HVAC Rated
    Menu

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

      American Standard / Mitsubishi Electric NAXSPH18B112A

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

      Ranks #314 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $455 a year to run in a mixed climate like Atlanta.

      SEER2
      21.0 Cooling efficiency over a season
      Below average · beats 30%
      HSPF2
      10.7 Heating efficiency over a season
      Average · beats 68%
      EER2
      12.5 Cooling efficiency on a 95°F day
      Average · beats 44%
      Heat at 5°F
      22,400 BTU/h118% 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 22,400 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

      Specifications18,000 BTU, R-410A
      General
      BrandAmerican Standard / Mitsubishi Electric
      Outdoor unit modelNAXSPH18B112A
      SeriesM-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 certifiedMarch 13, 2025
      Cooling
      SEER2Seasonal efficiency, higher is better21.0 (range 21.0)
      EER2Efficiency at 95°F outdoors12.5
      Cooling capacity17,200 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.7
      Capacity at 47°F19,000 BTU/h
      Capacity at 17°F12,800 BTU/h
      Capacity at 5°F22,400 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder118% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with NAXWPH18B112AA 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.
      NAXWPH18B112AA · cold climate21.012.510.722,400206195823
      Yearly running cost in 10 large cities$386-$1,104

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

      Questions5
      What is the SEER2 rating of the American Standard / Mitsubishi Electric NAXSPH18B112A?
      The American Standard / Mitsubishi Electric NAXSPH18B112A is rated at up to 21.0 SEER2 and 12.5 EER2 for cooling and up to 10.7 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the American Standard / Mitsubishi Electric NAXSPH18B112A good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 22,400 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 American Standard / Mitsubishi Electric NAXSPH18B112A cost to run per year?
      At its rated efficiency it costs about $386-$1,104 a year in electricity in large U.S. cities, depending on climate and local rates - for example $486 in Phoenix and $930 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 American Standard / Mitsubishi Electric NAXSPH18B112A?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses NAXWPH18B112AA.
      What refrigerant does the American Standard / Mitsubishi Electric NAXSPH18B112A 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 $487/yrYou save $429/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 American Standard / Mitsubishi Electric NAXSPH18B112A
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $487
      Current system, per year
      $916
      You save per year
      $429
      Payback
      15.1 years
      Net after 10 years
      -$2,209

      Cooling $288Heating $199Electricity used: 3,045 kWhSaved vs. a minimum-efficiency heat pump: $220

      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

      See all 465 18,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 13, 2025. How we use the data.