Fujitsu AUUH18KUAS & AOUH18KUBS1: 18,000 BTU AIRSTAGE Centauri Circular-Flow Ceiling Cassette Heat Pump System

The Fujitsu AUUH18KUAS paired with the AOUH18KUBS1 outdoor unit offers advanced heating and cooling performance in a high-efficiency 18,000 BTU-class single-zone mini-split system. Part of Fujitsu's AIRSTAGE Centauri series , this sophisticated heat pump system combines a discreet ceiling-mounted circular-flow cassette indoor unit with INVERTER-driven technology for dependable year-round comfort—even in cold outdoor conditions as low as -5°F. Featuring optional Wi-Fi connectivity, advanced airflow distribution, ultra-quiet operation, and environmentally friendly R-32 refrigerant, this system delivers outstanding efficiency, flexible installation, and consistent comfort for residential and light commercial applications.

General Information

System Type: Circular-flow ceiling cassette indoor unit + single-zone heat pump outdoor unit

Models: Indoor – AUUH18KUAS | Outdoor – AOUH18KUBS1

Product Series: Fujitsu AIRSTAGE Centauri

Capacities: 18,000 BTU Rated Cooling (Max 20,100) | 21,600 BTU Rated Heating (Max 25,600)

Operating Modes: Heating & Cooling with automatic operation, economy mode, powerful mode, minimum heat mode, and automatic defrosting

ENERGY STAR®: ENERGY STAR Certified, Cold Climate Certified, and Most Efficient (listed for the original AOUH18KUAS1 pairing)

Refrigerant / Factory Charge: R-32, 2 lb 12 oz (original outdoor unit specification)

AHRI Reference Number: 215434552 (original AOUH18KUAS1 pairing; updated pairing requires verification)

Key Features

Advanced Circular-Flow Cassette Design: Ceiling-mounted cassette distributes conditioned air throughout the room, helping maintain balanced temperatures and consistent comfort while minimizing visible wall-mounted equipment.

Cold-Climate Heating Performance: Designed to provide dependable heating in outdoor temperatures as low as -5°F, making it a practical solution for homes and commercial spaces in colder climates.

Exceptional Heating Capacity: Delivers 21,600 BTU rated heating capacity with a maximum output of 25,600 BTU, providing 20% higher rated heating capacity than its nominal 18,000 BTU classification.

Cold-Weather Heating Capacity: Provides 14,400 BTU rated heating capacity at 17°F, with a maximum output of 19,300 BTU, and delivers 17,100 BTU rated heating capacity at 5°F under manufacturer-specified test conditions.

Advanced INVERTER Technology: Continuously adjusts compressor output to match heating and cooling demands, maximizing efficiency while maintaining consistent indoor temperatures.

Outstanding Energy Efficiency: Achieves an impressive 26.3 SEER2, 13.6 EER2, and 11.4 HSPF2 (Region IV), helping reduce energy consumption and operating costs.

Ultra-Quiet Indoor Operation: Indoor sound levels as low as 28 dB(A) in Quiet Mode provide peaceful comfort for bedrooms, living rooms, offices, and other occupied spaces.

Optional Wi-Fi Connectivity: Compatible with an optional Wi-Fi adapter for convenient remote monitoring and temperature adjustments through the Fujitsu AIRSTAGE Mobile App.

Optional Intelligent Occupancy Sensor: Compatible with an optional human sensor kit that detects room occupancy to help optimize energy savings and minimize unnecessary heating and cooling.

Multiple Fan Speed Options: Auto, High, Medium, Low, and Quiet settings provide customizable airflow and comfort for different room conditions.

Built-In Condensate Drain Pump: Integrated drain pump supports efficient condensate removal, providing additional installation flexibility and simplifying moisture management.

ProCore™ Corrosion-Resistant Indoor Coil: Features high-corrosion-resistant copper coils designed to improve durability and long-term reliability.

Flexible Cassette Grille Options: Compatible with optional white or black cassette grilles, allowing the indoor unit to complement different ceiling designs and interior finishes.

Optional Fresh Air Integration: Supports a compatible fresh air intake kit to introduce outside air and enhance indoor air quality and comfort.

Enhanced Comfort Controls: Supports optional wired and wireless remote controllers, weekly timer, 24-hour timer, sleep function, economy mode, powerful mode, automatic defrosting, and auto-restart functionality.

Smart Home & Building Integration: Supports compatible wired controllers, third-party thermostat interfaces, BACnet, Modbus, and home automation systems through optional accessories.

