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      42,000 BTU mini-split heat pump · Multi-Zone Outdoor

      ECO AC EMH-5O42KBB

      Below average cooling efficiency and average heating efficiency for a 42,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #37 of 61 42,000 BTU mini-splits for cooling efficiency, and costs about $1,088 a year to run in a mixed climate like Atlanta.

      SEER2
      21.0 Cooling efficiency over a season
      Below average · beats 30%
      HSPF2
      10.0 Heating efficiency over a season
      Average · beats 43%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Average · beats 62%
      Heat at 5°F
      37,800 BTU/h90% 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 37,800 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • Cooling cost matters most - its SEER2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications42,000 BTU, R-32
      General
      BrandECO AC
      Outdoor unit modelEMH-5O42KBB
      SeriesMulti-Zone Outdoor
      TypeMini-split heat pump
      Nominal size42,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceJanuary 21, 2025
      Last certifiedMarch 17, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better21.0 (range 21.0)
      EER2Efficiency at 95°F outdoors13.0
      Cooling capacity42,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.0
      Capacity at 47°F42,000 BTU/h
      Capacity at 17°F44,500 BTU/h
      Capacity at 5°F37,800 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.10
      ENERGY STAR cold climateYes
      Heating output as it gets colder90% 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 matchups1 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 climate21.013.010.037,800216772343
      Yearly running cost in 10 large cities$942-$2,626

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

      Questions4
      What is the SEER2 rating of the ECO AC EMH-5O42KBB?
      The ECO AC EMH-5O42KBB is rated at up to 21.0 SEER2 and 13.0 EER2 for cooling and up to 10.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the ECO AC EMH-5O42KBB good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 37,800 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 ECO AC EMH-5O42KBB cost to run per year?
      At its rated efficiency it costs about $942-$2,626 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,176 in Phoenix and $2,206 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      What refrigerant does the ECO AC EMH-5O42KBB 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 $1,174/yrYou save $991/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 ECO AC EMH-5O42KBB
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,174
      Current system, per year
      $2,166
      You save per year
      $991
      Payback
      16.1 years
      Net after 10 years
      -$6,088

      Cooling $704Heating $470Electricity used: 7,340 kWhSaved vs. a minimum-efficiency heat pump: $487

      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.

      Similar 42,000 BTU models

      See all 61 42,000 BTU mini-splits, ranked

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