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      9,000 BTU mini-split heat pump · 45M Series

      Carrier 37MAHAQ09AA3

      Excellent cooling and heating efficiency for a 9,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #57 of 395 9,000 BTU mini-splits for cooling efficiency, and costs about $184 a year to run in a mixed climate like Atlanta.

      SEER2
      27.5 Cooling efficiency over a season
      Excellent · beats 96%
      HSPF2
      13.8 Heating efficiency over a season
      Excellent · beats 97%
      EER2
      15.5 Cooling efficiency on a 95°F day
      Excellent · beats 94%
      Heat at 5°F
      11,900 BTU/h96% of its 47°F output
      Below average · beats 22%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 96% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 11,900 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 97% of mini-splits.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • Nothing stands out - its ratings have no weak spot for its class.

      Calculate my running cost

      Details

      Specifications9,000 BTU, R-454B
      General
      BrandCarrier
      Also sold asBryant, Payne, WeatherMaker, Midea
      Outdoor unit model37MAHAQ09AA3
      Series45M Series
      TypeMini-split heat pump
      Nominal size9,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceNovember 15, 2018
      Last certifiedJune 1, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better27.5 (range 20.6-27.5)
      EER2Efficiency at 95°F outdoors13.5-15.5
      Cooling capacity9,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.9-13.8
      Capacity at 47°F9,000-12,000 BTU/h
      Capacity at 17°F9,000-12,000 BTU/h
      Capacity at 5°F10,600-11,900 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-1.89
      ENERGY STAR cold climateYes
      Heating output as it gets colder96% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 45MAHAQ09XA3 at the standard test temperatures, in BTU/h:

      Certified matchups32 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.
      45MAHAQ09XA3 CARRIER · cold climate27.515.512.511,500215323743
      615AHAQ09XA3 BRYANT · cold climate27.515.512.511,500215323754
      D5MAHAQ09XA3 PAYNE · cold climate27.515.512.511,500215323765
      D5MAHAQ09XA3 Weathermaker · cold climate27.515.512.511,500215323776
      D5MAHAQ09XA3 MIDEA · cold climate27.515.512.511,500215323787
      D5MAHAQ09XA3 BRYANT · cold climate27.515.512.511,500218139563
      D5MAHAQ09XA3 CARRIER · cold climate27.515.512.511,500218139550
      45MBFAQ09XA3 CARRIER · cold climate27.315.210.911,300215323801
      45MBFAQ09XA3 BRYANT · cold climate27.315.210.911,300215323862
      45MBFAQ09XA3 PAYNE · cold climate27.315.210.911,300215323923
      45MBFAQ09XA3 Weathermaker · cold climate27.315.210.911,300215323984
      45MBFAQ09XA3 MIDEA · cold climate27.315.210.911,300215324045
      45MCCAQ12XA3 CARRIER · cold climate24.014.712.210,600215323799
      45MCCAQ12XA3 BRYANT · cold climate24.014.712.210,600215323860
      45MCCAQ12XA3 PAYNE · cold climate24.014.712.210,600215323921
      45MCCAQ12XA3 Weathermaker · cold climate24.014.712.210,600215323982
      45MCCAQ12XA3 MIDEA · cold climate24.014.712.210,600215324043
      45MBCAQ12XA3 CARRIER · cold climate22.714.012.211,000215323800
      45MBCAQ12XA3 BRYANT · cold climate22.714.012.211,000215323861
      45MBCAQ12XA3 PAYNE · cold climate22.714.012.211,000215323922
      45MBCAQ12XA3 Weathermaker · cold climate22.714.012.211,000215323983
      45MBCAQ12XA3 MIDEA · cold climate22.714.012.211,000215324044
      45MBDAQ12XA3 CARRIER · cold climate21.513.512.511,200215323802
      45MBDAQ12XA3 BRYANT · cold climate21.513.512.511,200215323863
      45MBDAQ12XA3 PAYNE · cold climate21.513.512.511,200215323924
      45MBDAQ12XA3 Weathermaker · cold climate21.513.512.511,200215323985
      45MBDAQ12XA3 MIDEA · cold climate21.513.512.511,200215324046
      45MBDAQ12XH3 CARRIER · cold climate20.614.013.811,900215323803
      45MBDAQ12XH3 BRYANT · cold climate20.614.013.811,900215323864
      45MBDAQ12XH3 PAYNE · cold climate20.614.013.811,900215323925
      45MBDAQ12XH3 Weathermaker · cold climate20.614.013.811,900215323986
      45MBDAQ12XH3 MIDEA · cold climate20.614.013.811,900215324047
      Yearly running cost in 10 large cities$154-$449

      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 37MAHAQ09AA3?
      The Carrier 37MAHAQ09AA3 is rated at up to 27.5 SEER2 and 15.5 EER2 for cooling and up to 13.8 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 32 certified matchups SEER2 ranges from 20.6-27.5.
      Is the Carrier 37MAHAQ09AA3 good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,900 BTU/h at 5°F with a COP of 1.89, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the Carrier 37MAHAQ09AA3 cost to run per year?
      At its rated efficiency it costs about $154-$449 a year in electricity in large U.S. cities, depending on climate and local rates - for example $195 in Phoenix and $379 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 37MAHAQ09AA3?
      ENERGY STAR lists 32 certified combinations for this outdoor unit. The highest-rated ones use CARRIER 45MAHAQ09XA3, BRYANT 615AHAQ09XA3, PAYNE D5MAHAQ09XA3.
      What refrigerant does the Carrier 37MAHAQ09AA3 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 $196/yrYou save $284/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 37MAHAQ09AA3
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $196
      Current system, per year
      $480
      You save per year
      $284
      Payback
      12.3 years
      Net after 10 years
      -$659

      Cooling $115Heating $81Electricity used: 1,227 kWhSaved vs. a minimum-efficiency heat pump: $175

      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.

      Similar 9,000 BTU models

      See all 395 9,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 1, 2026. How we use the data.