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

      Ameristar M4THM1924A13N

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

      Ranks #377 of 430 24,000 BTU mini-splits for cooling efficiency, and costs about $637 a year to run in a mixed climate like Atlanta.

      SEER2
      19.0 Cooling efficiency over a season
      Below average · beats 9%
      HSPF2
      10.0 Heating efficiency over a season
      Average · beats 43%
      EER2
      12.5 Cooling efficiency on a 95°F day
      Average · beats 44%
      Heat at 5°F
      21,600 BTU/h90% of its 47°F output
      Average · beats 67%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 21,600 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 want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications24,000 BTU, R-410A
      General
      BrandAmeristar
      Also sold asRunTru
      Outdoor unit modelM4THM1924A13N
      SeriesN-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 sinceJanuary 1, 2023
      Last certifiedJune 13, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better19.0 (range 19.0)
      EER2Efficiency at 95°F outdoors12.5
      Cooling capacity23,200 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.0
      Capacity at 47°F24,000 BTU/h
      Capacity at 17°F23,600 BTU/h
      Capacity at 5°F21,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.10
      ENERGY STAR cold climateYes
      Heating output as it gets colder90% 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 matchups2 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 climate19.012.510.021,600210488260
      - RUNTRU · cold climate19.012.510.021,600210488275
      Yearly running cost in 10 large cities$574-$1,519

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

      Questions4
      What is the SEER2 rating of the Ameristar M4THM1924A13N?
      The Ameristar M4THM1924A13N is rated at up to 19.0 SEER2 and 12.5 EER2 for cooling and up to 10.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Ameristar M4THM1924A13N good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 21,600 BTU/h at 5°F with a COP of 2.10, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the Ameristar M4THM1924A13N cost to run per year?
      At its rated efficiency it costs about $574-$1,519 a year in electricity in large U.S. cities, depending on climate and local rates - for example $705 in Phoenix and $1,268 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      What refrigerant does the Ameristar M4THM1924A13N 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 $699/yrYou save $511/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 Ameristar M4THM1924A13N
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $699
      Current system, per year
      $1,209
      You save per year
      $511
      Payback
      16.6 years
      Net after 10 years
      -$3,393

      Cooling $430Heating $269Electricity used: 4,366 kWhSaved vs. a minimum-efficiency heat pump: $231

      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 24,000 BTU models

      See all 430 24,000 BTU mini-splits, ranked

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