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      36,000 BTU mini-split heat pump · Tosot standard Level Series

      TOSOT TWH36AT19D6DO

      Below average cooling and heating efficiency for a 36,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #130 of 205 36,000 BTU mini-splits for cooling efficiency, and costs about $977 a year to run in a mixed climate like Atlanta.

      SEER2
      21.0 Cooling efficiency over a season
      Below average · beats 30%
      HSPF2
      8.5 Heating efficiency over a season
      Below average · beats 2%
      EER2
      10.6 Cooling efficiency on a 95°F day
      Below average · beats 7%
      Heat at 5°F
      24,600 BTU/h72% of its 47°F output
      Below average · beats 9%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 24,600 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.
      • You mainly need heat - its HSPF2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications36,000 BTU, R-32
      General
      BrandTOSOT
      Outdoor unit modelTWH36AT19D6DO
      SeriesTosot standard Level Series
      TypeMini-split heat pump
      Nominal size36,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceJanuary 17, 2025
      Last certifiedSeptember 23, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better21.0 (range 21.0)
      EER2Efficiency at 95°F outdoors10.6
      Cooling capacity33,600 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.5
      Capacity at 47°F34,000 BTU/h
      Capacity at 17°F22,000 BTU/h
      Capacity at 5°F24,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80
      ENERGY STAR cold climateYes
      Heating output as it gets colder72% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with TWH36AT19D6DI at the standard test temperatures, in BTU/h:

      Certified matchups1 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.
      TWH36AT19D6DI · cold climate21.010.68.524,600216768205
      Yearly running cost in 10 large cities$758-$2,428

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

      Questions5
      What is the SEER2 rating of the TOSOT TWH36AT19D6DO?
      The TOSOT TWH36AT19D6DO is rated at up to 21.0 SEER2 and 10.6 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the TOSOT TWH36AT19D6DO good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 24,600 BTU/h at 5°F with a COP of 1.80, so it is still 1.8 times as efficient as electric resistance heat at that temperature.
      How much does the TOSOT TWH36AT19D6DO cost to run per year?
      At its rated efficiency it costs about $758-$2,428 a year in electricity in large U.S. cities, depending on climate and local rates - for example $990 in Phoenix and $2,071 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 TOSOT TWH36AT19D6DO?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses TWH36AT19D6DI.
      What refrigerant does the TOSOT TWH36AT19D6DO 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 $1,011/yrYou save $728/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 TWH36AT19D6DO
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,011
      Current system, per year
      $1,739
      You save per year
      $728
      Payback
      17.2 years
      Net after 10 years
      -$5,222

      Cooling $563Heating $448Electricity used: 6,320 kWhSaved vs. a minimum-efficiency heat pump: $324

      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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      See all 205 36,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of September 23, 2026. How we use the data.