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      24,000 BTU mini-split heat pump · NV-Series

      Trane / Mitsubishi Electric NTXMMX24A132B

      Below average cooling and heating efficiency for a 24,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #349 of 430 24,000 BTU mini-splits for cooling efficiency, and costs about $652 a year to run in a mixed climate like Atlanta.

      SEER2
      20.0 Cooling efficiency over a season
      Below average · beats 18%
      HSPF2
      9.5 Heating efficiency over a season
      Below average · beats 24%
      EER2
      13.6 Cooling efficiency on a 95°F day
      Very good · beats 75%
      Heat at 5°F
      18,200 BTU/h73% of its 47°F output
      Very good · beats 78%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 18,200 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.
      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications24,000 BTU, R-410A
      General
      BrandTrane / Mitsubishi Electric
      Also sold asAmerican Standard / Mitsubishi Electric
      Outdoor unit modelNTXMMX24A132B
      SeriesNV-Series
      TypeMini-split heat pump
      Nominal size24,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceAugust 1, 2022
      Last certifiedMarch 24, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better20.0 (range 17.5-20.0)
      EER2Efficiency at 95°F outdoors12.2-13.6
      Cooling capacity22,000-22,800 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.7-9.5
      Capacity at 47°F24,400-25,000 BTU/h
      Capacity at 17°F14,600-14,700 BTU/h
      Capacity at 5°F10,800-18,200 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.17-2.20
      ENERGY STAR cold climateYes
      Heating output as it gets colder73% 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 matchups5 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 climate20.013.69.518,200209836190
      - · cold climate20.013.69.518,200212925489
      - American Standard / Mitsubishi Electric · cold climate20.013.69.518,200209843673
      - American Standard / Mitsubishi Electric18.012.28.710,800209999520
      -17.512.28.7-212925504
      Yearly running cost in 10 large cities$520-$1,609

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

      Questions4
      What is the SEER2 rating of the Trane / Mitsubishi Electric NTXMMX24A132B?
      The Trane / Mitsubishi Electric NTXMMX24A132B is rated at up to 20.0 SEER2 and 13.6 EER2 for cooling and up to 9.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 5 certified matchups SEER2 ranges from 17.5-20.0.
      Is the Trane / Mitsubishi Electric NTXMMX24A132B good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 18,200 BTU/h at 5°F with a COP of 2.20, so it is still 2.2 times as efficient as electric resistance heat at that temperature.
      How much does the Trane / Mitsubishi Electric NTXMMX24A132B cost to run per year?
      At its rated efficiency it costs about $520-$1,609 a year in electricity in large U.S. cities, depending on climate and local rates - for example $672 in Phoenix and $1,367 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      What refrigerant does the Trane / Mitsubishi Electric NTXMMX24A132B 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 $682/yrYou save $502/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 NTXMMX24A132B
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $682
      Current system, per year
      $1,183
      You save per year
      $502
      Payback
      16.9 years
      Net after 10 years
      -$3,485

      Cooling $387Heating $295Electricity used: 4,262 kWhSaved vs. a minimum-efficiency heat pump: $233

      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 March 24, 2026. How we use the data.