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      18,000 BTU mini-split heat pump · C-Series

      AUX AM2-H18/2DR3B

      Average cooling efficiency and very good heating efficiency for a 18,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #133 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $423 a year to run in a mixed climate like Atlanta.

      SEER2
      23.3 Cooling efficiency over a season
      Average · beats 67%
      HSPF2
      11.0 Heating efficiency over a season
      Very good · beats 75%
      EER2
      12.5 Cooling efficiency on a 95°F day
      Average · beats 44%
      Heat at 5°F
      21,800 BTU/h121% of its 47°F output
      Average · beats 48%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 21,800 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 75% 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

      Specifications18,000 BTU, R-32
      General
      BrandAUX
      Outdoor unit modelAM2-H18/2DR3B
      SeriesC-Series
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceMay 30, 2024
      Last certifiedAugust 11, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better23.3 (range 23.3)
      EER2Efficiency at 95°F outdoors12.5
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.0
      Capacity at 47°F18,000 BTU/h
      Capacity at 17°F22,000 BTU/h
      Capacity at 5°F21,800 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder121% kept at 5°F

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

      Certified matchups1 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.
      - · cold climate23.312.511.021,800214097940
      Yearly running cost in 10 large cities$364-$1,022

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

      Questions4
      What is the SEER2 rating of the AUX AM2-H18/2DR3B?
      The AUX AM2-H18/2DR3B is rated at up to 23.3 SEER2 and 12.5 EER2 for cooling and up to 11.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the AUX AM2-H18/2DR3B good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 21,800 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 AUX AM2-H18/2DR3B cost to run per year?
      At its rated efficiency it costs about $364-$1,022 a year in electricity in large U.S. cities, depending on climate and local rates - for example $455 in Phoenix and $859 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      What refrigerant does the AUX AM2-H18/2DR3B use?
      It uses R-32.

      Running cost and savings

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

      Heat pump $455/yrYou save $473/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 AUX AM2-H18/2DR3B
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $455
      Current system, per year
      $928
      You save per year
      $473
      Payback
      14.8 years
      Net after 10 years
      -$2,271

      Cooling $272Heating $183Electricity used: 2,845 kWhSaved vs. a minimum-efficiency heat pump: $257

      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 August 11, 2026. How we use the data.