HVAC Rated

48,000 BTU mini-split heat pump · 45M Series

Carrier 37MBHAQ58AA3

Below average cooling efficiency and average heating efficiency for a 48,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #126 of 146 48,000 BTU mini-splits for cooling efficiency, and costs about $1,514 a year to run in a mixed climate like Atlanta.

SEER2
18.1 Cooling efficiency over a season
Below average · beats 5%
HSPF2
10.7 Heating efficiency over a season
Average · beats 68%
EER2
9.0 Cooling efficiency on a 95°F day
Below average · beats 1%
Heat at 5°F
54,000 BTU/h90% of its 47°F output
Average · beats 67%

A good fit if…

  • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 54,000 BTU/h at 5°F.
  • You want steady temperatures and quiet running - the compressor varies its speed.
  • You want a choice of indoor units - 15 certified pairings.

Think twice if…

  • Cooling cost matters most - its SEER2 is below average for mini-splits.

Calculate my running cost

Details

Specifications48,000 BTU, R-454B
General
BrandCarrier
Also sold asBryant, Payne, WeatherMaker, Midea
Outdoor unit model37MBHAQ58AA3
Series45M Series
TypeMini-split heat pump
Nominal size48,000 BTU
CompressorVariable-speed units run longer at low powerContinuously variable
RefrigerantR-454B
Connected (smart) capableNo
On the market sinceNovember 15, 2018
Last certifiedMarch 13, 2025
Cooling
SEER2Seasonal efficiency, higher is better18.1 (range 15.4-18.1)
EER2Efficiency at 95°F outdoors9.0-10.2
Cooling capacity54,000-55,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better9.2-10.7
Capacity at 47°F59,000-60,000 BTU/h
Capacity at 17°F41,000-45,000 BTU/h
Capacity at 5°F53,000-54,000 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater1.91-2.10
ENERGY STAR cold climateYes
Heating output as it gets colder90% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 45MCFAQ58XA3 at the standard test temperatures, in BTU/h:

Certified matchups15 indoor units

The same outdoor unit scores differently with each indoor unit. Ask your installer for the AHRI reference number of the exact system you are quoted.

Indoor unitSEER2EER2HSPF2Heat @5°FAHRI ref.
45MCFAQ58XA3 CARRIER · cold climate18.19.010.754,000215323848
45MCFAQ58XA3 BRYANT · cold climate18.19.010.754,000215323909
45MCFAQ58XA3 PAYNE · cold climate18.19.010.754,000215323970
45MCFAQ58XA3 Weathermaker · cold climate18.19.010.754,000215324031
45MCFAQ58XA3 MIDEA · cold climate18.19.010.754,000215324092
45MBDAQ58XH3 CARRIER · cold climate15.910.210.453,500215323849
45MBDAQ58XH3 BRYANT · cold climate15.910.210.453,500215323910
45MBDAQ58XH3 PAYNE · cold climate15.910.210.453,500215323971
45MBDAQ58XH3 Weathermaker · cold climate15.910.210.453,500215324032
45MBDAQ58XH3 MIDEA · cold climate15.910.210.453,500215324093
45MBAAQ60XA3 · cold climate15.410.09.253,000215318771
45MBAAQ60XA3 · cold climate15.410.09.253,000215318799
45MBAAQ60XA3 · cold climate15.410.09.253,000215318855
45MBAAQ60XA3 · cold climate15.410.09.253,000215318883
45MBAAQ60XA3 · cold climate15.410.09.253,000215318827
Yearly running cost in 10 large cities$1,399-$3,582

At each state's average electricity price and the city's typical heating and cooling hours.

Questions5
What is the SEER2 rating of the Carrier 37MBHAQ58AA3?
The Carrier 37MBHAQ58AA3 is rated at up to 18.1 SEER2 and 9.0 EER2 for cooling and up to 10.7 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 15 certified matchups SEER2 ranges from 15.4-18.1.
Is the Carrier 37MBHAQ58AA3 good for cold climates?
Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 54,000 BTU/h at 5°F with a COP of 2.10, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
How much does the Carrier 37MBHAQ58AA3 cost to run per year?
At its rated efficiency it costs about $1,399-$3,582 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,703 in Phoenix and $2,975 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Which indoor units work with the Carrier 37MBHAQ58AA3?
ENERGY STAR lists 15 certified combinations for this outdoor unit. The highest-rated ones use CARRIER 45MCFAQ58XA3, BRYANT 45MCFAQ58XA3, PAYNE 45MCFAQ58XA3.
What refrigerant does the Carrier 37MBHAQ58AA3 use?
It uses R-454B.

Running cost and savings

Pre-filled with this model. Pick your city and what you heat with today; everything else is optional.

Heat pump $1,678/yrYou save $1,204/yrSee details ↓
1. Where you live
Adjust heating and cooling hours

Filled in from your city's climate. Change them if you run the system much more or less than usual.

2. The heat pump Carrier 37MBHAQ58AA3
3. What it replaces
4. Price replace the example with your quote
Heat pump, per year
$1,678
Current system, per year
$2,883
You save per year
$1,204
Payback
17.0 years
Net after 10 years
-$8,457

Cooling $1,050Heating $628Electricity used: 10,489 kWhSaved vs. a minimum-efficiency heat pump: $547

Estimates use the unit's rated SEER2 and HSPF2, full-load hours derived from NOAA 1991-2020 degree days, average residential electricity prices from the U.S. EIA (12 months to July 2026) and fuel prices from EIA (2025 for natural gas, week of 2026-10-05 for propane and heating oil). Very cold days that need backup heat are not modelled. Federal minimum for comparison: 14.3 SEER2 / 7.5 HSPF2.

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Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 13, 2025. How we use the data.