Split, cassette, ducted or VRF: which commercial air conditioning system?
How to choose between wall-mounted splits, multi-splits, ceiling cassettes, ducted units and VRF for offices, shops and hospitality premises.
Short answer
Choose a wall-mounted split for one or two small rooms, ceiling cassettes for open spaces with a suspended ceiling, ducted units where appearance matters, and VRF once you need more than about six to eight indoor units or central control. The heat load, ceiling, outdoor space and budget decide the rest.
Wall-mounted splits and multi-splits
A split system has one indoor unit and one outdoor unit. It is the cheapest and quickest option for a single office, treatment room, back office or small shop. A multi-split connects two to five indoor units to one outdoor unit, saving wall space, but every room on it depends on that one compressor.
- Best for: small rooms, solid ceilings, limited budgets
- Watch out for: units blowing onto desks, multi-split single point of failure
Ceiling cassettes
Cassettes sit in a suspended ceiling and blow air in up to four directions. They suit open-plan offices, shops, restaurants and classrooms. Compact models fit a 600 mm grid; full-size cassettes cover larger areas. Most include a condensate pump.
- Best for: open spaces with a ceiling void
- Watch out for: void depth, cleaning access
Ducted units
Ducted units hide above the ceiling and deliver air through grilles or slot diffusers. They are the most discreet option for receptions, boardrooms, hotel rooms and premium retail, but need deeper voids, ductwork and an access panel.
- Best for: appearance, quiet rooms
- Watch out for: void depth, return air path, access for filters
VRF and VRV systems
VRF connects many indoor units of different types to shared outdoor plant, with each zone controlled separately. Heat recovery VRF can cool some rooms while heating others. It is the standard choice for multi-floor offices, hotels and larger buildings.
- Best for: 6–8+ indoor units, central control, limited outdoor space
- Watch out for: refrigerant charge limits in small rooms, leak-check duties
Questions to decide
- How many rooms or zones need different temperatures?
- Is there a suspended ceiling, and how deep is the void?
- Where can the outdoor unit go — and will the landlord and planners accept it?
- Do you want heating from the same system?
- Are there rooms that must be cooled 24/7, such as a comms room?
Questions
Can we mix cassettes and ducted units?
Yes. Multi-split and VRF systems can combine different indoor unit types on one outdoor unit.
Which system is cheapest to run?
Running cost depends more on correct sizing, controls and maintenance than system type. Modern inverter splits and VRF are all efficient when designed well.
Related services
- Split and multi-split systems
- Ceiling cassette air conditioning
- Ducted air conditioning
- VRF and VRV systems
This guide is general information, not legal advice. Rules can change; check the current position with the relevant authority for your building.