Commercial air conditioning systems explained

Single split systems

A single split system pairs one outdoor condenser with one indoor unit, typically a wall-mounted or ceiling cassette unit. It is the simplest and cheapest commercial option, and remains the right choice for a single office, a small shop or a standalone meeting room where only one space needs conditioning.

The limitation is scale. Once a business needs several rooms cooled, running a separate single split for each one quickly clutters the outside of the building with condensers and increases both installation and maintenance overheads.

Multi-split systems

Multi-split systems connect one outdoor unit to several indoor units, commonly two to eight, each serving a different room but sharing one compressor. This suits small to medium offices, restaurants with a few distinct zones, or retail units with a shop floor and a back office, where a handful of rooms need independent temperature control without the expense of full commercial plant.

The trade-off is shared risk: if the outdoor unit develops a fault, every connected room loses cooling until it is repaired, so outdoor unit sizing has to reflect genuine simultaneous demand rather than the sum of every indoor unit's maximum output.

VRF systems

Variable Refrigerant Flow systems scale up multi-split thinking to a much larger level, connecting one or more large outdoor units to dozens of indoor units across a whole building, often under a central building management system. VRF suits larger offices, multi-tenant buildings and premises with a genuine mix of heating and cooling demand across different zones at the same time.

VRF costs more to design and install than split systems and needs an engineer familiar with the specific manufacturer's control architecture to service it properly, but it is far more space-efficient outdoors than dozens of individual condensers and gives centralised, zoned control.

Ducted systems

Ducted commercial air conditioning hides the indoor unit above a suspended ceiling or in a plant space, distributing air through ductwork to discreet grilles or diffusers in each room. It suits offices and retail spaces where a clean finish matters and there is enough ceiling void to route ducting, and it can serve several rooms from one indoor unit rather than fitting a separate unit per room.

It is most cost-effective when specified during a fit-out or refurbishment, while ceilings are already open, rather than retrofitted into a finished, occupied building.

Chillers

Chillers cool water rather than air directly, circulating chilled water to fan coil units around a building. They are generally reserved for larger commercial and industrial buildings, or sites with a mix of cooling loads including process cooling, where the scale justifies the additional plant and pipework involved.

For most offices, shops and restaurants we work with, a chiller is disproportionate to the requirement, but it becomes relevant on larger multi-floor or mixed-use sites.

Comparing the options at a glance

• Single split: one room, lowest cost, quickest install, no shared risk.
• Multi-split: several rooms, one outdoor unit, moderate cost, shared outdoor unit risk.
• VRF: many zones, higher cost, centralised control, simultaneous heating and cooling possible.
• Ducted: hidden finish, needs ceiling void, best specified during a fit-out.
• Chillers: large or mixed-load sites, highest complexity, rarely proportionate for small premises.

Matching the system to your business

The right system depends far more on building layout, ceiling access and how many separate zones need independent control than on budget alone. A single split can be entirely wrong for a business that will grow into three more rooms next year, just as VRF can be wasteful for a business that only ever needs to cool a single office suite.

If you're weighing up options for a commercial site, get in touch for a free quote and site visit. We'll look at your building, your usage pattern and your budget before recommending a system, rather than starting from a preferred product line.