Auxiliary Heating Integration: Built-in external input/output functionality and multiple auxiliary heat control options allow integration with compatible supplemental heating systems and third-party devices.

Group Control Capability: Supports coordinated control of multiple compatible indoor units, providing convenient temperature management for larger residential and commercial installations.

Compact Outdoor Design: Space-saving condenser design and refrigerant piping lengths up to 98 feet provide flexible installation options for residential and light commercial applications.

Advanced External Device Integration: Supports compatible connections for fire alarms, door switches, humidifiers, auxiliary heating systems, and other third-party devices.

Specifications (Rated Conditions)

Cooling Capacity: 18,000 BTU Rated | 20,100 BTU Max | 3,100 BTU Min | SEER2: 26.3 | EER2: 13.6

Heating Capacity: 21,600 BTU Rated | 25,600 BTU Max | 3,100 BTU Min | COP2: 3.8

Cold-Weather Heating at 17°F: 14,400 BTU Rated | 19,300 BTU Max

Cold-Weather Heating at 5°F: 17,100 BTU Rated

HSPF2: 11.4 (Region IV) | 8.8 (Region V)

Electrical: 208/230 V, 1-Ph, 60 Hz | MCA: 14.8 A | Maximum Circuit Breaker: 20 A

Maximum Operating Current: 12.2 A Cooling | 14.8 A Heating

Indoor Airflow (Cooling): 459–618 CFM

Indoor Airflow (Heating): 459–618 CFM

Outdoor Airflow: 1,318 CFM Cooling | 1,154 CFM Heating

Indoor Sound Pressure: 28–34 dB(A) Cooling | 28–34 dB(A) Heating

Outdoor Sound Pressure: 52 dB(A) Cooling | 55 dB(A) Heating

Refrigerant: R-32 | Factory Charge: 2 lb 12 oz | Additional Refrigerant: 0.22 oz/ft

Piping: Liquid 1/4 in. | Gas 1/2 in. | Minimum Line Length: 16 ft | Maximum Line Length: 98 ft | Maximum Height Difference: 49 ft

Factory Pre-Charged Line Length: 66 ft

Outdoor Dimensions / Weight: 24-7/8 × 31-7/16 × 11-7/16 in. (H × W × D) | 84 lb

Indoor Dimensions / Weight: 9-11/16 × 33-1/16 × 33-1/16 in. (H × W × D) | 53 lb

Moisture Removal: 3.6 pints/hour

Drain Hose Connection: 13/16 in. I.D. | 1-1/16 in. O.D.

Outdoor Cooling Operating Range: -5°F to 122°F

Outdoor Heating Operating Range: -5°F to 75°F

Indoor Cooling Operating Range: 64°F to 90°F

Indoor Heating Operating Range: 60°F to 86°F

Included Components

Indoor Unit: AUUH18KUAS – 18,000 BTU-class AIRSTAGE Centauri circular-flow ceiling cassette indoor air handler featuring ProCore™ corrosion-resistant copper coils, built-in condensate drain pump, multiple fan speed options, ultra-quiet operation, and compatibility with optional Wi-Fi connectivity and occupancy sensing.

Outdoor Unit: AOUH18KUBS1 – 18,000 BTU-class AIRSTAGE heat pump condenser intended for the updated system pairing. INVERTER technology, R-32 refrigerant, and model-specific performance specifications should be confirmed against the updated outdoor unit documentation.

Cassette Grille: Compatible white (UTG-LCGVCW) and black (UTG-LCGVCB) grille options are available separately.

Remote Controller: Compatible wired controllers and an optional IR receiver kit with wireless remote controller (UTY-LBTUC) are available separately for convenient temperature, fan speed, and operating mode adjustments.

Ideal For

Homeowners and HVAC contractors seeking a premium, high-efficiency ceiling cassette mini-split heat pump capable of delivering consistent heating and cooling while maintaining a clean, unobtrusive interior appearance. The Fujitsu AUUH18KUAS and AOUH18KUBS1 combination is designed for applications such as living rooms, open-concept spaces, offices, retail environments, additions, and other residential or light commercial areas requiring efficient temperature control and balanced airflow distribution.

With its circular-flow ceiling cassette design, advanced INVERTER technology, whisper-quiet indoor operation, optional Wi-Fi connectivity, optional intelligent occupancy sensing, built-in condensate drain pump, and ProCore™ corrosion-resistant indoor coil , the AIRSTAGE Centauri system provides an excellent combination of comfort, energy efficiency, installation flexibility, and long-term reliability for year-round heating and cooling.