Mitsubishi PAA-BA18NL & PUZ-AH24NL 18,000 BTU 17.9 SEER2 Cased Coil Heat Pump System – R454B

Mitsubishi PAA-BA18NL & PUZ-AH24NL: 18,000 BTU Heat Pump Split System

The Mitsubishi PAA-BA18NL indoor cased coil paired with the PUZ-AH24NL outdoor heat pump delivers efficient year-round heating and cooling performance for residential and light commercial applications. Designed for compatibility with gas furnaces and Mitsubishi intelli-HEAT® systems, this 18,000 BTU split system combines inverter-driven efficiency, flexible installation, and quiet operation for dependable comfort in homes, offices, restaurants, retail spaces, and retrofit HVAC projects.

The PAA-BA18NL indoor unit is engineered for compatibility with most ANSI-certified gas furnaces and supports Mitsubishi’s intelli-HEAT® technology for intelligent switchover between heat pump and furnace operation during colder weather conditions. This hybrid functionality helps optimize comfort, improve energy efficiency, and reduce carbon impact. The unit also supports automatic heating and cooling mode changeover to maintain consistent indoor temperatures throughout the year. Flexible multi-position installation supports horizontal and vertical configurations—including left, right, upflow, and downflow orientations—making the system adaptable to a wide range of HVAC layouts.

The PUZ-AH24NL outdoor condenser utilizes Mitsubishi’s INVERTER-driven twin rotary compressor technology to deliver precise temperature control and energy-efficient operation. Designed for dependable operation in a variety of climates, the system provides heating performance down to -4°F outdoor ambient temperatures and cooling operation up to 115°F. The outdoor unit includes Blue Fin anti-corrosion coating and seacoast protection to guard against salt, sulfur, and airborne contaminants that can reduce performance and equipment lifespan. Optional wind baffles allow cooling operation down to 0°F for specialized low-ambient applications.

Despite its compact footprint, the system delivers strong airflow performance up to 812 CFM while maintaining quiet operation with outdoor sound levels as low as 49 dB(A) in cooling mode and 52 dB(A) in heating mode. The reverse-cycle defrost system improves winter reliability, while inverter-driven capacity control helps reduce temperature swings and energy consumption. ENERGY STAR® certification and high-efficiency ratings help reduce operating costs while maintaining dependable year-round comfort.

The system also supports advanced control and connectivity options, including Mitsubishi’s Comfort app, kumo cloud®, wired and wireless remotes, BACnet®/Modbus® interfaces, and third-party thermostat compatibility for flexible comfort management and smart home integration.

General Information

System Type: Cased coil indoor unit + single-zone heat pump outdoor unit
Models: Indoor – PAA-BA18NL | Outdoor – PUZ-AH24NL
Capacities: 18,000 BTU Cooling (Max 18,500 | Min 9,500)
Heating Capacity: 22,600 BTU at 47°F | 10,200 BTU at 17°F
Room Size: Ideal for residential and light commercial spaces up to ~700–1,000 sq ft
Operating Modes: Heating & Cooling
ENERGY STAR®: Yes
Refrigerant / Factory Charge: R-454B, 7 lb 11 oz (pre-charged for 100 ft line length)

Key Features

INVERTER-Driven Compressor: Efficient, precise heating and cooling control
intelli-HEAT® Compatibility: Hybrid furnace integration capability
Auto Changeover: Automatically switches between heating and cooling modes
High Airflow Output: Up to 812 CFM for even air distribution
Quiet Operation: Outdoor sound levels as low as 49 dB(A)
Flexible Installation: Multi-position horizontal or vertical installation
Blue Fin & Seacoast Protection: Corrosion-resistant outdoor coil protection
Reverse-Cycle Defrost: Improved winter heating reliability
ENERGY STAR® Certified: High-efficiency operation for reduced energy costs
Smart Controls: Comfort app compatible, wired/wireless remotes, thermostat interfaces

Specifications (Rated Conditions)

Cooling Capacity: 18,000 BTU (Max 18,500 | Min 9,500) | SEER2: 17.9 | EER2: 12.8
Heating Capacity: 22,600 BTU at 47°F | 10,200 BTU at 17°F | HSPF2: 8.8
Electrical: 208/230 V, 1-Ph, 60 Hz | MCA: 22 A | MOCP: 37 A
Indoor Airflow: 424–812 CFM
Outdoor Sound: 49 dB(A) Cooling | 52 dB(A) Heating
Piping: Liquid 3/8 in | Gas 5/8 in | Max line length: 100 ft | Max height: 100 ft
Outdoor Dimensions / Weight: 37-13/32 × 14 × 37-1/8 in | 155 lb
Indoor Dimensions / Weight: 17-9/16 × 21-7/16 × 27-1/2 in | 54 lb
Drain Connection: 3/4 in O.D.

Included Components

Indoor Unit: PAA-BA18NL cased coil indoor unit
Outdoor Unit: PUZ-AH24NL heat pump condenser

Ideal For

Residential and light commercial applications requiring efficient year-round heating and cooling with flexible furnace compatibility and quiet inverter-driven performance. The Mitsubishi PAA-BA18NL & PUZ-AH24NL system delivers dependable comfort, energy-efficient operation, and durable corrosion-resistant construction for long-lasting reliability.