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

      Goodman MST183G32MHAA

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

      Ranks #5 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $439 a year to run in a mixed climate like Atlanta.

      SEER2
      27.0 Cooling efficiency over a season
      Excellent · beats 94%
      HSPF2
      11.0 Heating efficiency over a season
      Very good · beats 75%
      EER2
      16.0 Cooling efficiency on a 95°F day
      Excellent · beats 96%
      Heat at 5°F
      20,600 BTU/h100% of its 47°F output
      Average · beats 67%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 94% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 20,600 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
      BrandGoodman
      Also sold asMDV, Franklin
      Outdoor unit modelMST183G32MHAA
      SeriesMST 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 certifiedMay 12, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better27.0 (range 22.0-27.0)
      EER2Efficiency at 95°F outdoors14.5-16.0
      Cooling capacity19,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.0
      Capacity at 47°F20,000 BTU/h
      Capacity at 17°F20,800-21,600 BTU/h
      Capacity at 5°F20,000-20,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.08-2.10
      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 best matchup at the standard test temperatures, in BTU/h:

      Certified matchups3 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.
      - GOODMAN · cold climate27.016.011.020,000218083366
      - GOODMAN · cold climate24.515.011.020,200218083368
      - GOODMAN · cold climate22.014.511.020,600218083367
      Same unit, other model numbers2

      These model numbers have exactly the same certified ratings and matchups as the Goodman MST183G32MHAA: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      Yearly running cost in 10 large cities$334-$1,098

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

      Questions5
      What is the SEER2 rating of the Goodman MST183G32MHAA?
      The Goodman MST183G32MHAA is rated at up to 27.0 SEER2 and 16.0 EER2 for cooling and up to 11.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 3 certified matchups SEER2 ranges from 22.0-27.0.
      Is the Goodman MST183G32MHAA good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 20,600 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 Goodman MST183G32MHAA cost to run per year?
      At its rated efficiency it costs about $334-$1,098 a year in electricity in large U.S. cities, depending on climate and local rates - for example $440 in Phoenix and $939 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the Goodman MST183G32MHAA the same as the MDV M3OD31-18HFN8-M1XD?
      Yes, as far as the certified ratings go. ENERGY STAR lists 3 model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.
      What refrigerant does the Goodman MST183G32MHAA 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 $451/yrYou save $545/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 Goodman MST183G32MHAA
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $451
      Current system, per year
      $996
      You save per year
      $545
      Payback
      12.9 years
      Net after 10 years
      -$1,553

      Cooling $248Heating $204Electricity used: 2,821 kWhSaved vs. a minimum-efficiency heat pump: $315

      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 May 12, 2026. How we use the data.