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      15,000 BTU mini-split heat pump · MWLD Mini-Split

      Lennox MWLD015S6S-1P

      Average cooling efficiency and very good heating efficiency for a 15,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #15 of 62 15,000 BTU mini-splits for cooling efficiency, and costs about $354 a year to run in a mixed climate like Atlanta.

      SEER2
      23.0 Cooling efficiency over a season
      Average · beats 62%
      HSPF2
      11.0 Heating efficiency over a season
      Very good · beats 75%
      EER2
      14.6 Cooling efficiency on a 95°F day
      Very good · beats 88%
      Heat at 5°F
      15,600 BTU/h104% of its 47°F output
      Excellent · beats 97%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 15,600 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 75% of mini-splits.
      • 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

      Specifications15,000 BTU, R-32
      General
      BrandLennox
      Also sold asSamsung
      Outdoor unit modelMWLD015S6S-1P
      SeriesMWLD Mini-Split
      TypeMini-split heat pump
      Nominal size15,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceJuly 23, 2024
      Last certifiedMarch 26, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better23.0 (range 23.0)
      EER2Efficiency at 95°F outdoors14.6
      Cooling capacity15,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.0
      Capacity at 47°F15,000 BTU/h
      Capacity at 17°F14,000 BTU/h
      Capacity at 5°F15,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.50
      ENERGY STAR cold climateYes
      Heating output as it gets colder104% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with MWMD015S6-1P 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.
      MWMD015S6-1P LENNOX · cold climate23.014.611.015,600216411307
      Same unit, other model numbers3

      These model numbers have exactly the same certified ratings and matchups as the Lennox MWLD015S6S-1P: 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$307-$853

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

      Questions6
      What is the SEER2 rating of the Lennox MWLD015S6S-1P?
      The Lennox MWLD015S6S-1P is rated at up to 23.0 SEER2 and 14.6 EER2 for cooling and up to 11.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Lennox MWLD015S6S-1P good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 15,600 BTU/h at 5°F with a COP of 2.50, so it is still 2.5 times as efficient as electric resistance heat at that temperature.
      How much does the Lennox MWLD015S6S-1P cost to run per year?
      At its rated efficiency it costs about $307-$853 a year in electricity in large U.S. cities, depending on climate and local rates - for example $383 in Phoenix and $716 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the Lennox MWLD015S6S-1P the same as the Lennox MWPD015S6S-1P?
      Yes, as far as the certified ratings go. ENERGY STAR lists 4 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 Lennox MWLD015S6S-1P?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses LENNOX MWMD015S6-1P.
      What refrigerant does the Lennox MWLD015S6S-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 $382/yrYou save $391/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 MWLD015S6S-1P
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $382
      Current system, per year
      $773
      You save per year
      $391
      Payback
      14.1 years
      Net after 10 years
      -$1,589

      Cooling $230Heating $153Electricity used: 2,389 kWhSaved vs. a minimum-efficiency heat pump: $211

      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 26, 2026. How we use the data.