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      24,000 BTU mini-split heat pump · Multi Zone

      Panasonic CU-4Z24BBUC

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

      Ranks #48 of 430 24,000 BTU mini-splits for cooling efficiency, and costs about $661 a year to run in a mixed climate like Atlanta.

      SEER2
      24.0 Cooling efficiency over a season
      Very good · beats 75%
      HSPF2
      11.4 Heating efficiency over a season
      Very good · beats 82%
      EER2
      13.5 Cooling efficiency on a 95°F day
      Very good · beats 72%
      Heat at 5°F
      27,000 BTU/h84% of its 47°F output
      Below average · beats 20%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 75% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 27,000 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 82% of mini-splits.
      • 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

      Specifications24,000 BTU, R-32
      General
      BrandPanasonic
      Outdoor unit modelCU-4Z24BBUC
      SeriesMulti Zone
      TypeMini-split heat pump
      Nominal size24,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceDecember 1, 2024
      Last certifiedApril 17, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better24.0 (range 24.0)
      EER2Efficiency at 95°F outdoors13.5
      Cooling capacity24,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.4
      Capacity at 47°F24,000-32,000 BTU/h
      Capacity at 17°F32,000 BTU/h
      Capacity at 5°F27,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.85
      ENERGY STAR cold climateYes
      Heating output as it gets colder84% 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.
      CS-MXZ5AKUA, CS-MXZ7AKUA, CS-XZ9AKUAW, CS-XZ12AKUAW, CS-XZ15AKUAW, CS-XZ18AKUAW, CS-XZ24AKUAW, CS-Z9AKUAW, CS-Z12AKUAW, CS-Z15AKUAW, CS-Z18AKUAW, CS-Z24AKUAW · cold climate24.013.511.427,000216441721
      - PANASONIC · cold climate24.013.511.427,000216441721
      Yearly running cost in 10 large cities$476-$1,674

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

      Questions5
      What is the SEER2 rating of the Panasonic CU-4Z24BBUC?
      The Panasonic CU-4Z24BBUC is rated at up to 24.0 SEER2 and 13.5 EER2 for cooling and up to 11.4 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Panasonic CU-4Z24BBUC good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 27,000 BTU/h at 5°F with a COP of 1.85, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the Panasonic CU-4Z24BBUC cost to run per year?
      At its rated efficiency it costs about $476-$1,674 a year in electricity in large U.S. cities, depending on climate and local rates - for example $643 in Phoenix and $1,441 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 Panasonic CU-4Z24BBUC?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated one uses CS-MXZ5AKUA, CS-MXZ7AKUA, CS-XZ9AKUAW, CS-XZ12AKUAW, CS-XZ15AKUAW, CS-XZ18AKUAW, CS-XZ24AKUAW, CS-Z9AKUAW, CS-Z12AKUAW, CS-Z15AKUAW, CS-Z18AKUAW, CS-Z24AKUAW.
      What refrigerant does the Panasonic CU-4Z24BBUC use?
      It uses 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 $666/yrYou save $702/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 Panasonic CU-4Z24BBUC
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $666
      Current system, per year
      $1,368
      You save per year
      $702
      Payback
      12.8 years
      Net after 10 years
      -$1,980

      Cooling $352Heating $314Electricity used: 4,165 kWhSaved vs. a minimum-efficiency heat pump: $402

      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 April 17, 2026. How we use the data.