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      9,000 BTU mini-split heat pump · C-Series

      AUX AH09MHA3DI-20US

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

      Ranks #363 of 395 9,000 BTU mini-splits for cooling efficiency, and costs about $274 a year to run in a mixed climate like Atlanta.

      SEER2
      20.0 Cooling efficiency over a season
      Below average · beats 18%
      HSPF2
      8.5 Heating efficiency over a season
      Below average · beats 2%
      EER2
      11.4 Cooling efficiency on a 95°F day
      Below average · beats 12%
      Heat at 5°F
      9,000 BTU/h95% 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 9,000 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.
      • You mainly need heat - its HSPF2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications9,000 BTU, R-32
      General
      BrandAUX
      Also sold asSMARTFLEX
      Outdoor unit modelAH09MHA3DI-20US
      SeriesC-Series
      TypeMini-split heat pump
      Nominal size9,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceFebruary 3, 2026
      Last certifiedMarch 24, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better20.0 (range 20.0)
      EER2Efficiency at 95°F outdoors11.4
      Cooling capacity9,100 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.5
      Capacity at 47°F9,500 BTU/h
      Capacity at 17°F7,600 BTU/h
      Capacity at 5°F9,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80
      ENERGY STAR cold climateYes
      Heating output as it gets colder95% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with AWH09MHA3DI-20US 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.
      AWH09MHA3DI-20US · cold climate20.011.48.59,000218080139
      Same unit, other model numbers1

      These model numbers have exactly the same certified ratings and matchups as the AUX AH09MHA3DI-20US: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      Yearly running cost in 10 large cities$215-$680

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

      Questions6
      What is the SEER2 rating of the AUX AH09MHA3DI-20US?
      The AUX AH09MHA3DI-20US is rated at up to 20.0 SEER2 and 11.4 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the AUX AH09MHA3DI-20US good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 9,000 BTU/h at 5°F with a COP of 1.80, so it is still 1.8 times as efficient as electric resistance heat at that temperature.
      How much does the AUX AH09MHA3DI-20US cost to run per year?
      At its rated efficiency it costs about $215-$680 a year in electricity in large U.S. cities, depending on climate and local rates - for example $280 in Phoenix and $579 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the AUX AH09MHA3DI-20US the same as the SMARTFLEX EZI09CN15STG1?
      Yes, as far as the certified ratings go. ENERGY STAR lists both model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.
      Which indoor units work with the AUX AH09MHA3DI-20US?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses AWH09MHA3DI-20US.
      What refrigerant does the AUX AH09MHA3DI-20US 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 $285/yrYou save $190/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 AUX AH09MHA3DI-20US
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $285
      Current system, per year
      $476
      You save per year
      $190
      Payback
      18.4 years
      Net after 10 years
      -$1,596

      Cooling $160Heating $125Electricity used: 1,783 kWhSaved vs. a minimum-efficiency heat pump: $81

      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 March 24, 2026. How we use the data.