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      48,000 BTU mini-split heat pump · City Multi

      Mitsubishi Electric PUMY-L48NKMU

      Average cooling and heating efficiency for a 48,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #37 of 146 48,000 BTU mini-splits for cooling efficiency, and costs about $1,206 a year to run in a mixed climate like Atlanta.

      SEER2
      23.0 Cooling efficiency over a season
      Average · beats 62%
      HSPF2
      10.4 Heating efficiency over a season
      Average · beats 57%
      EER2
      12.0 Cooling efficiency on a 95°F day
      Below average · beats 25%
      Heat at 5°F
      35,400 BTU/h71% 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 35,400 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • Nothing stands out - its ratings have no weak spot for its class.

      Calculate my running cost

      Details

      Specifications48,000 BTU, R-454B
      General
      BrandMitsubishi Electric
      Outdoor unit modelPUMY-L48NKMU
      SeriesCity Multi
      TypeMini-split heat pump
      Nominal size48,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceApril 15, 2026
      Last certifiedApril 17, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better23.0 (range 17.0-23.0)
      EER2Efficiency at 95°F outdoors8.4-12.0
      Cooling capacity48,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.5-10.4
      Capacity at 47°F50,000 BTU/h
      Capacity at 17°F31,400-33,400 BTU/h
      Capacity at 5°F35,400 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.96-2.10
      ENERGY STAR cold climateYes
      Heating output as it gets colder71% 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 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.
      - · cold climate23.012.010.435,400216797287
      - · cold climate20.010.210.035,400216797289
      - · cold climate17.08.49.535,400216797288
      Yearly running cost in 10 large cities$986-$2,957

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

      Questions4
      What is the SEER2 rating of the Mitsubishi Electric PUMY-L48NKMU?
      The Mitsubishi Electric PUMY-L48NKMU is rated at up to 23.0 SEER2 and 12.0 EER2 for cooling and up to 10.4 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 3 certified matchups SEER2 ranges from 17.0-23.0.
      Is the Mitsubishi Electric PUMY-L48NKMU good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 35,400 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 Mitsubishi Electric PUMY-L48NKMU cost to run per year?
      At its rated efficiency it costs about $986-$2,957 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,260 in Phoenix and $2,505 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      What refrigerant does the Mitsubishi Electric PUMY-L48NKMU 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 $1,273/yrYou save $1,235/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 PUMY-L48NKMU
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,273
      Current system, per year
      $2,508
      You save per year
      $1,235
      Payback
      14.6 years
      Net after 10 years
      -$5,653

      Cooling $735Heating $538Electricity used: 7,957 kWhSaved vs. a minimum-efficiency heat pump: $655

      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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      See all 146 48,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of April 17, 2026. How we use the data.