Mitsubishi 12,000 BTU R454B Ceiling Cassette Heat Pump System
Rated at a full ton of cooling and 15,000 BTU/h of heating at 47°F, the SUZ-AA12NL-U1 and SLZ-AF12NL-U1 combination is the most commonly specified size in Mitsubishi's R454B cassette family — enough capacity for a genuine open room without stepping up to the heavier outdoor chassis. It earns 20.3 SEER2, 12.5 EER2, and 9.7 HSPF2, and it is ENERGY STAR certified. Both the SLP-18FAU ceiling grille and the MHK2 kumo touch wireless wall thermostat are packed with the system, so the installer opens one shipment and has every piece needed to finish the ceiling and give the owner a real wall control. The 22-7/16 in. square cassette sits flush in a 2 ft. × 2 ft. grid and throws conditioned air in four directions, which is why it shows up so often in conference rooms, classrooms, and open retail floors.
Is a 12,000 BTU Ceiling Cassette System the Right Size?
A one-ton cassette generally lands on rooms in the range of 450 to 600 square feet, and it is usually the right answer when a single space is too large for a 9,000 BTU head but does not carry the glass load or occupancy that pushes a room to 15,000 BTU. Its useful trait is breadth: the inverter turns down to 3,000 BTU/h and climbs to a full 12,000, so one system can hold an empty conference room at setpoint overnight and still recover it when twelve people walk in.
Load, not floor area, decides the size. A 500 square foot room with a west wall of windows, a projector, and a dozen laptops can easily exceed a ton, while the same footprint as an interior classroom with good insulation may not. Ceiling height matters more with a cassette than with a wall unit, since the air has to be thrown down from the plenum — above roughly 10 ft. the throw pattern and vane setup need attention. In heating, this pairing still delivers 9,800 BTU/h at 17°F outdoors, so verify against your winter design temperature before assuming the 15,000 BTU rating carries through the season.
Ideal for: Conference and meeting rooms, classrooms and training rooms, open retail floors, restaurant dining areas, physical therapy and treatment rooms, larger primary suites, break rooms, and converted garage or studio spaces with a drop ceiling.
Need more capacity? Step up to the 15,000 BTU Mitsubishi SUZAA15NL & SLZAF15NL Ceiling Cassette System for rooms carrying heavier solar gain, higher occupancy, or greater open floor area.
Recommended applications are general guidelines only. Actual system requirements depend on insulation, window area, ceiling height, occupancy, internal heat gain, and local design temperatures. Request free sizing assistance, contact Budget Heating, or call 813-885-7999.
What's Included
| Outdoor Heat Pump | SUZ-AA12NL-U1 — 12,000 BTU/h Inverter Heat Pump Condenser |
|---|---|
| Indoor Unit | SLZ-AF12NL-U1 Four-Way Ceiling-Recessed Cassette |
| Cassette Grille | SLP-18FAU Architectural Grille — Included |
| Controller | MHK2 kumo touch RedLink Wireless Wall Thermostat — Included |
| Application | Single-Zone Ductless Ceiling Cassette Heat Pump System |
| Refrigerant | R454B (A2L, Low GWP) |
| Cooling / Heating | 12,000 BTU/h Cooling — 15,000 BTU/h Heating at 47°F |
| Efficiency | 20.3 SEER2 / 12.5 EER2 / 9.7 HSPF2 — ENERGY STAR Certified |
| Electrical | 208/230V, Single Phase, 60 Hz — MCA 14A, MOCP 23A |
| Line Set Connections | 1/4 in. Liquid × 3/8 in. Gas, Flared |
| Maximum Line Length | 65 ft. with 40 ft. Maximum Height Difference |
| Manufacturer Warranty | 10 Years |
This package removes the two items most often forgotten on a cassette quote. The grille is a required component of the SLZ chassis, not an accessory, and the wireless control is what turns a ceiling cassette into something an office manager can actually operate — both are in the box here. The SUZ-AA12NL-U1 shares the same 31-1/2 in. cabinet and 3/8 in. gas connection as the 9,000 BTU model, so if you are replacing a smaller cassette the existing pad, brackets, and line set diameter often carry over, though R454B requires new piping. Field-supplied items are the line set, control wire, and disconnect; see the mini split copper and accessories section for matched flare line sets, wall sleeves, and condensate hardware. Additional single-zone options are grouped under single zone high efficiency heat pump systems. A2L-trained, EPA 608 certified installation is required.
