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      18,000 BTU mini-split heat pump · OAH Series

      TRUST AIR CONDITIONERS OAH18H/O6S4P

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

      Ranks #250 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $410 a year to run in a mixed climate like Atlanta.

      SEER2
      21.7 Cooling efficiency over a season
      Average · beats 42%
      HSPF2
      12.3 Heating efficiency over a season
      Excellent · beats 92%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Average · beats 62%
      Heat at 5°F
      18,000 BTU/h100% of its 47°F output
      Average · beats 67%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 18,000 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 92% 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

      Specifications18,000 BTU, R-454B
      General
      BrandTRUST AIR CONDITIONERS
      Outdoor unit modelOAH18H/O6S4P
      SeriesOAH Series
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceAugust 20, 2025
      Last certifiedJuly 29, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better21.7 (range 18.0-21.7)
      EER2Efficiency at 95°F outdoors12.0-13.0
      Cooling capacity16,000-18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.3-12.3
      Capacity at 47°F17,000-20,000 BTU/h
      Capacity at 17°F14,200-16,600 BTU/h
      Capacity at 5°F17,000-18,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.86-2.10
      ENERGY STAR cold climateYes
      Heating output as it gets colder100% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with IUMW118H/I61P at the standard test temperatures, in BTU/h:

      Certified matchups7 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.
      IUMW118H/I61P · cold climate21.713.010.818,000217678068
      IUMC118H/I61P · cold climate20.612.512.217,500217678097
      IUMFC18H/I61P · cold climate20.412.510.317,000217678089
      IUMC418H/I61P · cold climate20.012.512.317,000217678073
      IUMCO18H/I61P · cold climate20.012.510.317,500217678088
      IUMDH18H/I63P · cold climate18.412.011.118,000217678082
      IUMDL18H/I63P · cold climate18.012.010.518,000217678079
      Yearly running cost in 10 large cities$368-$977

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

      Questions5
      What is the SEER2 rating of the TRUST AIR CONDITIONERS OAH18H/O6S4P?
      The TRUST AIR CONDITIONERS OAH18H/O6S4P is rated at up to 21.7 SEER2 and 13.0 EER2 for cooling and up to 12.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 7 certified matchups SEER2 ranges from 18.0-21.7.
      Is the TRUST AIR CONDITIONERS OAH18H/O6S4P good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 18,000 BTU/h at 5°F with a COP of 2.10, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the TRUST AIR CONDITIONERS OAH18H/O6S4P cost to run per year?
      At its rated efficiency it costs about $368-$977 a year in electricity in large U.S. cities, depending on climate and local rates - for example $453 in Phoenix and $816 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 TRUST AIR CONDITIONERS OAH18H/O6S4P?
      ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use IUMW118H/I61P, IUMC118H/I61P, IUMFC18H/I61P.
      What refrigerant does the TRUST AIR CONDITIONERS OAH18H/O6S4P use?
      It uses R-454B.

      Running cost and savings

      Pre-filled with this model. Pick your city and what you heat with today; everything else is optional.

      Heat pump $449/yrYou save $461/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 TRUST AIR CONDITIONERS OAH18H/O6S4P
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $449
      Current system, per year
      $909
      You save per year
      $461
      Payback
      14.1 years
      Net after 10 years
      -$1,895

      Cooling $276Heating $173Electricity used: 2,805 kWhSaved vs. a minimum-efficiency heat pump: $253

      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 July 29, 2026. How we use the data.