Start with the ceiling, not the brochure
For most commercial spaces the choice between indoor unit types is decided less by the equipment and more by the room: whether there is a false ceiling, how high it is, how the space is laid out and how much of the equipment you are happy to see.
Here is how the four common indoor unit types compare when you look at them that way.
The four options
- Cassette
- Sits flush within a false ceiling with only a square panel visible, and sends air out in several directions, so air spreads evenly through open rooms. Often considered for offices, showrooms, cafés and clinics. Needs a false ceiling with enough space above it for the unit.
- Ducted (ductable)
- The unit is concealed above the ceiling and delivers air through ducts to grilles or slot diffusers, so only discreet grilles show. Suits premium homes, offices, hotels and conference rooms where the interior should stay clean. Needs more ceiling depth for the unit and the ductwork, and access panels for service.
- Ceiling suspended
- Mounted directly under the ceiling and sends air along the room. A clean option where there is no false ceiling, such as cafés, shops or halls with an exposed slab.
- Floor standing
- A free-standing unit for larger open areas, with no wall or ceiling mounting needed. Useful in shops, showrooms, halls and lobbies, or where ceiling work isn't possible.
Cassette or ducted: the usual decision
When a space has a false ceiling, the choice usually comes down to these two. A cassette is the simpler installation and spreads air well across an open floor; its panel is visible in the ceiling. A ducted unit disappears completely, which is why it is chosen for boardrooms, reception areas and premium interiors, but it needs more ceiling depth and careful duct design so that air reaches every part of the room quietly.
In larger buildings both can run on the same VRV / VRF system, so a project can use cassettes in open areas and ducted units in cabins and meeting rooms.
Questions to settle before choosing
- Ceiling
- Is there a false ceiling, and how much space is above it?
- Layout
- Is it one open area, or cabins and rooms that need their own control?
- Use
- How many people, what equipment and lighting, and which hours of the day?
- Appearance
- Should the equipment be visible, discreet or completely hidden?
- Maintenance
- Can technicians reach the units and filters without disturbing the business?
Getting the size right
Whichever type you choose, the capacity has to match the room. An undersized unit runs flat out and still struggles on hot afternoons; an oversized one switches on and off too often. That is why we calculate cooling needs properly before we quote.