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      12,000 BTU mini-split heat pump · C-Series

      AUX XH12MAA3DI-20US

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

      Ranks #366 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $357 a year to run in a mixed climate like Atlanta.

      SEER2
      20.0 Cooling efficiency over a season
      Below average · beats 18%
      HSPF2
      8.5 Heating efficiency over a season
      Below average · beats 2%
      EER2
      9.6 Cooling efficiency on a 95°F day
      Below average · beats 4%
      Heat at 5°F
      9,200 BTU/h75% of its 47°F output
      Average · beats 63%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 9,200 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • Cooling cost matters most - its SEER2 is below average for mini-splits.
      • You mainly need heat - its HSPF2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications12,000 BTU, R-32
      General
      BrandAUX
      Also sold asXTRON
      Outdoor unit modelXH12MAA3DI-20US
      SeriesC-Series
      TypeMini-split heat pump
      Nominal size12,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceFebruary 9, 2026
      Last certifiedMarch 24, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better20.0 (range 20.0)
      EER2Efficiency at 95°F outdoors9.6
      Cooling capacity12,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.5
      Capacity at 47°F12,300 BTU/h
      Capacity at 17°F9,000 BTU/h
      Capacity at 5°F9,200 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.09
      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 XWH12MAA3DI-20US 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.
      XWH12MAA3DI-20US · cold climate20.09.68.59,200218083121
      XWH12MAA3DI-20US XTRON · cold climate20.09.68.59,200218156737
      Yearly running cost in 10 large cities$284-$883

      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 XH12MAA3DI-20US?
      The AUX XH12MAA3DI-20US is rated at up to 20.0 SEER2 and 9.6 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the AUX XH12MAA3DI-20US good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 9,200 BTU/h at 5°F with a COP of 2.09, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the AUX XH12MAA3DI-20US cost to run per year?
      At its rated efficiency it costs about $284-$883 a year in electricity in large U.S. cities, depending on climate and local rates - for example $367 in Phoenix and $751 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 XH12MAA3DI-20US?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use XWH12MAA3DI-20US, XTRON XWH12MAA3DI-20US.
      What refrigerant does the AUX XH12MAA3DI-20US 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 $373/yrYou save $250/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 XH12MAA3DI-20US
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $373
      Current system, per year
      $624
      You save per year
      $250
      Payback
      18.0 years
      Net after 10 years
      -$1,996

      Cooling $211Heating $162Electricity used: 2,333 kWhSaved vs. a minimum-efficiency heat pump: $106

      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.