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

      AUX XH18MAA2DI-20US

      Below average cooling and heating efficiency for a 18,000 BTU mini-split heat pump, but not rated for cold climates.

      Ranks #414 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $528 a year to run in a mixed climate like Atlanta.

      SEER2
      20.0 Cooling efficiency over a season
      Below average · beats 18%
      HSPF2
      9.0 Heating efficiency over a season
      Below average · beats 10%
      EER2
      11.0 Cooling efficiency on a 95°F day
      Below average · beats 9%
      Heat at 5°F
      14,200 BTU/h74% of its 47°F output
      Very good · beats 78%

      A good fit if…

      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You often see nights below 0°F - it is not cold-climate certified.
      • 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

      Specifications18,000 BTU, R-32
      General
      BrandAUX
      Also sold asXTRON
      Outdoor unit modelXH18MAA2DI-20US
      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 sinceFebruary 9, 2026
      Last certifiedApril 21, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better20.0 (range 20.0)
      EER2Efficiency at 95°F outdoors11.0
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.0
      Capacity at 47°F19,100 BTU/h
      Capacity at 17°F14,000 BTU/h
      Capacity at 5°F14,200 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.20
      ENERGY STAR cold climateNo
      Heating output as it gets colder74% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with XWH18MAA2DI-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.
      XWH18MAA2DI-20US20.011.09.014,200218083123
      XWH18MAA2DI-20US XTRON20.011.09.014,200218156739
      Yearly running cost in 10 large cities$425-$1,300

      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 XH18MAA2DI-20US?
      The AUX XH18MAA2DI-20US is rated at up to 20.0 SEER2 and 11.0 EER2 for cooling and up to 9.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the AUX XH18MAA2DI-20US good for cold climates?
      It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 18,000 BTU model.
      How much does the AUX XH18MAA2DI-20US cost to run per year?
      At its rated efficiency it costs about $425-$1,300 a year in electricity in large U.S. cities, depending on climate and local rates - for example $547 in Phoenix and $1,104 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 XH18MAA2DI-20US?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use XWH18MAA2DI-20US, XTRON XWH18MAA2DI-20US.
      What refrigerant does the AUX XH18MAA2DI-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 $554/yrYou save $392/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 XH18MAA2DI-20US
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $554
      Current system, per year
      $946
      You save per year
      $392
      Payback
      17.9 years
      Net after 10 years
      -$3,084

      Cooling $317Heating $238Electricity used: 3,466 kWhSaved vs. a minimum-efficiency heat pump: $174

      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 April 21, 2026. How we use the data.