Outdoor Unit & Ceiling Cassette Features
SUZ-AA12NL-U1 Outdoor Heat Pump
- Full 12,000 BTU/h cooling with a 3,000 BTU/h minimum, giving a four-to-one turndown on a single zone
- ENERGY STAR certified at 20.3 SEER2 and 12.5 EER2 with a 960 W rated cooling input
- 15,000 BTU/h heating at 47°F with a 3.2 COP, and 9,800 BTU/h still available at 17°F
- Same compact 31-1/2 in. × 11-1/4 in. × 21-11/16 in. cabinet as the 9,000 BTU model at 81 lb.
- Retains 3/8 in. gas and 1/4 in. liquid flare connections, so line set sizing matches the smaller unit
- 49 dB(A) cooling and 51 dB(A) heating sound pressure from a single variable-speed propeller fan
- 1,229 CFM cooling and 1,172 CFM heating airflow across the outdoor coil
- R454B low-GWP refrigerant with a 2 lb. factory charge covering line sets to 25 ft.
- MCA of 14A and MOCP of 23A on 208/230V single-phase power
- Ambient operation from 115°F down to 23°F in cooling and -4°F in heating
SLZ-AF12NL-U1 Four-Way Ceiling Cassette
- Three-speed blower delivering 230, 280, and 335 CFM to cover both idle and full-occupancy conditions
- Sound pressure of just 25 dB(A) on low and 34 dB(A) at high fan speed
- 72 selectable airflow patterns from independently driven four-way vanes
- Vanes can be individually blocked to avoid drafting a conference table or a seated workstation
- Fits a standard 24 in. × 24 in. ceiling grid opening at 22-7/16 in. square and 8-3/16 in. deep
- Integral condensate lift pump with 33 in. of head, allowing drainage above the ceiling plane
- SLP-18FAU grille included, providing the finished flush ceiling appearance
- MHK2 kumo touch wireless thermostat included for wall-mounted setpoint and scheduling control
- Optional 3D i-see Sensor available for occupancy detection and automatic airflow redirection
- 31 lb. chassis with washable long-life filter accessible from below through the grille
Specifications & Manuals
Reference the SUZ technical specifications and installation manual for outdoor clearances, line set limits, and electrical requirements, and the SLZ installation instructions for ceiling opening dimensions, grille mounting, and condensate lift routing. Service manuals and parts lists support diagnostics and component ordering after startup.
Frequently Asked Questions
Is the 12,000 BTU cassette system ENERGY STAR certified?
Yes. The SUZ-AA12NL-U1 and SLZ-AF12NL-U1 pairing is listed as ENERGY STAR certified on the Mitsubishi submittal at 20.3 SEER2, 12.5 EER2, and 9.7 HSPF2.
How low can this system turn down when the room is empty?
The inverter modulates down to 3,000 BTU/h in cooling. That low end is what keeps an unoccupied conference room from short cycling and lets the unit hold humidity down between meetings.
Can I mount the cassette in a hard ceiling instead of a grid?
Yes, provided you frame an opening sized to the SLZ-AF12NL-U1 and leave the plenum depth and service access the installation instructions call for. The SLP-18FAU grille trims out the opening either way.
Does the cassette need a gravity drain, or will it pump condensate?
A condensate lift pump is built in and will raise water up to 33 in. above the unit, which usually lets the drain run above the ceiling plane to an existing waste line rather than sloping across the room.
What line set size does the SUZ-AA12NL-U1 use?
1/4 in. liquid and 3/8 in. gas, both flared. That matches the 9,000 BTU unit, but not the 15,000 or 18,000 BTU models, which move up to a 1/2 in. gas line.
Will one MHK2 control more than one cassette?
The MHK2 kit included here is configured for this single-zone system. Multi-zone and grouped-control arrangements use different accessories — see the thermostats and controls selection or contact Budget Heating for the right configuration.
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