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      9,000 BTU mini-split heat pump · WindFree - Max heat (RAC)

      Lennox MWMD009S6-1P

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

      Ranks #175 of 395 9,000 BTU mini-splits for cooling efficiency, and costs about $244 a year to run in a mixed climate like Atlanta.

      SEER2
      25.0 Cooling efficiency over a season
      Very good · beats 83%
      HSPF2
      10.5 Heating efficiency over a season
      Average · beats 61%
      EER2
      16.4 Cooling efficiency on a 95°F day
      Excellent · beats 98%
      Heat at 5°F
      8,500 BTU/h77% of its 47°F output
      Very good · beats 76%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 83% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 8,500 BTU/h at 5°F.
      • 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

      Specifications9,000 BTU, R-32
      General
      BrandLennox
      Outdoor unit modelMWMD009S6-1P
      SeriesWindFree - Max heat (RAC)
      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 sinceJuly 5, 2024
      Last certifiedApril 17, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better25.0 (range 25.0)
      EER2Efficiency at 95°F outdoors16.4
      Cooling capacity9,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.5
      Capacity at 47°F11,000 BTU/h
      Capacity at 17°F9,900 BTU/h
      Capacity at 5°F8,500 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.19
      ENERGY STAR cold climateYes
      Heating output as it gets colder77% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with MWLD009S6S-1P at the standard test temperatures, in BTU/h:

      Certified matchups2 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.
      MWLD009S6S-1P LENNOX · cold climate25.016.410.58,500215810007
      MWPD009S6S-1P LENNOX · cold climate25.016.410.58,500215810012
      Yearly running cost in 10 large cities$172-$622

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

      Questions5
      What is the SEER2 rating of the Lennox MWMD009S6-1P?
      The Lennox MWMD009S6-1P is rated at up to 25.0 SEER2 and 16.4 EER2 for cooling and up to 10.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Lennox MWMD009S6-1P good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 8,500 BTU/h at 5°F with a COP of 2.19, so it is still 2.2 times as efficient as electric resistance heat at that temperature.
      How much does the Lennox MWMD009S6-1P cost to run per year?
      At its rated efficiency it costs about $172-$622 a year in electricity in large U.S. cities, depending on climate and local rates - for example $234 in Phoenix and $537 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 Lennox MWMD009S6-1P?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use LENNOX MWLD009S6S-1P, LENNOX MWPD009S6S-1P.
      What refrigerant does the Lennox MWMD009S6-1P 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 $244/yrYou save $253/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 Lennox MWMD009S6-1P
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $244
      Current system, per year
      $497
      You save per year
      $253
      Payback
      13.8 years
      Net after 10 years
      -$973

      Cooling $127Heating $117Electricity used: 1,525 kWhSaved vs. a minimum-efficiency heat pump: $142

      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 9,000 BTU models

      See all 395 9,000 BTU mini-splits, ranked

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