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      1.5-ton central heat pump · KUSXB181A

      LG KUSXB181A

      Excellent cooling efficiency and very good heating efficiency for a 1.5-ton central heat pump, and certified for cold climates.

      Ranks #2 of 170 1.5 ton central heat pumps for cooling efficiency, and costs about $504 a year to run in a mixed climate like Atlanta.

      SEER2
      20.5 Cooling efficiency over a season
      Excellent · beats 96%
      HSPF2
      10.0 Heating efficiency over a season
      Very good · beats 84%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Very good · beats 89%
      Heat at 5°F
      22,000 BTU/h95% of its 47°F output
      Below average · beats 20%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 96% of central heat pumps.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 22,000 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 84% of central heat pumps.
      • 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

      Specifications1.5 ton, R-32
      General
      BrandLG
      Outdoor unit modelKUSXB181A
      SeriesKUSXB181A
      TypeCentral heat pump
      Nominal size1.5 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceDecember 2, 2024
      Last certifiedSeptember 22, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better20.5 (range 15.2-20.5)
      EER2Efficiency at 95°F outdoors11.5-13.5
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.1-10.0
      Capacity at 47°F19,000-20,000 BTU/h
      Capacity at 17°F12,000-13,000 BTU/h
      Capacity at 5°F14,600-22,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-1.90
      ENERGY STAR cold climateYes
      Heating output as it gets colder95% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with KNUDB181A at the standard test temperatures, in BTU/h:

      Certified matchups9 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.
      KNUDB181A · cold climate-20.513.09.519,000214825953
      KNUFB181A · cold climate-20.512.29.514,600216778957
      KNSLB181A · cold climate-17.513.510.022,000215588571
      KNSLB181A · cold climate-17.513.510.022,000217284911
      KNUJB181A · cold climate-17.512.49.219,000214796352
      LKMMA18A1 · cold climateLNAEA040A117.511.59.018,000217284957
      LKMMA18B1 · cold climateLNA**060B117.011.59.018,000217284958
      LKMMA18B1 · cold climateLNAEA080B117.011.59.018,000218770190
      LKMMA18B1 · cold climate-15.211.78.116,000216445244
      Yearly running cost in 10 large cities$415-$1,233

      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 KUSXB181A?
      The LG KUSXB181A is rated at up to 20.5 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; across its 9 certified matchups SEER2 ranges from 15.2-20.5.
      Is the LG KUSXB181A good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 22,000 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 LG KUSXB181A cost to run per year?
      At its rated efficiency it costs about $415-$1,233 a year in electricity in large U.S. cities, depending on climate and local rates - for example $528 in Phoenix and $1,043 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 KUSXB181A?
      ENERGY STAR lists 9 certified combinations for this outdoor unit. The highest-rated ones use KNUDB181A, KNUFB181A, KNSLB181A.
      What refrigerant does the LG KUSXB181A 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 $533/yrYou save $428/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 KUSXB181A
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $533
      Current system, per year
      $961
      You save per year
      $428
      Payback
      16.4 years
      Net after 10 years
      -$2,722

      Cooling $309Heating $224Electricity used: 3,332 kWhSaved vs. a minimum-efficiency heat pump: $209

      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 1.5 ton models

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