HVAC Rated

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

AI AIR CONDITIONING AO25-18N2-M1H

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

Ranks #244 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
Very good · beats 78%

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
BrandAI AIR CONDITIONING
Also sold asMitsutomo, DuraSTAR
Outdoor unit modelAO25-18N2-M1H
SeriesAO 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 sinceOctober 10, 2024
Last certifiedMay 6, 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 better10.0-12.3
Capacity at 47°F17,000-20,000 BTU/h
Capacity at 17°F14,000-16,600 BTU/h
Capacity at 5°F17,000-18,000 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater1.86-2.20
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 AW25-18N2-M1 at the standard test temperatures, in BTU/h:

Certified matchups8 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.
AW25-18N2-M1 · cold climate21.713.010.818,000215866737
A1C-18N2-M1 · cold climate20.612.512.217,500215866780
AF-18N2-M1 · cold climate20.412.510.317,000215866795
AC-18N2-M1 · cold climate20.012.512.317,000215866773
AS-16N2-M1 · cold climate20.012.510.317,500215866794
AH-18N2-M1 · cold climate18.412.011.118,000215866787
AL-18N2-M1 · cold climate18.012.010.518,000215866784
AAH-18N2-BM1 · cold climate18.012.010.018,000217162311
Same unit, other model numbers2

These model numbers have exactly the same certified ratings and matchups as the AI AIR CONDITIONING AO25-18N2-M1H: 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$368-$977

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 AO25-18N2-M1H?
The AI AIR CONDITIONING AO25-18N2-M1H 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 8 certified matchups SEER2 ranges from 18.0-21.7.
Is the AI AIR CONDITIONING AO25-18N2-M1H 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 2.20, so it is still 2.2 times as efficient as electric resistance heat at that temperature.
How much does the AI AIR CONDITIONING AO25-18N2-M1H 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.
Is the AI AIR CONDITIONING AO25-18N2-M1H the same as the Mitsutomo HO-SZ18-LA-Q?
Yes, as far as the certified ratings go. ENERGY STAR lists 3 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 AO25-18N2-M1H?
ENERGY STAR lists 8 certified combinations for this outdoor unit. The highest-rated ones use AW25-18N2-M1, A1C-18N2-M1, AF-18N2-M1.
What refrigerant does the AI AIR CONDITIONING AO25-18N2-M1H 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 AI AIR CONDITIONING AO25-18N2-M1H
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 May 6, 2026. How we use the data.