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      12,000 BTU mini-split heat pump · Lomo

      Airtemp GXH12(3.5)LSK4DH2

      Very good cooling efficiency and below average heating efficiency for a 12,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #193 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $319 a year to run in a mixed climate like Atlanta.

      SEER2
      24.0 Cooling efficiency over a season
      Very good · beats 75%
      HSPF2
      9.0 Heating efficiency over a season
      Below average · beats 10%
      EER2
      12.5 Cooling efficiency on a 95°F day
      Average · beats 44%
      Heat at 5°F
      9,000 BTU/h75% of its 47°F output
      Below average · beats 20%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 75% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 9,000 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You mainly need heat - its HSPF2 is below average for mini-splits.
      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications12,000 BTU, R-410A
      General
      BrandAirtemp
      Also sold asGibson, AireForce
      Outdoor unit modelGXH12(3.5)LSK4DH2
      SeriesLomo
      TypeMini-split heat pump
      Nominal size12,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceJanuary 1, 2023
      Last certifiedJune 23, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better24.0 (range 24.0)
      EER2Efficiency at 95°F outdoors12.5
      Cooling capacity12,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.0
      Capacity at 47°F12,000 BTU/h
      Capacity at 17°F10,000 BTU/h
      Capacity at 5°F9,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.85
      ENERGY STAR cold climateYes
      Heating output as it gets colder75% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with GHH12(3.5)LUK4DH2 at the standard test temperatures, in BTU/h:

      Certified matchups3 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.
      GHH12(3.5)LUK4DH2 AIRTEMP · cold climate24.012.59.09,000210534162
      GHH12(3.5)LUK4DH2 GIBSON · cold climate24.012.59.09,000210534171
      GHH12(3.5)LUK4DH2 AireForce · cold climate24.012.59.09,000211635187
      Yearly running cost in 10 large cities$238-$801

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

      Questions5
      What is the SEER2 rating of the Airtemp GXH12(3.5)LSK4DH2?
      The Airtemp GXH12(3.5)LSK4DH2 is rated at up to 24.0 SEER2 and 12.5 EER2 for cooling and up to 9.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Airtemp GXH12(3.5)LSK4DH2 good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 9,000 BTU/h at 5°F with a COP of 1.85, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the Airtemp GXH12(3.5)LSK4DH2 cost to run per year?
      At its rated efficiency it costs about $238-$801 a year in electricity in large U.S. cities, depending on climate and local rates - for example $316 in Phoenix and $687 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 Airtemp GXH12(3.5)LSK4DH2?
      ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use AIRTEMP GHH12(3.5)LUK4DH2, GIBSON GHH12(3.5)LUK4DH2, AireForce GHH12(3.5)LUK4DH2.
      What refrigerant does the Airtemp GXH12(3.5)LSK4DH2 use?
      It uses R-410A. R-410A is being phased down under the EPA AIM Act, and new systems are moving to R-454B and 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 $325/yrYou save $293/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 Airtemp GXH12(3.5)LSK4DH2
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $325
      Current system, per year
      $619
      You save per year
      $293
      Payback
      15.3 years
      Net after 10 years
      -$1,566

      Cooling $176Heating $149Electricity used: 2,033 kWhSaved vs. a minimum-efficiency heat pump: $149

      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 June 23, 2026. How we use the data.