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

      TOSOT TMSCI7H4R18

      Below average cooling efficiency and average heating efficiency for a 18,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #341 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $466 a year to run in a mixed climate like Atlanta.

      SEER2
      21.0 Cooling efficiency over a season
      Below average · beats 30%
      HSPF2
      10.0 Heating efficiency over a season
      Average · beats 43%
      EER2
      12.0 Cooling efficiency on a 95°F day
      Below average · beats 25%
      Heat at 5°F
      13,800 BTU/h77% 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 13,800 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.

      Calculate my running cost

      Details

      Specifications18,000 BTU, R-32
      General
      BrandTOSOT
      Outdoor unit modelTMSCI7H4R18
      SeriesM-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 sinceJuly 4, 2024
      Last certifiedSeptember 30, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better21.0 (range 16.0-21.0)
      EER2Efficiency at 95°F outdoors11.0-12.0
      Cooling capacity16,000-18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.1-10.0
      Capacity at 47°F18,000 BTU/h
      Capacity at 17°F14,000-15,000 BTU/h
      Capacity at 5°F13,600-13,800 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder77% 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.
      - · cold climate21.012.010.013,800216723136
      - · cold climate19.011.89.013,700216723142
      - · cold climate16.011.08.113,600216723141
      Yearly running cost in 10 large cities$404-$1,125

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

      Questions4
      What is the SEER2 rating of the TOSOT TMSCI7H4R18?
      The TOSOT TMSCI7H4R18 is rated at up to 21.0 SEER2 and 12.0 EER2 for cooling and up to 10.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 3 certified matchups SEER2 ranges from 16.0-21.0.
      Is the TOSOT TMSCI7H4R18 good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,800 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 TOSOT TMSCI7H4R18 cost to run per year?
      At its rated efficiency it costs about $404-$1,125 a year in electricity in large U.S. cities, depending on climate and local rates - for example $504 in Phoenix and $945 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      What refrigerant does the TOSOT TMSCI7H4R18 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 $503/yrYou save $425/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 TOSOT TMSCI7H4R18
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $503
      Current system, per year
      $928
      You save per year
      $425
      Payback
      16.5 years
      Net after 10 years
      -$2,752

      Cooling $302Heating $202Electricity used: 3,146 kWhSaved vs. a minimum-efficiency heat pump: $209

      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

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      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of September 30, 2026. How we use the data.