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      15,000 BTU mini-split heat pump · M series

      Mitsubishi Electric SUZ-AA18NLHZ

      Below average cooling efficiency and average heating efficiency for a 15,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #61 of 62 15,000 BTU mini-splits for cooling efficiency, and costs about $509 a year to run in a mixed climate like Atlanta.

      SEER2
      17.5 Cooling efficiency over a season
      Below average · beats 3%
      HSPF2
      10.2 Heating efficiency over a season
      Average · beats 53%
      EER2
      11.7 Cooling efficiency on a 95°F day
      Below average · beats 16%
      Heat at 5°F
      20,000 BTU/h100% of its 47°F output
      Average · beats 67%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 20,000 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.
      • You want a choice of indoor units - 12 certified pairings.

      Think twice if…

      • Cooling cost matters most - its SEER2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications15,000 BTU, R-454B
      General
      BrandMitsubishi Electric
      Outdoor unit modelSUZ-AA18NLHZ
      SeriesM series
      TypeMini-split heat pump
      Nominal size15,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceFebruary 3, 2025
      Last certifiedJune 13, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better17.5 (range 16.2-17.5)
      EER2Efficiency at 95°F outdoors11.7-12.8
      Cooling capacity16,400-18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.3-10.2
      Capacity at 47°F18,000-20,000 BTU/h
      Capacity at 17°F12,000-13,400 BTU/h
      Capacity at 5°F18,400-20,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.00-2.10
      ENERGY STAR cold climateYes
      Heating output as it gets colder100% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with MSZ-EX18NLW at the standard test temperatures, in BTU/h:

      Certified matchups12 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.
      MSZ-EX18NLW · cold climate17.511.710.220,000215748482
      MSZ-EX18NLS · cold climate17.511.710.220,000215748479
      MSZ-EX18NLB · cold climate17.511.710.220,000215748477
      MSZ-EX18NL2W · cold climate17.511.710.220,000218597401
      MSZ-EX18NL2S · cold climate17.511.710.220,000218597400
      MSZ-EX18NL2B · cold climate17.511.710.220,000218597399
      SLZ-AF18NL · cold climate17.512.09.320,000215734919
      PEAD-AA18NL · cold climate17.312.710.020,000215734922
      MFZ-KX18NL · cold climate17.212.49.920,000215734921
      MLZ-KX18NL · cold climate17.211.79.518,400215734920
      SEZ-AD18NL · cold climate17.012.810.020,000217232160
      SVZ-AP18NL · cold climate16.212.09.520,000215734923
      Yearly running cost in 10 large cities$441-$1,227

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

      Questions5
      What is the SEER2 rating of the Mitsubishi Electric SUZ-AA18NLHZ?
      The Mitsubishi Electric SUZ-AA18NLHZ is rated at up to 17.5 SEER2 and 11.7 EER2 for cooling and up to 10.2 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 12 certified matchups SEER2 ranges from 16.2-17.5.
      Is the Mitsubishi Electric SUZ-AA18NLHZ good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 20,000 BTU/h at 5°F with a COP of 2.10, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the Mitsubishi Electric SUZ-AA18NLHZ cost to run per year?
      At its rated efficiency it costs about $441-$1,227 a year in electricity in large U.S. cities, depending on climate and local rates - for example $550 in Phoenix and $1,030 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 Mitsubishi Electric SUZ-AA18NLHZ?
      ENERGY STAR lists 12 certified combinations for this outdoor unit. The highest-rated ones use MSZ-EX18NLW, MSZ-EX18NLS, MSZ-EX18NLB.
      What refrigerant does the Mitsubishi Electric SUZ-AA18NLHZ 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 $549/yrYou save $355/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 Mitsubishi Electric SUZ-AA18NLHZ
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $549
      Current system, per year
      $905
      You save per year
      $355
      Payback
      16.9 years
      Net after 10 years
      -$2,450

      Cooling $330Heating $220Electricity used: 3,434 kWhSaved vs. a minimum-efficiency heat pump: $153

      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 13, 2026. How we use the data.