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      42,000 BTU mini-split heat pump · P series

      Mitsubishi Electric PUZ-AK42NLHZ

      Below average cooling and heating efficiency for a 42,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #48 of 61 42,000 BTU mini-splits for cooling efficiency, and costs about $1,384 a year to run in a mixed climate like Atlanta.

      SEER2
      20.0 Cooling efficiency over a season
      Below average · beats 18%
      HSPF2
      9.2 Heating efficiency over a season
      Below average · beats 16%
      EER2
      11.8 Cooling efficiency on a 95°F day
      Below average · beats 18%
      Heat at 5°F
      48,000 BTU/h89% 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 48,000 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

      Specifications42,000 BTU, R-454B
      General
      BrandMitsubishi Electric
      Outdoor unit modelPUZ-AK42NLHZ
      SeriesP series
      TypeMini-split heat pump
      Nominal size42,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceOctober 1, 2024
      Last certifiedMarch 13, 2025
      Cooling
      SEER2Seasonal efficiency, higher is better20.0 (range 17.1-20.0)
      EER2Efficiency at 95°F outdoors10.8-11.8
      Cooling capacity42,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.5-9.2
      Capacity at 47°F54,000 BTU/h
      Capacity at 17°F32,200-38,500 BTU/h
      Capacity at 5°F48,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.75-1.80
      ENERGY STAR cold climateYes
      Heating output as it gets colder89% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with PLA-AE42NL 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.
      PLA-AE42NL · cold climate20.011.89.248,000215712219
      PVA-AA42NL · cold climate18.711.48.748,000215712221
      PEAD-AA42NL · cold climate18.311.08.548,000215712220
      PAA-BA42NL · cold climate17.110.88.748,000215712222
      PAA-CA42NL · cold climate17.110.88.748,000215712223
      Yearly running cost in 10 large cities$1,000-$3,503

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

      Questions5
      What is the SEER2 rating of the Mitsubishi Electric PUZ-AK42NLHZ?
      The Mitsubishi Electric PUZ-AK42NLHZ is rated at up to 20.0 SEER2 and 11.8 EER2 for cooling and up to 9.2 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 5 certified matchups SEER2 ranges from 17.1-20.0.
      Is the Mitsubishi Electric PUZ-AK42NLHZ good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 48,000 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 Mitsubishi Electric PUZ-AK42NLHZ cost to run per year?
      At its rated efficiency it costs about $1,000-$3,503 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,347 in Phoenix and $3,015 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 Mitsubishi Electric PUZ-AK42NLHZ?
      ENERGY STAR lists 5 certified combinations for this outdoor unit. The highest-rated ones use PLA-AE42NL, PVA-AA42NL, PEAD-AA42NL.
      What refrigerant does the Mitsubishi Electric PUZ-AK42NLHZ use?
      It uses R-454B.

      Running cost and savings

      Pre-filled with this model. Pick your city and what you heat with today; everything else is optional.

      Heat pump $1,397/yrYou save $965/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 Mitsubishi Electric PUZ-AK42NLHZ
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,397
      Current system, per year
      $2,362
      You save per year
      $965
      Payback
      16.6 years
      Net after 10 years
      -$6,346

      Cooling $739Heating $657Electricity used: 8,729 kWhSaved vs. a minimum-efficiency heat pump: $444

      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 13, 2025. How we use the data.