SplitAtlas

Fujitsu / AIRSTAGE H-series

Fujitsu AIRSTAGE H-series 18k Compact Cassette R-32 208/230V Mini-Split

Certified capacity
18,000 BTU/h[2]
SEER2
21.9 SEER2[2]
Heating floor
-5 F[3]
Voltage
208/230V[1]
Install path
Professional install

The Fujitsu AIRSTAGE H-series Compact Cassette 18k pairs ACUH18KUAS with AOUH18KUAS1 for a professional, dealer-quoted compact ceiling cassette installation instead of a wall head. It certifies at 18,000 BTU cooling and 21,600 BTU heating at 47F, with 21.9 SEER2, 12.6 EER2, and 11.3 HSPF2. Its certified 5F output is 17,100 BTU, matching or beating the 17F rating, so it is a serious cold-weather candidate.

1 zoneProfessional installCurrent

Refrigerant generation

R-32 - current-generation refrigerant

This brand doesn't honor its warranty on systems bought online. Buy it through a local contractor who installs it: get quotes from installers in your area, and ask whether they're an authorized dealer for this brand.

Get installation quotes
Error Codes
Data completeness: 100%
Last sourced
Aug 5, 2026

SplitAtlas score

8.7 / 10

Methodology
Cooling efficiencyAbove average

(21.9 SEER2) among 18k systems

Heating efficiencyTop quartile

(11.3 HSPF2) among 18k systems

Cold-weather performanceBelow average

(5F certified capacity: 79.2% of the 47F rating; -5 F heating floor) among 18k systems

NoiseBelow average

(29 dBA indoor min / 55 dBA outdoor) among 18k systems

Documentation & partsTop quartile

(3 manuals; spec sheet; 36 error-code rows) across the catalogue

Not evaluated

  • Installation accessibility — not applicable (professional install)N/A

    professional install - DIY-accessibility not applicable

  • Price-to-value — not evaluatedN/A

    This is a professionally installed, quote-only system, so we can't score its price. Get an installed quote to compare real cost.

    Get a quote

Key ratings

Rated cooling

18,000BTU/h[2]

Rated heating

21,600BTU/h[2]

Best-fit use cases

Best for open rooms, offices, and ceiling-grid spaces where a centered cassette is worth the ceiling work around 650-900 sq ft, where the owner wants Fujitsu dealer support and the alternate indoor form is worth the installation work.

Buyer review snapshot

Install difficulty

Professional install
  • Electrical: 208/230V; MCA 14.8 A; breaker/fuse 20 A.
  • Line set: connection type not sourced; precharged 66 ft; max 98 ft.

Alternatives

Availability and price context

Fujitsu sells this system through authorized dealers and contractors, not online, and doesn't honor its warranty on systems bought online. Get installation quotes and ask whether the installer is an authorized Fujitsu dealer.

Purchase channel policy

Fujitsu/GENERAL says online retail sales of its products are not authorized; buyers should treat public online carts as outside the approved purchase channel.

Warranty consequence
Warranty becomes null and void for online purchases.
Authorized channel
Authorized local distributor or contractor channel; password-protected distributor sites are for qualified technicians.

Any online offer for this brand should be treated as a warranty-risk warning, not a recommendation.

Compare online-purchase warranty rules by brand

Source: Fujitsu General America, Inc.: GENERAL AIRSTAGE MINI-SPLITS FAQ - online purchase policy; retrieved Aug 12, 2026.

Source date

Model data sourced
Aug 5, 2026
Page reviewed
Aug 5, 2026
Source-backed records
4
Newest source retrieved
Aug 5, 2026

Review methodology

Model context

Installation context
Ceiling-mounted indoor units need a workable ceiling cavity, panel clearance, drain routing, and service access. Cold-weather output still needs a load calculation and installation clearances, not just the published AHRI rating.

Strengths

  • 18,000 BTU of compact ceiling cassette capacity on current R-32 refrigerant.
  • 21.9 SEER2 / 12.6 EER2 / 11.3 HSPF2 certified efficiency.
  • 14,400 BTU at 17F and 17,100 BTU at 5F give real winter numbers to size against.

Weaknesses

  • At 21.9 SEER2 it gives up 4.4 points to the 18k Circular-Flow Cassette in the same line, so the ceiling format is about distribution and fit rather than the H-Series efficiency peak. It also needs a 20 A circuit where the smallest cassette heads in the H-Series run on 15 A, so the electrical work is not a like-for-like swap.

Climate suitability

Minimum heating ambient
-5 F[3]
Certified heating at 5F
17,100 BTU/h[2]
Rated heating at 17F
14,400 BTU/h[2]
Rated heating at 47F
21,600 BTU/h[2]

