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      18,000 BTU mini-split heat pump · Charmo

      GREE GWH18ATDXE-D6DNA1C/O

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

      Ranks #290 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $525 a year to run in a mixed climate like Atlanta.

      SEER2
      21.5 Cooling efficiency over a season
      Below average · beats 39%
      HSPF2
      8.5 Heating efficiency over a season
      Below average · beats 2%
      EER2
      11.8 Cooling efficiency on a 95°F day
      Below average · beats 18%
      Heat at 5°F
      13,000 BTU/h70% of its 47°F output
      Below average · beats 27%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 13,000 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

      Specifications18,000 BTU, R-32
      General
      BrandGREE
      Outdoor unit modelGWH18ATDXE-D6DNA1C/O
      SeriesCharmo
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceDecember 12, 2024
      Last certifiedMarch 17, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better21.5 (range 21.5)
      EER2Efficiency at 95°F outdoors11.8
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.5
      Capacity at 47°F18,500 BTU/h
      Capacity at 17°F15,000 BTU/h
      Capacity at 5°F13,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.90
      ENERGY STAR cold climateYes
      Heating output as it gets colder70% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with GWH18ATDXE-D6DN***/I 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.
      GWH18ATDXE-D6DN***/I · cold climate21.511.88.513,000214608823
      GWH18AWDXE-D6DN***/I · cold climate21.511.88.513,000214608824
      GWH18AYDXE-D6DN***/I · cold climate21.511.88.513,000215887358
      Yearly running cost in 10 large cities$397-$1,313

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

      Questions5
      What is the SEER2 rating of the GREE GWH18ATDXE-D6DNA1C/O?
      The GREE GWH18ATDXE-D6DNA1C/O is rated at up to 21.5 SEER2 and 11.8 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 GREE GWH18ATDXE-D6DNA1C/O good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,000 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 GREE GWH18ATDXE-D6DNA1C/O cost to run per year?
      At its rated efficiency it costs about $397-$1,313 a year in electricity in large U.S. cities, depending on climate and local rates - for example $525 in Phoenix and $1,124 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 GREE GWH18ATDXE-D6DNA1C/O?
      ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use GWH18ATDXE-D6DN***/I, GWH18AWDXE-D6DN***/I, GWH18AYDXE-D6DN***/I.
      What refrigerant does the GREE GWH18ATDXE-D6DNA1C/O 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 $538/yrYou save $398/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 GREE GWH18ATDXE-D6DNA1C/O
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $538
      Current system, per year
      $936
      You save per year
      $398
      Payback
      17.6 years
      Net after 10 years
      -$3,022

      Cooling $295Heating $244Electricity used: 3,365 kWhSaved vs. a minimum-efficiency heat pump: $181

      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 17, 2026. How we use the data.