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      2-ton central heat pump · 45M Series

      Carrier 37MUHAQ24AA3

      Very good cooling efficiency and excellent heating efficiency for a 2-ton central heat pump, and certified for cold climates.

      Ranks #68 of 331 2 ton central heat pumps for cooling efficiency, and costs about $646 a year to run in a mixed climate like Atlanta.

      SEER2
      18.7 Cooling efficiency over a season
      Very good · beats 80%
      HSPF2
      10.5 Heating efficiency over a season
      Excellent · beats 96%
      EER2
      12.0 Cooling efficiency on a 95°F day
      Average · beats 64%
      Heat at 5°F
      21,600 BTU/h86% of its 47°F output
      Average · beats 67%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 80% of central heat pumps.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 21,600 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 96% of central heat pumps.
      • 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

      Specifications2 ton, R-454B
      General
      BrandCarrier
      Also sold asBryant, WeatherMaker, Midea, Payne, PAYNE HEATING AND COOLING
      Outdoor unit model37MUHAQ24AA3
      Series45M Series
      TypeCentral heat pump
      Nominal size2 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceNovember 15, 2018
      Last certifiedSeptember 22, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better18.7 (range 16.0-18.7)
      EER2Efficiency at 95°F outdoors10.0-12.0
      Cooling capacity23,000-24,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.0-10.5
      Capacity at 47°F21,400-25,000 BTU/h
      Capacity at 17°F18,000-20,800 BTU/h
      Capacity at 5°F19,100-21,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-2.14
      ENERGY STAR cold climateYes
      Heating output as it gets colder86% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 45MUHAQ24XX3 at the standard test temperatures, in BTU/h:

      Certified matchups41 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.
      45MUHAQ24XX3 · cold climate18.712.010.020,600215318749
      45MUHAQ24XX3 · cold climate18.712.010.020,600215318777
      45MUHAQ24XX3 · cold climate18.712.010.020,600215318805
      45MUHAQ24XX3 · cold climate18.712.010.020,600215318833
      45MUHAQ24XX3 · cold climate18.712.010.020,600215318861
      D5FUHAH24XAK · cold climate18.712.010.020,600217557334
      D5FUHAH24XAK · cold climate18.712.010.020,600217557343
      D5FUHAH24XAK · cold climate18.712.010.020,600217730694
      D5FUHAH24XAK · cold climate18.712.010.020,600217730700
      D5FUHAH24XAK · cold climate18.712.010.020,600217730706
      45MUAAQ24XX3 · cold climate18.411.710.021,600215318748
      45MUAAQ24XX3 · cold climate18.411.710.021,600215318776
      45MUAAQ24XX3 · cold climate18.411.710.021,600215318804
      45MUAAQ24XX3 · cold climate18.411.710.021,600215318832
      45MUAAQ24XX3 · cold climate18.411.710.021,600215318860
      D5MUWAQ24XA3 · cold climate17.511.010.519,600217730631
      D5MUWAQ24XA3 · cold climate17.511.010.519,600217730647
      D5MUWAQ24XA3 · cold climate17.511.010.519,600217730663
      D5MUWAQ24XA3 · cold climate17.511.010.519,600217730679
      D5MUWAQ24XA3 · cold climate17.511.010.519,600217730615
      FT5ANXB24L · cold climate17.011.09.019,100216727309
      FT5ANXB24L · cold climate17.011.09.019,100216728037
      PF5TNXB24L · cold climate17.011.09.019,100216728040
      45MULAQ24XAX · cold climate16.010.09.521,000217456382
      45MULAQ24XBX · cold climate16.010.09.521,000217456383
      45MULAQ24XAX · cold climate16.010.09.521,000217456354
      45MULAQ24XAX · cold climate16.010.09.521,000217456298
      45MULAQ24XAX · cold climate16.010.09.521,000217456326
      45MULAQ24XBX · cold climate16.010.09.521,000217456327
      45MULAQ24XBX · cold climate16.010.09.521,000217456355
      45MULAQ24XBX · cold climate16.010.09.521,000217456299
      45MULAQ24XBX · cold climate16.010.09.521,000217456411
      45MULAQ24XAX · cold climate16.010.09.521,000217456410
      45MULBQ24XAX · cold climate16.010.09.521,000218792382
      45MULBQ24XBX · cold climate16.010.09.521,000218792381
      45MULBQ24XAX · cold climate16.010.09.521,000218792368
      45MULBQ24XBX · cold climate16.010.09.521,000218792367
      45MULBQ24XAX · cold climate16.010.09.521,000218792354
      45MULBQ24XBX · cold climate16.010.09.521,000218792353
      45MULBQ24XAX · cold climate16.010.09.521,000218792340
      45MULBQ24XBX · cold climate16.010.09.521,000218792339
      Yearly running cost in 10 large cities$602-$1,525

      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 37MUHAQ24AA3?
      The Carrier 37MUHAQ24AA3 is rated at up to 18.7 SEER2 and 12.0 EER2 for cooling and up to 10.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 41 certified matchups SEER2 ranges from 16.0-18.7.
      Is the Carrier 37MUHAQ24AA3 good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 21,600 BTU/h at 5°F with a COP of 2.14, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the Carrier 37MUHAQ24AA3 cost to run per year?
      At its rated efficiency it costs about $602-$1,525 a year in electricity in large U.S. cities, depending on climate and local rates - for example $730 in Phoenix and $1,265 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 37MUHAQ24AA3?
      ENERGY STAR lists 41 certified combinations for this outdoor unit. The highest-rated ones use 45MUHAQ24XX3, D5FUHAH24XAK, 45MUAAQ24XX3.
      What refrigerant does the Carrier 37MUHAQ24AA3 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 $718/yrYou save $535/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 37MUHAQ24AA3
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $718
      Current system, per year
      $1,254
      You save per year
      $535
      Payback
      16.8 years
      Net after 10 years
      -$3,646

      Cooling $452Heating $267Electricity used: 4,490 kWhSaved vs. a minimum-efficiency heat pump: $246

      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 2 ton models

      See all 331 2 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of September 22, 2026. How we use the data.