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      9,000 BTU mini-split heat pump · HS series

      Sea Breeze HSZ9H424ZMO

      Excellent cooling and heating efficiency for a 9,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #104 of 395 9,000 BTU mini-splits for cooling efficiency, and costs about $213 a year to run in a mixed climate like Atlanta.

      SEER2
      26.4 Cooling efficiency over a season
      Excellent · beats 93%
      HSPF2
      12.4 Heating efficiency over a season
      Excellent · beats 93%
      EER2
      15.8 Cooling efficiency on a 95°F day
      Excellent · beats 95%
      Heat at 5°F
      11,000 BTU/h92% of its 47°F output
      Below average · beats 27%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 93% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 11,000 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 93% of mini-splits.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications9,000 BTU, R-410A
      General
      BrandSea Breeze
      Also sold asBreeze33
      Outdoor unit modelHSZ9H424ZMO
      SeriesHS series
      TypeMini-split heat pump
      Nominal size9,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceJanuary 1, 2022
      Last certifiedJune 25, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better26.4 (range 20.2-26.4)
      EER2Efficiency at 95°F outdoors13.0-15.8
      Cooling capacity9,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.6-12.4
      Capacity at 47°F10,000-12,000 BTU/h
      Capacity at 17°F9,300-10,100 BTU/h
      Capacity at 5°F10,500-11,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-1.90
      ENERGY STAR cold climateYes
      Heating output as it gets colder92% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with WM9H424ZMI 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.
      WM9H424ZMI SEA BREEZE+ · cold climate26.415.811.611,000208816889
      SCA9H424ZMI Breeze33 · cold climate24.013.012.410,500211277582
      SCA9H424ZMI SEA BREEZE+ · cold climate24.013.012.410,500212595645
      D9H424ZMI Breeze33 · cold climate20.213.212.010,800211277583
      D9H424ZMI SEA BREEZE+ · cold climate20.213.212.010,800212595646
      Yearly running cost in 10 large cities$162-$531

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

      Questions5
      What is the SEER2 rating of the Sea Breeze HSZ9H424ZMO?
      The Sea Breeze HSZ9H424ZMO is rated at up to 26.4 SEER2 and 15.8 EER2 for cooling and up to 12.4 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 5 certified matchups SEER2 ranges from 20.2-26.4.
      Is the Sea Breeze HSZ9H424ZMO good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,000 BTU/h at 5°F with a COP of 1.90, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the Sea Breeze HSZ9H424ZMO cost to run per year?
      At its rated efficiency it costs about $162-$531 a year in electricity in large U.S. cities, depending on climate and local rates - for example $213 in Phoenix and $454 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 Sea Breeze HSZ9H424ZMO?
      ENERGY STAR lists 5 certified combinations for this outdoor unit. The highest-rated ones use SEA BREEZE+ WM9H424ZMI, Breeze33 SCA9H424ZMI, SEA BREEZE+ SCA9H424ZMI.
      What refrigerant does the Sea Breeze HSZ9H424ZMO use?
      It uses R-410A. R-410A is being phased down under the EPA AIM Act, and new systems are moving to R-454B and 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 $218/yrYou save $277/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 Sea Breeze HSZ9H424ZMO
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $218
      Current system, per year
      $495
      You save per year
      $277
      Payback
      12.6 years
      Net after 10 years
      -$733

      Cooling $120Heating $98Electricity used: 1,365 kWhSaved vs. a minimum-efficiency heat pump: $166

      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 June 25, 2026. How we use the data.