Specifications

Show
Manufacturer
Fujitsu
Brand
Fujitsu
Product line
AIRSTAGE H-series
Model number
ACUH18KUAS indoor / AOUH18KUAS1 outdoor
Indoor unit model
ACUH18KUAS
Outdoor unit model
AOUH18KUAS1
Number of zones
1
Max indoor units
not published
Rated cooling capacity
18,000 BTU/h[2]
Rated heating capacity
21,600 BTU/h[2]
Voltage
208/230V[1]
MCA
14.8 A[1]
Maximum fuse or breaker size
20 A[1]
Breaker needed
not published
SEER2
21.9 SEER2[2]
EER2
12.6 EER2[2]
HSPF2 (Region 4)
11.3 HSPF2[2]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
3.54 COP[1]
COP at 5F
2.2 COP[2]
Minimum outdoor heating temperature
-5 F[3]
Minimum outdoor cooling temperature
-5 F[3]
Maximum outdoor temperature
122 F[3]
Indoor noise range
cooling 29-42; heating 30-44 dB(A)[1]
Outdoor noise rating
55 dBA[1]
Indoor weight
35 lb[1]
Outdoor weight
84 lb[1]
Refrigerant
R-32[1]
Refrigerant charge
44 oz[1]
Manufacturer coverage
not published
Line-set size
1/4 in liquid / 1/2 in suction
Included line-set length
Fujitsu publishes pre-charge length and flared line sizes; the installer supplies the line set.
Maximum line-set length
98 ft[1]
Max line set per indoor
not published
Maximum elevation difference
49 ft[1]
Max height between indoor units
not published
Wi-Fi support
supported[1]
Energy Star status
ENERGY STAR certified[2]
AHRI certification number
215434547[2]
Warranty
not published
Install path
Professional install
Retail price
Authorized dealers only
Available retailers
not published
Manual links
Fujitsu ACUH18KUAS installation manual, Fujitsu Connect product record AOUH18KUAS1, Fujitsu AIRSTAGE H-series Compact Cassette submittal - ACUH18KUAS / AOUH18KUAS1
Specification sheet
Fujitsu AIRSTAGE H-series Compact Cassette submittal - ACUH18KUAS / AOUH18KUAS1
Last sourced date
Aug 5, 2026

Electrical requirements

Show
Voltage
not published
Voltage range
208/230V[1]
Phase
single-phase[1]
Frequency
60 Hz[1]
MCA
14.8 A[1]
Breaker needed
not published
Maximum breaker size
20 A[1]
Maximum fuse size
not published
Maximum cooling current
not published
Maximum heating current
not published
Manufacturer wire notes
not published

Installation considerations

Show
Liquid line
1/4 in[1]
Suction line
1/2 in[1]
Line connection type
not published
Precharged length
66 ft[1]
Included line-set length
Fujitsu publishes pre-charge length and flared line sizes; the installer supplies the line set.
Maximum line-set length
98 ft[1]
Max line set per indoor
not published
Max height between indoor units
not published
Indoor dimensions
9-5/8 x 22-7/16 x 22-7/16 in[1]
Outdoor dimensions
24-7/8 x 31-7/16 x 11-7/16 in[1]
Indoor weight
35 lb[1]
Outdoor weight
84 lb[1]
Drain size
not published

Related systems and guides

Frequently asked questions

Can I install the Fujitsu AIRSTAGE H-series Compact Cassette 18,000 BTU R-32 208/230V (ACUH18KUAS / AOUH18KUAS1) myself, or do I need a pro?
Fujitsu AIRSTAGE H-series Compact Cassette 18,000 BTU R-32 208/230V (ACUH18KUAS / AOUH18KUAS1) is built for professional installation: the line set must be flared, evacuated, and charged, which requires EPA-certified refrigerant handling. Installing it outside the manufacturer's requirements can void the warranty, so budget for a qualified HVAC installer.
Will the Fujitsu AIRSTAGE H-series Compact Cassette 18,000 BTU R-32 208/230V (ACUH18KUAS / AOUH18KUAS1) keep heating in a cold winter?
The AHRI/ENERGY STAR certification lists 17,100 BTU/h of heating capacity at 5F. Rated heating operation extends down to -5 F. Certified heating efficiency is 11.3 HSPF2. Match those numbers against your climate's design temperature - in cold regions, output at 5F matters far more than the nameplate capacity measured at 47F.
What electrical circuit does the Fujitsu AIRSTAGE H-series Compact Cassette 18,000 BTU R-32 208/230V (ACUH18KUAS / AOUH18KUAS1) need?
Published electrical requirements: 208/230V voltage, 14.8 A minimum circuit ampacity, and 20 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
How far can the outdoor unit be from the indoor head?
The published maximum line-set length is 98 ft. The outdoor unit's factory charge covers up to 66 ft of line; longer runs need added refrigerant. Measure the planned routing before ordering.

Data sources

Show
  1. Fujitsu General America, Inc.: Fujitsu AIRSTAGE H-series Compact Cassette submittalSourced - manufacturer technical document

    Covers Frequency, electrical_spec.guaranteed_voltage_range, Maximum breaker size, Minimum circuit ampacity, Phase, Voltage range and more

  2. Air-Conditioning, Heating, and Refrigeration Institute: AHRI Active form-factor row 217895718Sourced - AHRI directory

    Covers AHRI certification number, Rated cooling capacity, COP at 5F, EER2, Energy Star status, Rated heating capacity and more

  3. Fujitsu General America, Inc.: ACUH18KUAS & AOUH18KUAS1 submittalSourced - manufacturer technical document

    Covers Minimum outdoor cooling temperature, Minimum outdoor heating temperature, Maximum outdoor temperature

  4. Fujitsu General America, Inc.: Fujitsu AIRSTAGE warranty pageSourced - manufacturer product page

    Covers Legacy compressor warranty value, Legacy warranty value

Last updated

Aug 5, 2026