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

      AUX ASW-H18E3C2/*R3DI-C3

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

      Ranks #234 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $474 a year to run in a mixed climate like Atlanta.

      SEER2
      22.0 Cooling efficiency over a season
      Average · beats 48%
      HSPF2
      9.5 Heating efficiency over a season
      Below average · beats 24%
      EER2
      12.0 Cooling efficiency on a 95°F day
      Below average · beats 25%
      Heat at 5°F
      13,500 BTU/h75% of its 47°F output
      Very good · beats 78%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 13,500 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You mainly need heat - its HSPF2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications18,000 BTU, R-32
      General
      BrandAUX
      Also sold asAUFIT
      Outdoor unit modelASW-H18E3C2/*R3DI-C3
      SeriesM-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 sinceJanuary 5, 2026
      Last certifiedJune 25, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better22.0 (range 22.0)
      EER2Efficiency at 95°F outdoors12.0
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.5
      Capacity at 47°F18,000 BTU/h
      Capacity at 17°F15,000 BTU/h
      Capacity at 5°F13,500 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.20
      ENERGY STAR cold climateYes
      Heating output as it gets colder75% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with ASW-H18E3C2/*R3DI-C3 at the standard test temperatures, in BTU/h:

      Certified matchups2 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.
      ASW-H18E3C2/*R3DI-C3 · cold climate22.012.09.513,500215405088
      ASW-H18E3C2/*R3DI-C3 AUFIT · cold climate22.012.09.513,500217902883
      Yearly running cost in 10 large cities$387-$1,164

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

      Questions5
      What is the SEER2 rating of the AUX ASW-H18E3C2/*R3DI-C3?
      The AUX ASW-H18E3C2/*R3DI-C3 is rated at up to 22.0 SEER2 and 12.0 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 AUX ASW-H18E3C2/*R3DI-C3 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 2.20, so it is still 2.2 times as efficient as electric resistance heat at that temperature.
      How much does the AUX ASW-H18E3C2/*R3DI-C3 cost to run per year?
      At its rated efficiency it costs about $387-$1,164 a year in electricity in large U.S. cities, depending on climate and local rates - for example $495 in Phoenix and $987 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 AUX ASW-H18E3C2/*R3DI-C3?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use ASW-H18E3C2/*R3DI-C3, AUFIT ASW-H18E3C2/*R3DI-C3.
      What refrigerant does the AUX ASW-H18E3C2/*R3DI-C3 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 $500/yrYou save $428/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 ASW-H18E3C2/*R3DI-C3
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $500
      Current system, per year
      $928
      You save per year
      $428
      Payback
      16.4 years
      Net after 10 years
      -$2,721

      Cooling $288Heating $212Electricity used: 3,126 kWhSaved vs. a minimum-efficiency heat pump: $212

      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 June 25, 2026. How we use the data.