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      12,000 BTU mini-split heat pump · 45M Series

      Carrier 37MARAQ12AA1

      Very good cooling efficiency and below average heating efficiency for a 12,000 BTU mini-split heat pump, but not rated for cold climates.

      Ranks #220 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $309 a year to run in a mixed climate like Atlanta.

      SEER2
      23.5 Cooling efficiency over a season
      Very good · beats 70%
      HSPF2
      9.5 Heating efficiency over a season
      Below average · beats 24%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Average · beats 62%
      Heat at 5°F
      7,700 BTU/h64% of its 47°F output
      Very good · beats 88%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 70% of mini-splits.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You often see nights below 0°F - it is not cold-climate certified.
      • You mainly need heat - its HSPF2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications12,000 BTU, R-454B
      General
      BrandCarrier
      Also sold asBryant, Payne, WeatherMaker, Midea
      Outdoor unit model37MARAQ12AA1
      Series45M Series
      TypeMini-split heat pump
      Nominal size12,000 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 better23.5 (range 23.5)
      EER2Efficiency at 95°F outdoors13.0
      Cooling capacity12,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.5
      Capacity at 47°F12,000 BTU/h
      Capacity at 17°F10,000 BTU/h
      Capacity at 5°F7,700 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.33
      ENERGY STAR cold climateNo
      Heating output as it gets colder64% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 45MAHAQ12XA1 at the standard test temperatures, in BTU/h:

      Certified matchups7 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.
      45MAHAQ12XA1 CARRIER23.513.09.57,700215323748
      615AHAQ12XA1 BRYANT23.513.09.57,700215323759
      D5MAHAQ12XA1 PAYNE23.513.09.57,700215323770
      D5MAHAQ12XA1 Weathermaker23.513.09.57,700215323781
      D5MAHAQ12XA1 MIDEA23.513.09.57,700215323792
      D5MAHAQ12XA1 BRYANT23.513.09.57,700218139568
      D5MAHAQ12XA1 CARRIER23.513.09.57,700218139555
      Yearly running cost in 10 large cities$242-$768

      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 37MARAQ12AA1?
      The Carrier 37MARAQ12AA1 is rated at up to 23.5 SEER2 and 13.0 EER2 for cooling and up to 9.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Carrier 37MARAQ12AA1 good for cold climates?
      It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 12,000 BTU model.
      How much does the Carrier 37MARAQ12AA1 cost to run per year?
      At its rated efficiency it costs about $242-$768 a year in electricity in large U.S. cities, depending on climate and local rates - for example $315 in Phoenix and $655 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 37MARAQ12AA1?
      ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use CARRIER 45MAHAQ12XA1, BRYANT 615AHAQ12XA1, PAYNE D5MAHAQ12XA1.
      What refrigerant does the Carrier 37MARAQ12AA1 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 $321/yrYou save $298/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 37MARAQ12AA1
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $321
      Current system, per year
      $619
      You save per year
      $298
      Payback
      15.1 years
      Net after 10 years
      -$1,525

      Cooling $180Heating $141Electricity used: 2,008 kWhSaved vs. a minimum-efficiency heat pump: $153

      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 12,000 BTU models

      See all 394 12,000 BTU mini-splits, ranked

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