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

      Carrier 37MPRAQ12AA3

      Excellent cooling and heating efficiency for a 12,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #6 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $236 a year to run in a mixed climate like Atlanta.

      SEER2
      29.5 Cooling efficiency over a season
      Excellent · beats 98%
      HSPF2
      12.7 Heating efficiency over a season
      Excellent · beats 94%
      EER2
      14.3 Cooling efficiency on a 95°F day
      Very good · beats 86%
      Heat at 5°F
      13,500 BTU/h113% of its 47°F output
      Average · beats 48%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 98% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 13,500 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 94% 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

      Specifications12,000 BTU, R-454B
      General
      BrandCarrier
      Also sold asBryant, Payne, WeatherMaker, Midea
      Outdoor unit model37MPRAQ12AA3
      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 certifiedMarch 24, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better29.5 (range 29.5)
      EER2Efficiency at 95°F outdoors14.3
      Cooling capacity12,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better12.7
      Capacity at 47°F12,000 BTU/h
      Capacity at 17°F11,000 BTU/h
      Capacity at 5°F13,500 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder113% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 45MPHAQ12XA3 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.
      45MPHAQ12XA3 CARRIER · cold climate29.514.312.713,500215413143
      615PHAQ12XA3 BRYANT · cold climate29.514.312.713,500215413149
      D5MPHAQ12XA3 PAYNE · cold climate29.514.312.713,500215413155
      D5MPHAQ12XA3 Weathermaker · cold climate29.514.312.713,500215413161
      D5MPHAQ12XA3 MIDEA · cold climate29.514.312.713,500215413167
      D5MPHAQ12XA3 BRYANT · cold climate29.514.312.713,500218139617
      D5MPHAQ12XA3 CARRIER · cold climate29.514.312.713,500218139613
      Yearly running cost in 10 large cities$192-$580

      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 37MPRAQ12AA3?
      The Carrier 37MPRAQ12AA3 is rated at up to 29.5 SEER2 and 14.3 EER2 for cooling and up to 12.7 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Carrier 37MPRAQ12AA3 good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,500 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.
      How much does the Carrier 37MPRAQ12AA3 cost to run per year?
      At its rated efficiency it costs about $192-$580 a year in electricity in large U.S. cities, depending on climate and local rates - for example $246 in Phoenix and $492 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 37MPRAQ12AA3?
      ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use CARRIER 45MPHAQ12XA3, BRYANT 615PHAQ12XA3, PAYNE D5MPHAQ12XA3.
      What refrigerant does the Carrier 37MPRAQ12AA3 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 $249/yrYou save $370/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 37MPRAQ12AA3
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $249
      Current system, per year
      $619
      You save per year
      $370
      Payback
      12.2 years
      Net after 10 years
      -$803

      Cooling $143Heating $106Electricity used: 1,556 kWhSaved vs. a minimum-efficiency heat pump: $226

      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 24, 2026. How we use the data.