SplitAtlas

Fujitsu / AIRSTAGE Altair 300

Fujitsu AIRSTAGE Altair 300 18k R-32 208/230V Mini-Split

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

The Altair 300 18k is the standout of Fujitsu's entry tier: unlike its smaller siblings it IS ENERGY STAR certified, at SEER2 20 / EER2 11 / HSPF2 9 on R-32, with a strong 14,500 BTU of heat at 5F. It is the value-tier pick that still qualifies for efficiency programs.

1 zoneProfessional installCurrent

Refrigerant generation

R-32 - current-generation refrigerant

Error Codes
Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1)

Image: Fujitsu

Data completeness: 100%
Last sourced
Jul 23, 2026

SplitAtlas score

8.2 / 10

Methodology
Cooling efficiencyBottom quartile

(20.0 SEER2) among 18k systems

Heating efficiencyBelow average

(9.0 HSPF2) among 18k systems

Cold-weather performanceBelow average

(80.6% heat retained at 5F; 5 F heating floor) among 18k systems

NoiseTop 10%

(-48 dBA indoor min / 53 dBA outdoor) among 18k systems

WarrantyTop quartile

(12 yr parts / 12 yr compressor) across the catalogue

Documentation & partsTop quartile

(9 manuals; spec sheet; parts channel) 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

    quote-only - no retail price to evaluate

Key ratings

Rated cooling

18,000BTU/h[3]

Rated heating

18,000BTU/h[3]

Best-fit use cases

A large living room or open area for a value-focused buyer who wants an ENERGY-STAR-eligible 1.5-ton Fujitsu with respectable cold output, without paying for the higher tiers.

Buyer review snapshot

Install difficulty

Professional install
  • Electrical: 208/230V; MCA 14.7 A; breaker/fuse 15 A.
  • Line set: connection type not sourced; precharged 49 ft; max 82 ft.

Alternatives

Availability and price context

We could not verify a current retail price for this model. We could not find this exact model in stock at a retailer we work with when we last checked on 2026-07-23.

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
Jul 23, 2026
Page reviewed
Jul 23, 2026
Source-backed records
5
Newest source retrieved
Jul 23, 2026

Warranty tiers

Warranty: 5 years parts and 7 years compressor as standard; 12 years parts and compressor if Fujitsu Elite contractor installation and registration.

Review methodology

Strengths

  • ENERGY STAR certified with SEER2 20 - efficiency-program eligible at the value price.
  • Strong low-temperature output for the tier: 14,500 BTU at 5F.
  • 1.5 tons with Fujitsu brand and dealer support.

Weaknesses

  • HSPF2 9 is modest; still the entry line, below the Altair 500/700 and Orion XLTH on seasonal heating.
  • 230V and professional installation required.

Climate suitability

Minimum heating ambient
5 F[1]
Rated heating at 5F
14,500 BTU/h[3]
Rated heating at 17F
12,400 BTU/h[3]
Rated heating at 47F
18,000 BTU/h[3]

Specifications

Show
Manufacturer
Fujitsu
Brand
Fujitsu
Product line
AIRSTAGE Altair 300
Model number
ASUH18KNAS indoor / AOUH18KNAS1 outdoor
Indoor unit model
ASUH18KNAS
Outdoor unit model
AOUH18KNAS1
Number of zones
1
Max indoor units
not published
Rated cooling capacity
18,000 BTU/h[3]
Rated heating capacity
18,000 BTU/h[3]
Voltage
208/230V[1]
MCA
14.7 A[1]
Maximum fuse or breaker size
15 A[1]
Breaker needed
not published
SEER2
20 SEER2[3]
EER2
11 EER2[3]
HSPF2 (Region 4)
9 HSPF2[3]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
3.18 COP[1]
COP at 5F
2.02 COP[3]
Minimum outdoor heating temperature
5 F[1]
Minimum outdoor cooling temperature
50 F[1]
Maximum outdoor temperature
122 F[1]
Indoor noise range
cooling 28-48; heating 30-46 dB(A)[1]
Outdoor noise rating
53 dBA[1]
Indoor weight
23 lb[1]
Outdoor weight
73 lb[1]
Refrigerant
R-32[1]
Refrigerant charge
31 oz[1]
Manufacturer coverage
not published
Line-set size
1/4 in liquid / 1/2 in suction
Included line-set length
Fujitsu publishes factory pre-charge length and flared line sizes; the installer supplies the line set.
Maximum line-set length
82 ft[1]
Max line set per indoor
not published
Maximum elevation difference
66 ft[1]
Max height between indoor units
not published
Wi-Fi support
supported[1]
Energy Star status
ENERGY STAR certified[4]
AHRI certification number
217617837[3]
Warranty
Standard: 5 yr parts / 7 yr compressor (out-of-box residential coverage); Best case: 12 yr parts / 12 yr compressor (Fujitsu Elite contractor installation and registration). 10-year parts and compressor warranty when registered within 60 days for residential installation; 12-year parts and compressor tier when installed by a Fujitsu Elite contractor; 7-year compressor/5-year parts out-of-the-box warranty.
Install path
Professional install
Retail price
We could not find this exact model in stock at a retailer we work with when we last checked on 2026-07-23.
Available retailers
not published
Manual links
AHRI certificate 217617837, AHRI public directory record 217617837, ENERGY STAR record 4497367 for ASUH18KNAS / AOUH18KNAS1, AOUH18KNAS1 installation manual, ASUH18KNAS installation manual, Fujitsu Connect product record AOUH18KNAS1, Fujitsu Connect product record ASUH18KNAS, Fujitsu AIRSTAGE Altair 300 wall-mounted R-32 product page, ASUH18KNAS / AOUH18KNAS1 submittal
Specification sheet
ASUH18KNAS / AOUH18KNAS1 submittal
Last sourced date
Jul 23, 2026

