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      18,000 BTU mini-split heat pump · KUSAB181A

      LG KUSAB181A

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

      Ranks #145 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $511 a year to run in a mixed climate like Atlanta.

      SEER2
      23.0 Cooling efficiency over a season
      Average · beats 62%
      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
      15,200 BTU/h70% 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 15,200 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

      Specifications18,000 BTU, R-32
      General
      BrandLG
      Outdoor unit modelKUSAB181A
      SeriesKUSAB181A
      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 23, 2024
      Last certifiedDecember 2, 2025
      Cooling
      SEER2Seasonal efficiency, higher is better23.0 (range 23.0)
      EER2Efficiency at 95°F outdoors13.0
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.0
      Capacity at 47°F21,600 BTU/h
      Capacity at 17°F13,300 BTU/h
      Capacity at 5°F15,200 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80
      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 KNUAB181A 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.
      KNUAB181A · cold climate23.013.010.015,200215413009
      KNUAK181A · cold climate23.013.010.015,200215413010
      Yearly running cost in 10 large cities$372-$1,291

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

      Questions5
      What is the SEER2 rating of the LG KUSAB181A?
      The LG KUSAB181A is rated at up to 23.0 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 LG KUSAB181A good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 15,200 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 LG KUSAB181A cost to run per year?
      At its rated efficiency it costs about $372-$1,291 a year in electricity in large U.S. cities, depending on climate and local rates - for example $500 in Phoenix and $1,110 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 LG KUSAB181A?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use KNUAB181A, KNUAK181A.
      What refrigerant does the LG KUSAB181A 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 $517/yrYou save $470/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 LG KUSAB181A
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $517
      Current system, per year
      $987
      You save per year
      $470
      Payback
      14.9 years
      Net after 10 years
      -$2,304

      Cooling $275Heating $242Electricity used: 3,234 kWhSaved vs. a minimum-efficiency heat pump: $248

      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 December 2, 2025. How we use the data.