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

      Panasonic CU-YM18CBUC

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

      Ranks #72 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $405 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 74%
      Heat at 5°F
      14,200 BTU/h72% of its 47°F output
      Excellent · beats 93%

      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 14,200 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

      Specifications18,000 BTU, R-454B
      General
      BrandPanasonic
      Outdoor unit modelCU-YM18CBUC
      SeriesCU Series
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceDecember 10, 2025
      Last certifiedMay 28, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better24.0 (range 20.0-24.0)
      EER2Efficiency at 95°F outdoors12.5-13.5
      Cooling capacity16,800-18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.1-11.4
      Capacity at 47°F18,000-20,000 BTU/h
      Capacity at 17°F13,900-15,000 BTU/h
      Capacity at 5°F12,800-14,200 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.20-2.40
      ENERGY STAR cold climateYes
      Heating output as it gets colder72% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with CS-YM18CKUW 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.
      CS-YM18CKUW · cold climate24.013.511.113,000218027962
      CS-YM18CB4UW · cold climate20.712.511.412,800218027966
      CS-YM18CD1UW · cold climate20.013.311.314,200218027970
      Yearly running cost in 10 large cities$344-$982

      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-YM18CBUC?
      The Panasonic CU-YM18CBUC 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; across its 3 certified matchups SEER2 ranges from 20.0-24.0.
      Is the Panasonic CU-YM18CBUC good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 14,200 BTU/h at 5°F with a COP of 2.40, so it is still 2.4 times as efficient as electric resistance heat at that temperature.
      How much does the Panasonic CU-YM18CBUC cost to run per year?
      At its rated efficiency it costs about $344-$982 a year in electricity in large U.S. cities, depending on climate and local rates - for example $432 in Phoenix and $827 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-YM18CBUC?
      ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use CS-YM18CKUW, CS-YM18CB4UW, CS-YM18CD1UW.
      What refrigerant does the Panasonic CU-YM18CBUC 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 $434/yrYou save $477/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-YM18CBUC
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $434
      Current system, per year
      $911
      You save per year
      $477
      Payback
      13.6 years
      Net after 10 years
      -$1,730

      Cooling $257Heating $177Electricity used: 2,709 kWhSaved vs. a minimum-efficiency heat pump: $266

      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 May 28, 2026. How we use the data.