Parts and filters

Fits Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1). Part numbers and fit notes identify compatibility only; no manufacturer endorsement is implied.

remote-control

Fujitsu factory wireless remote controller

Fits
Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1)
Fit note
Fits ASUH18KNAS / AOUH18KNAS1. The submittal states that the wireless remote controller is included but does not publish an orderable replacement part number. Source through Fujitsu support or an authorized dealer with the model and serial number.
Source
Fujitsu AIRSTAGE ASUH09KNAS / AOUH09KNAS1 Submittal, Features, page p. 1 (Wireless remote controller included with the indoor unit)

smart-controller-module

Fujitsu Wi-Fi Adapter, USB type

Fits
Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1)
OEM part number
UTY-TFSXH4
Fit note
Fits ASUH18KNAS / AOUH18KNAS1. Manufacturer documentation publishes this OEM part number for this model family. t255 lookup on 2026-08-12 checked HVACDirect exact/search results, Amazon exact-listing search, public exact-part search, and Fujitsu/GENERAL's online-sales FAQ; no public exact destination with a current price from HVACDirect, Amazon, or a Fujitsu-authorized online parts seller was found. HVACDirect direct fetches were Cloudflare-blocked where exact pages existed, and Fujitsu/GENERAL's own FAQ says public online retail sales are not authorized. Source through an authorized Fujitsu contractor/distributor with the model and serial number.
Source
Fujitsu AIRSTAGE ASUH09KNAS / AOUH09KNAS1 Submittal, ACCESSORIES, page p. 4 (UTY-TFSXH4 Wi-Fi Adapter (WiFi Interface Module USB Type))

ir-wifi-controller

Fujitsu Intesis IR Wireless AC Cloud Control Interface

Fits
Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1)
OEM part number
FJ-IR-WIFI-1NA
Fit note
Fits ASUH18KNAS / AOUH18KNAS1. Manufacturer documentation publishes this OEM part number for this model family. t255 lookup on 2026-08-12 checked HVACDirect exact/search results, Amazon exact-listing search, public exact-part search, and Fujitsu/GENERAL's online-sales FAQ; no public exact destination with a current price from HVACDirect, Amazon, or a Fujitsu-authorized online parts seller was found. HVACDirect direct fetches were Cloudflare-blocked where exact pages existed, and Fujitsu/GENERAL's own FAQ says public online retail sales are not authorized. Source through an authorized Fujitsu contractor/distributor with the model and serial number.
Source
Fujitsu AIRSTAGE ASUH09KNAS / AOUH09KNAS1 Submittal, ACCESSORIES, page p. 4 (FJ-IR-WIFI-1NA Intesis IR Wireless AC Cloud Control Interface (Intesis Home app))
Replacement Parts & Filters

Electrical requirements

Show
Voltage
not published
Voltage range
208/230V[1]
Phase
single-phase[2]
Frequency
60 Hz[1]
MCA
14.7 A[1]
Breaker needed
not published
Maximum breaker size
15 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
49 ft[1]
Included line-set length
Fujitsu publishes factory pre-charge length and flared line sizes; the installer supplies the line set.
Maximum line-set length
82 ft[1]
Max line set per indoor
not published
Max height between indoor units
not published
Indoor dimensions
10-5/8 x 32-13/16 x 9-7/16 in[1]
Outdoor dimensions
21-5/16 x 31-7/16 x 11-7/16 in[1]
Indoor weight
23 lb[1]
Outdoor weight
73 lb[1]
Drain size
17/32 in I.D.; 5/8 to 21/32 in O.D.[1]

Related systems and guides

Frequently asked questions

Can I install the Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1) myself, or do I need a pro?
Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1) 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 Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1) keep heating in a cold winter?
The manufacturer publishes 14,500 BTU/h of heating output at 5F. Rated heating operation extends down to 5 F. Certified heating efficiency is 9 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 Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1) need?
Published electrical requirements: 208/230V voltage, 14.7 A minimum circuit ampacity, and 15 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 82 ft, and the included line set comes pre-charged for 49 ft. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.
What warranty does the Fujitsu AIRSTAGE Altair 300 18,000 BTU R-32 208/230V (ASUH18KNAS / AOUH18KNAS1) carry?
The manufacturer publishes these warranty tiers: Standard: 5 yr parts / 7 yr compressor (out-of-box residential coverage); Best case: 12 yr parts / 12 yr compressor (Fujitsu Elite contractor installation and registration). Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.

Data sources

Show
  1. Fujitsu General America, Inc.: ASUH18KNAS & AOUH18KNAS1 submittalSourced - manufacturer technical document

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

  2. Fujitsu General America, Inc.: AOUH18KNAS1 installation manualSourced - manufacturer technical document

    Covers Phase

  3. AHRI Directory: AHRI public directory record 217617837Sourced - AHRI directory

    Covers AHRI certification number, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity, HSPF2 (Region 4) and more

  4. ENERGY STAR: ENERGY STAR certified mini-split row 4497367 for ASUH18KNAS / AOUH18KNAS1Sourced - Energy Star listing

    Covers Energy Star status

  5. Fujitsu General America, Inc.: Fujitsu AIRSTAGE Altair 300 wall-mounted R-32 product pageSourced - manufacturer product page

    Covers Best-case compressor warranty, Best-case warranty conditions, Best-case parts warranty, Legacy compressor warranty value, Legacy warranty value, Standard compressor warranty and more

Last updated

Jul 23, 2026