Official UEF 3.84, first-hour rating 83 gallons, 68 gallons certified storage, ENERGY STAR connected-capable

Lennox WHHP065T45MD240S

#14 · Official UEF 4.05, first-hour rating 77 gallons, 61 gallons certified storage, ENERGY STAR connected-capable

Midea MAHW-65VN3B

#15 · Official UEF 4, first-hour rating 80 gallons, 61 gallons certified storage, ENERGY STAR connected-capable

Rinnai REHP65W

#16 · Official UEF 4, first-hour rating 80 gallons, 61 gallons certified storage, ENERGY STAR connected-capable

Bosch TR7000T-65US

#17 · Official UEF 3.9, first-hour rating 80 gallons, 60 gallons certified storage, ENERGY STAR connected-capable

Senville SENWH-HP65US

#18 · Official UEF 3.9, first-hour rating 80 gallons, 60 gallons certified storage, ENERGY STAR connected-capable

Rheem PRO H80 T2 RH310UM

#19 · Official UEF 3.5, first-hour rating 87 gallons, 72 gallons certified storage, ENERGY STAR connected-capable

Noritz NHP-80-240

#20 · Official UEF 4.24, first-hour rating 82 gallons, 71 gallons certified storage

Bradford White RE2HP80-1NCTT

#21 · Official UEF 4, first-hour rating 88 gallons, 75 gallons certified storage

LG APHWC801M

#22 · Official UEF 3.9, first-hour rating 94 gallons, 72 gallons certified storage

Bradford White RE2HP65-1NCTT

#23 · Official UEF 4.2, first-hour rating 82 gallons, 65 gallons certified storage

GE Profile PH40S10BPY01

#24 · Official UEF 4.2, first-hour rating 64 gallons, 40 gallons certified storage, ENERGY STAR connected-capable

LG APHWC502M

#25 · Official UEF 4.2, first-hour rating 81 gallons, 53 gallons certified storage

Ariston ARIHPWH-50-T

#26 · Official UEF 3.83, first-hour rating 69 gallons, 45 gallons certified storage, ENERGY STAR connected-capable

Lennox WHHP050T45MD240S

#27 · Official UEF 3.83, first-hour rating 69 gallons, 45 gallons certified storage, ENERGY STAR connected-capable

Midea MAHW-50VN3B

#28 · Official UEF 3.75, first-hour rating 71 gallons, 46 gallons certified storage, ENERGY STAR connected-capable

Rheem PRO H65 T2 RH310UM

#29 · Official UEF 3.5, first-hour rating 75 gallons, 59 gallons certified storage, ENERGY STAR connected-capable

Rinnai REHP50W

#30 · Official UEF 3.75, first-hour rating 71 gallons, 46 gallons certified storage, ENERGY STAR connected-capable

ACIQ ACIQ-50G-HP-WH

#31 · Official UEF 3.75, first-hour rating 69 gallons, 47 gallons certified storage, ENERGY STAR connected-capable

Bosch TR7000T - 50US

#32 · Official UEF 3.75, first-hour rating 69 gallons, 47 gallons certified storage, ENERGY STAR connected-capable

Senville SENWH-HP50US

#33 · Official UEF 3.75, first-hour rating 69 gallons, 47 gallons certified storage, ENERGY STAR connected-capable

A. O. Smith HPTS-50

#34 · Official UEF 3.8, first-hour rating 65 gallons, 46 gallons certified storage, ENERGY STAR connected-capable

American Standard ASHPWH-50

#35 · Official UEF 3.75, first-hour rating 68 gallons, 45 gallons certified storage, ENERGY STAR connected-capable

GREE GRS-3.0Pd/TD50GANhA-D

#36 · Official UEF 4.02, first-hour rating 80 gallons, 55 gallons certified storage

A. O. Smith CAHP-50

#37 · Official UEF 3.68, first-hour rating 65 gallons, 46 gallons certified storage, ENERGY STAR connected-capable

State CSHP-50

#38 · Official UEF 3.68, first-hour rating 65 gallons, 46 gallons certified storage, ENERGY STAR connected-capable

Vaughn ME80HPT

#39 · Official UEF 3.48, first-hour rating 86 gallons, 74 gallons certified storage

Rheem PRO H50 T2 RH310UM

#40 · Official UEF 3.5, first-hour rating 67 gallons, 45 gallons certified storage, ENERGY STAR connected-capable

Bradford White RE2HP50-1NCTT

#42 · Official UEF 3.89, first-hour rating 65 gallons, 45 gallons certified storage

Noritz NHP-50-240

#43 · Official UEF 3.85, first-hour rating 68 gallons, 45 gallons certified storage

Rheem PRO H40 T2 RH310UM

#44 · Official UEF 3.5, first-hour rating 60 gallons, 36 gallons certified storage, ENERGY STAR connected-capable

Rheem PRO H50 T2 RH310BM

#45 · Official UEF 3.5, first-hour rating 67 gallons, 45 gallons certified storage

A. O. Smith FPTU-50

#46 · Official UEF 3.35, first-hour rating 66 gallons, 46 gallons certified storage

Vaughn ME50HPT

#47 · Official UEF 3.46, first-hour rating 58 gallons, 47 gallons certified storage