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

      Trane / Mitsubishi Electric NTXSKS18A112

      Average cooling efficiency and very good heating efficiency for a 18,000 BTU mini-split heat pump, but not rated for cold climates.

      Ranks #159 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $450 a year to run in a mixed climate like Atlanta.

      SEER2
      22.9 Cooling efficiency over a season
      Average · beats 58%
      HSPF2
      11.2 Heating efficiency over a season
      Very good · beats 79%
      EER2
      12.5 Cooling efficiency on a 95°F day
      Average · beats 44%
      Heat at 5°F
      10,300 BTU/h52% of its 47°F output
      Excellent · beats 99%

      A good fit if…

      • 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 often see nights below 0°F - it is not cold-climate certified.
      • 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
      BrandTrane / Mitsubishi Electric
      Outdoor unit modelNTXSKS18A112
      SeriesNV-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 sinceDecember 1, 2022
      Last certifiedJanuary 8, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better22.9 (range 22.0-22.9)
      EER2Efficiency at 95°F outdoors12.5-14.1
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.5-11.2
      Capacity at 47°F20,000-21,600 BTU/h
      Capacity at 17°F13,100-14,300 BTU/h
      Capacity at 5°F9,000-10,300 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.50-2.63
      ENERGY STAR cold climateNo
      Heating output as it gets colder52% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with MLZ-KP18NA 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.
      MLZ-KP18NA22.912.510.510,300207699142
      NTXUKS18A11222.912.510.510,300207699143
      PEAD-A18AA922.014.111.29,000213363182
      Yearly running cost in 10 large cities$371-$1,101

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

      Questions5
      What is the SEER2 rating of the Trane / Mitsubishi Electric NTXSKS18A112?
      The Trane / Mitsubishi Electric NTXSKS18A112 is rated at up to 22.9 SEER2 and 12.5 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 3 certified matchups SEER2 ranges from 22.0-22.9.
      Is the Trane / Mitsubishi Electric NTXSKS18A112 good for cold climates?
      It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 18,000 BTU model.
      How much does the Trane / Mitsubishi Electric NTXSKS18A112 cost to run per year?
      At its rated efficiency it costs about $371-$1,101 a year in electricity in large U.S. cities, depending on climate and local rates - for example $473 in Phoenix and $932 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 Trane / Mitsubishi Electric NTXSKS18A112?
      ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use MLZ-KP18NA, NTXUKS18A112, PEAD-A18AA9.
      What refrigerant does the Trane / Mitsubishi Electric NTXSKS18A112 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 $477/yrYou save $484/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 Trane / Mitsubishi Electric NTXSKS18A112
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $477
      Current system, per year
      $961
      You save per year
      $484
      Payback
      14.5 years
      Net after 10 years
      -$2,158

      Cooling $277Heating $200Electricity used: 2,979 kWhSaved vs. a minimum-efficiency heat pump: $265

      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 January 8, 2026. How we use the data.