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      4-ton central heat pump · CU Series

      Panasonic CU-HM55BAHU

      Average cooling and heating efficiency for a 4-ton central heat pump, and certified for cold climates.

      Ranks #157 of 319 4 ton central heat pumps for cooling efficiency, and costs about $1,650 a year to run in a mixed climate like Atlanta.

      SEER2
      17.1 Cooling efficiency over a season
      Average · beats 53%
      HSPF2
      9.0 Heating efficiency over a season
      Average · beats 54%
      EER2
      10.3 Cooling efficiency on a 95°F day
      Below average · beats 16%
      Heat at 5°F
      52,000 BTU/h71% 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 52,000 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

      Specifications4 ton, R-454B
      General
      BrandPanasonic
      Outdoor unit modelCU-HM55BAHU
      SeriesCU Series
      TypeCentral heat pump
      Nominal size4 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceNovember 30, 2024
      Last certifiedJanuary 20, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better17.1 (range 15.2-17.1)
      EER2Efficiency at 95°F outdoors10.0-10.3
      Cooling capacity47,000-54,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.1-9.0
      Capacity at 47°F56,000-58,000 BTU/h
      Capacity at 17°F36,000-45,000 BTU/h
      Capacity at 5°F40,000-52,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-1.83
      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 matchup with CS-HM60BAMU3 at the standard test temperatures, in BTU/h:

      Certified matchups8 indoor units

      The same outdoor unit scores differently with each indoor unit and furnace. Ask your installer for the AHRI reference number of the exact system you are quoted.

      Indoor unitFurnaceSEER2EER2HSPF2Heat @5°FAHRI ref.
      CS-HM60BAMU3 · cold climateS9V2C100U5VS***17.110.38.440,000217900510
      CS-HM60BAMU3 · cold climateS9V2C100D5VS***17.110.38.440,000217900509
      CS-HM60BAMU3 · cold climateS9V2C080U5VS***17.010.28.340,000217900508
      CS-HM60BAAU4 · cold climateS9V2D120D5VS***16.410.28.741,000217900514
      CS-HM60BAAU4 · cold climateS9V2D120U5VS***16.410.28.741,000217900515
      CS-HM60BAHU · cold climate-16.010.09.052,000216505884
      CS-HM60BAMU3 · cold climate-16.010.08.545,000216980456
      CS-HM60BAAU4 · cold climate-15.210.08.143,000216621503
      Yearly running cost in 10 large cities$1,484-$3,938

      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-HM55BAHU?
      The Panasonic CU-HM55BAHU is rated at up to 17.1 SEER2 and 10.3 EER2 for cooling and up to 9.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 8 certified matchups SEER2 ranges from 15.2-17.1.
      Is the Panasonic CU-HM55BAHU good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 52,000 BTU/h at 5°F with a COP of 1.83, so it is still 1.8 times as efficient as electric resistance heat at that temperature.
      How much does the Panasonic CU-HM55BAHU cost to run per year?
      At its rated efficiency it costs about $1,484-$3,938 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,825 in Phoenix and $3,287 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-HM55BAHU?
      ENERGY STAR lists 8 certified combinations for this outdoor unit. The highest-rated ones use CS-HM60BAMU3, CS-HM60BAAU4, CS-HM60BAHU.
      What refrigerant does the Panasonic CU-HM55BAHU 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 $1,808/yrYou save $1,009/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-HM55BAHU
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,808
      Current system, per year
      $2,817
      You save per year
      $1,009
      Payback
      20.3 years
      Net after 10 years
      -$10,414

      Cooling $1,112Heating $697Electricity used: 11,303 kWhSaved vs. a minimum-efficiency heat pump: $357

      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 January 20, 2026. How we use the data.