Fujitsu heat pump

AOUH18KUAH1

Mini-split / multi-splitVariable-speed (inverter)ENERGY STAR cold-climateENERGY STAR Most Efficient (some pairings)

The Fujitsu AOUH18KUAH1 is a mini-split / multi-split heat pump outdoor unit with a rated cooling capacity of 18,000 BTU/h (about 1.5 tons) and a variable-speed (inverter) compressor running on R-32 refrigerant. ENERGY STAR lists 6 certified indoor-unit pairings for it. In cold weather it still delivers 24,200 BTU/h at 5°F — 112% of its 47°F output, well above the 76% median across the 308 models we track (better than 99% of them). Its HSPF2 of 11.4 is higher than 94% of models in our database, and its best certified SEER2 of 24.5 beats 93%.

Our take in 30 seconds

Best for: cold and very cold climates

Strengths

  • Keeps 112% of its heat at 5°F, so backup heat rarely runs
  • Heating efficiency (HSPF2 11.4) beats 94% of models
  • Cooling efficiency up to SEER2 24.5, better than 93% of models
  • Variable-speed compressor: quieter, steadier temperatures and better humidity control

Good to know

  • Efficiency depends on the indoor unit: SEER2 ranges 17.5–24.5, so ask which pairing you're quoted
Est. yearly cost
$756
U.S. average rates
SEER2
17.5–24.5
Cooling efficiency
HSPF2
11.4
Top 6% heating efficiency
Heat kept at 5°F
112%
Median is 76%
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Running-cost calculator

Pre-filled with EIA prices · edit any field
Estimated annual cost
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Heating
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Cooling
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Uses the base certified SEER2 (17.5) and HSPF2 (11.4). Assumes the unit is correctly sized. How we calculate.

Heating capacity as it gets colder

A heat pump's output falls as outdoor temperature drops. This is the certified heat output of the Fujitsu AOUH18KUAH1 at the three ENERGY STAR test temperatures (cooling capacity is 18,000 BTU/h for reference).

47°F
21,600 BTU/h
17°F
16,100 BTU/h
5°F
24,200 BTU/h

Retention at 17°F: 75% · at 5°F: 112%. Learn how to use these numbers in our cold-climate guide.

Estimated running cost in every state

Same unit, very different bills: from about $435 a year in Louisiana to $1,714 in Maine, driven by local electricity prices and how much heating or cooling the climate needs. Click a column to sort.

StatePriceHeatingCoolingTotal / yr
Louisiana12.87¢$171$265$435
Florida14.99¢$128$370$498
Mississippi14.43¢$246$267$513
Washington14.63¢$471$53$524
Nevada12.72¢$289$236$525
Tennessee13.42¢$356$179$535
Arizona15.05¢$200$341$540
Oregon15.92¢$483$74$556
North Carolina14.95¢$368$200$568
Kentucky13.80¢$418$156$574
Arkansas14.37¢$354$222$576
South Carolina15.76¢$328$259$588
Georgia15.90¢$331$262$593
Texas15.91¢$271$327$599
Utah13.31¢$479$123$602
Alabama16.33¢$340$269$609
Oklahoma14.82¢$393$229$622
Idaho13.37¢$532$96$628
New Mexico16.51¢$469$170$639
Nebraska13.54¢$539$125$664
West Virginia16.31¢$556$134$690
Missouri16.02¢$516$181$697
Virginia17.64¢$501$200$701
Kansas15.47¢$528$175$703
Wyoming14.43¢$684$74$758
Colorado17.17¢$651$124$774
North Dakota13.31¢$731$62$793
Indiana17.02¢$645$149$794
Delaware18.70¢$602$192$795
Montana15.57¢$738$72$810
California29.75¢$507$306$813
South Dakota15.15¢$718$101$819
Iowa17.06¢$743$132$875
Ohio19.38¢$734$159$894
Maryland21.40¢$689$220$909
Illinois19.32¢$769$159$928
Minnesota17.20¢$880$97$977
Pennsylvania21.77¢$825$179$1,004
Wisconsin19.41¢$919$120$1,039
New Jersey24.61¢$839$228$1,067
District of Columbia25.98¢$788$294$1,082
Connecticut24.51¢$1,022$164$1,186
Michigan22.99¢$1,045$142$1,187
Vermont23.84¢$1,174$110$1,285
Hawaii47.18¢$45$1,262$1,306
Rhode Island28.18¢$1,175$174$1,349
New York28.65¢$1,194$192$1,386
New Hampshire27.64¢$1,309$142$1,451
Massachusetts30.48¢$1,328$188$1,516
Alaska29.41¢$1,672$30$1,702
Maine32.11¢$1,582$132$1,714
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Similar-size alternatives

Other mini-split / multi-split units within ±15% of this model's cooling capacity, sorted by efficiency. Cost difference is versus the Fujitsu AOUH18KUAH1 at U.S.-average rates.

ModelCooling BTU/hSEER2HSPF25°F keptEst. yearly cost
Bryant 37MARAQ18AA318,00020–23.913.571%$610 (−$146)Compare
Bryant 37MAHAQ18AA318,00018–21.512.490%$668 (−$88)Compare
Senville SENA-18HF-OG18,00018–21.412.390%$672 (−$84)Compare
Fujitsu AOUH18KUAS118,00018.6–26.311.482%$744 (−$12)Compare
Fujitsu AOUH18LUAS118,00018.6–23.511.295%$660 (−$96)Compare
Senville SENA/18HF/OQ18,00018–21.511.395%$688 (−$68)Compare

Full specifications

BrandFujitsu
Outdoor modelAOUH18KUAH1
Certified byFujitsu General America, Inc.
Product typeMini-split / multi-split
CompressorVariable-speed (inverter)
RefrigerantR-32
Cooling capacity18,000 BTU/h
Nominal size1.5 tons
SEER2 (certified range)17.5 – 24.5
EER2 (best)13.6
HSPF2 (best)11.4
Heating capacity @ 47°F21,600 BTU/h
Heating capacity @ 17°F16,100 BTU/h
Heating capacity @ 5°F24,200 BTU/h
COP @ 5°F2.3
ENERGY STAR cold-climateYes
Certified indoor pairings6
Latest certification2026-09

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), retrieved November 7, 2026. Capacities and HSPF2 are the highest values across certified pairings; confirm your exact system's AHRI reference number with your installer.

Frequently asked questions

How much does the Fujitsu AOUH18KUAH1 cost to run per year?

At the U.S. average residential electricity price of 18.16¢/kWh and typical national heating and cooling hours, we estimate about $756 per year ($551 heating, $205 cooling). It ranges from about $435 in Louisiana to $1,714 in Maine.

Does the Fujitsu AOUH18KUAH1 work in cold weather?

Yes. It is ENERGY STAR cold-climate certified and delivers 24,200 BTU/h at 5°F, 112% of its 47°F capacity, with a COP of 2.3 at 5°F.

What size is the Fujitsu AOUH18KUAH1?

It is rated at 18,000 BTU/h of cooling, roughly 1.5 tons, and 21,600 BTU/h of heating at 47°F. Proper sizing should be confirmed with a Manual J load calculation.

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