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      4-ton central heat pump · KUSXB601A

      LG KUSXB601A

      Average cooling and heating efficiency for a 4-ton central heat pump, and certified for cold climates.

      Ranks #146 of 319 4 ton central heat pumps for cooling efficiency, and costs about $1,575 a year to run in a mixed climate like Atlanta.

      SEER2
      17.5 Cooling efficiency over a season
      Average · beats 58%
      HSPF2
      9.4 Heating efficiency over a season
      Average · beats 64%
      EER2
      12.0 Cooling efficiency on a 95°F day
      Average · beats 64%
      Heat at 5°F
      45,000 BTU/h80% of its 47°F output
      Below average · beats 39%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 45,000 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

      Specifications4 ton, R-32
      General
      BrandLG
      Outdoor unit modelKUSXB601A
      SeriesKUSXB601A
      TypeCentral heat pump
      Nominal size4 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceDecember 2, 2024
      Last certifiedApril 22, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better17.5 (range 15.2-17.5)
      EER2Efficiency at 95°F outdoors10.5-12.0
      Cooling capacity45,500-52,500 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.5-9.4
      Capacity at 47°F50,000-56,500 BTU/h
      Capacity at 17°F32,000-36,400 BTU/h
      Capacity at 5°F41,000-45,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder80% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with KNSLB601A at the standard test temperatures, in BTU/h:

      Certified matchups7 indoor units

      The same outdoor unit scores differently with each indoor unit and furnace. Ask your installer for the AHRI reference number of the exact system you are quoted.

      Indoor unitFurnaceSEER2EER2HSPF2Heat @5°FAHRI ref.
      KNSLB601A · cold climate-17.512.09.445,000215588574
      KNSLB601A · cold climate-17.512.09.445,000217284917
      LKMMA60D1 · cold climateLNA**120D117.311.09.443,000217284970
      LKMMA60C1 · cold climateLNA**100C117.011.09.042,000217284969
      LKMMA48C1 · cold climate-15.911.78.941,000216445263
      LKMMA60D1 · cold climate-15.510.79.044,000216445253
      LKMMA60C1 · cold climate-15.210.58.544,000216445252
      Yearly running cost in 10 large cities$1,410-$3,764

      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 KUSXB601A?
      The LG KUSXB601A is rated at up to 17.5 SEER2 and 12.0 EER2 for cooling and up to 9.4 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 7 certified matchups SEER2 ranges from 15.2-17.5.
      Is the LG KUSXB601A good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 45,000 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.
      How much does the LG KUSXB601A cost to run per year?
      At its rated efficiency it costs about $1,410-$3,764 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,737 in Phoenix and $3,144 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 KUSXB601A?
      ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use KNSLB601A, LKMMA60D1, LKMMA60C1.
      What refrigerant does the LG KUSXB601A 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 $1,723/yrYou save $1,041/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 KUSXB601A
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,723
      Current system, per year
      $2,764
      You save per year
      $1,041
      Payback
      18.7 years
      Net after 10 years
      -$9,089

      Cooling $1,056Heating $667Electricity used: 10,770 kWhSaved vs. a minimum-efficiency heat pump: $405

      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 4 ton models

      See all 319 4 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of April 22, 2026. How we use the data.