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      1.5-ton central heat pump · AU Series

      AI AIR CONDITIONING AUO18-18N1-M3H

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

      Ranks #64 of 170 1.5 ton central heat pumps for cooling efficiency, and costs about $535 a year to run in a mixed climate like Atlanta.

      SEER2
      18.0 Cooling efficiency over a season
      Average · beats 66%
      HSPF2
      9.3 Heating efficiency over a season
      Average · beats 62%
      EER2
      12.4 Cooling efficiency on a 95°F day
      Very good · beats 76%
      Heat at 5°F
      16,500 BTU/h87% of its 47°F output
      Average · beats 48%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 16,500 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications1.5 ton, R-410A
      General
      BrandAI AIR CONDITIONING
      Also sold asMitsutomo, PerfectAire, ECO AC, Grandaire
      Outdoor unit modelAUO18-18N1-M3H
      SeriesAU Series
      TypeCentral heat pump
      Nominal size1.5 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceMay 20, 2024
      Last certifiedJune 9, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better18.0 (range 18.0)
      EER2Efficiency at 95°F outdoors12.4
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.3
      Capacity at 47°F19,000 BTU/h
      Capacity at 17°F13,500 BTU/h
      Capacity at 5°F16,500 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.04
      ENERGY STAR cold climateYes
      Heating output as it gets colder87% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with AUH2-18N1-BM3E at the standard test temperatures, in BTU/h:

      Certified matchups1 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.
      AUH2-18N1-BM3E · cold climate18.012.49.316,500213769922
      Same unit, other model numbers4

      These model numbers have exactly the same certified ratings and matchups as the AI AIR CONDITIONING AUO18-18N1-M3H: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      Yearly running cost in 10 large cities$470-$1,284

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

      Questions6
      What is the SEER2 rating of the AI AIR CONDITIONING AUO18-18N1-M3H?
      The AI AIR CONDITIONING AUO18-18N1-M3H is rated at up to 18.0 SEER2 and 12.4 EER2 for cooling and up to 9.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the AI AIR CONDITIONING AUO18-18N1-M3H good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 16,500 BTU/h at 5°F with a COP of 2.04, so it is still 2.0 times as efficient as electric resistance heat at that temperature.
      How much does the AI AIR CONDITIONING AUO18-18N1-M3H cost to run per year?
      At its rated efficiency it costs about $470-$1,284 a year in electricity in large U.S. cities, depending on climate and local rates - for example $583 in Phoenix and $1,076 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the AI AIR CONDITIONING AUO18-18N1-M3H the same as the Mitsutomo UHO18-NB-Q?
      Yes, as far as the certified ratings go. ENERGY STAR lists 5 model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.
      Which indoor units work with the AI AIR CONDITIONING AUO18-18N1-M3H?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses AUH2-18N1-BM3E.
      What refrigerant does the AI AIR CONDITIONING AUO18-18N1-M3H 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 $581/yrYou save $364/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 AI AIR CONDITIONING AUO18-18N1-M3H
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $581
      Current system, per year
      $944
      You save per year
      $364
      Payback
      19.2 years
      Net after 10 years
      -$3,363

      Cooling $352Heating $229Electricity used: 3,630 kWhSaved vs. a minimum-efficiency heat pump: $146

      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 9, 2026. How we use the data.