HVAC Rated
    Menu

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

      Mitsutomo HO-SZ18-AB-Q

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

      Ranks #200 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $418 a year to run in a mixed climate like Atlanta.

      SEER2
      22.0 Cooling efficiency over a season
      Average · beats 48%
      HSPF2
      11.2 Heating efficiency over a season
      Very good · beats 79%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Average · beats 62%
      Heat at 5°F
      17,700 BTU/h96% of its 47°F output
      Average · beats 48%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 17,700 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 79% of mini-splits.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications18,000 BTU, R-410A
      General
      BrandMitsutomo
      Outdoor unit modelHO-SZ18-AB-Q
      SeriesHO Series
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceMay 20, 2024
      Last certifiedJune 13, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better22.0 (range 17.6-22.0)
      EER2Efficiency at 95°F outdoors11.0-13.0
      Cooling capacity16,000-18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.9-11.2
      Capacity at 47°F17,000-20,000 BTU/h
      Capacity at 17°F11,100-15,600 BTU/h
      Capacity at 5°F16,000-17,700 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.75-2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder96% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with HW-SZ18-AB-Q at the standard test temperatures, in BTU/h:

      Certified matchups7 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.
      HW-SZ18-AB-Q · cold climate22.013.010.617,200211306395
      HF-UZ18-AB-Q · cold climate20.512.59.816,800214056572
      HL-UZ16-AB-Q · cold climate20.211.08.916,700214056571
      HC-UZ18-AB-Q · cold climate20.012.59.516,000214056564
      HJ-UZ18-AB-Q · cold climate19.812.511.216,700211306400
      HD-UZ18-AB-Q · cold climate18.011.79.517,700214056568
      HV-UZ18-AB-Q · cold climate17.611.79.617,000214056582
      Yearly running cost in 10 large cities$364-$1,007

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

      Questions5
      What is the SEER2 rating of the Mitsutomo HO-SZ18-AB-Q?
      The Mitsutomo HO-SZ18-AB-Q is rated at up to 22.0 SEER2 and 13.0 EER2 for cooling and up to 11.2 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 7 certified matchups SEER2 ranges from 17.6-22.0.
      Is the Mitsutomo HO-SZ18-AB-Q good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 17,700 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.
      How much does the Mitsutomo HO-SZ18-AB-Q cost to run per year?
      At its rated efficiency it costs about $364-$1,007 a year in electricity in large U.S. cities, depending on climate and local rates - for example $453 in Phoenix and $845 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 Mitsutomo HO-SZ18-AB-Q?
      ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use HW-SZ18-AB-Q, HF-UZ18-AB-Q, HL-UZ16-AB-Q.
      What refrigerant does the Mitsutomo HO-SZ18-AB-Q use?
      It uses R-410A. R-410A is being phased down under the EPA AIM Act, and new systems are moving to R-454B and 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 $452/yrYou save $441/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 Mitsutomo HO-SZ18-AB-Q
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $452
      Current system, per year
      $893
      You save per year
      $441
      Payback
      14.7 years
      Net after 10 years
      -$2,091

      Cooling $272Heating $180Electricity used: 2,825 kWhSaved vs. a minimum-efficiency heat pump: $235

      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.

      Similar 18,000 BTU models

      See all 465 18,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 13, 2026. How we use the data.