Comparison · System selection
VRF vs split air conditioning — where the crossover point actually sits.
Split is not a cheaper VRF, and VRF is not an oversized split. This is the engineer's decision matrix — capacity, capex, running cost, controls and statutory exposure.
In short
Choose split below ~30 kW when zones share schedules and BMS isn't needed. Choose VRF above 30 kW, when heat recovery pays for itself, or when a landlord specifies a single condenser bank. The crossover is 5–6 zones or ~30 kW total load.
Side-by-side
The numbers that actually decide it.
| Attribute | Split system | VRF |
|---|---|---|
| Best for | 1–4 zones, up to ~30 kW total | 5+ zones, whole-building, 12–150 kW |
| Indoor units per outdoor | 1 (single) or 2–5 (multi-split) | Up to 64 on one condenser |
| Heat recovery | Not available | Yes — simultaneous heat + cool between zones |
| Pipe run limits | Typically ≤ 30 m | Up to 165 m total, 90 m from condenser |
| Capex per kW | £450–£900 / kW installed | £700–£1,400 / kW installed |
| SEER (typical) | 6.1 – 7.2 | 6.8 – 8.4 (with heat recovery) |
| Controls | Wired or wireless per unit | Centralised BMS / BACnet / Modbus |
| TM44 exposure | Trips 12 kW threshold on most sites | Always subject to TM44 |
Choose split when
Simple, single-tenancy, capex-led.
- —Fit-out is a single tenancy with 1–4 rooms
- —Landlord restricts riser or roof space for pipework
- —Budget is the dominant constraint and heat recovery isn't needed
- —Zones run on similar occupancy schedules
Choose VRF when
Multi-zone, BMS-integrated, TCO-led.
- —Whole-floor, multi-floor or multi-tenant building
- —Simultaneous heating and cooling required (e.g. server room + offices)
- —BMS integration is specified
- —Long pipe runs from a roof-mounted condenser
- —5-year TCO matters more than day-one capex
Deeper reading: how to size a commercial system, cost per kW guide, Daikin vs Mitsubishi Electric, HVAC glossary.
VRF vs split FAQs
The questions procurement teams ask before signing off.
What is the difference between VRF and split air conditioning?
A split system pairs one outdoor condenser with one (or a few) indoor units on a shared refrigerant loop. VRF (Variable Refrigerant Flow) uses inverter-driven compressors to modulate refrigerant delivery to up to 64 indoor units across long pipe runs, and higher-tier VRF adds heat recovery — moving heat from a cooling zone into a heating zone at the same time.
Is VRF more expensive than split?
Yes at capex — VRF typically installs at £700–£1,400/kW versus £450–£900/kW for split. Over a 10-year period VRF usually wins on running cost above 30 kW total load because of higher SEER and heat recovery, but below 30 kW split is generally the better commercial choice.
Can you mix VRF and split on the same building?
Yes, and it's common. Offices might run on VRF for zone flexibility while an adjacent standalone server room runs on a dedicated split or DX close-control unit for redundancy — kept independent of the main HVAC on purpose.
Does VRF need a BMS?
No, but it benefits from one. VRF can run on the manufacturer's own centralised controller. A BMS integration via BACnet or Modbus is worth specifying if the building already uses one for lighting, metering or access — it turns HVAC scheduling into a single-pane operation.
What is heat recovery VRF?
Heat recovery (HR) VRF is a 3-pipe system that lets some indoor units cool while others heat simultaneously, moving heat between them rather than rejecting it outside. Real SCOP figures above 7 are typical, and it's the most efficient option for mixed-use buildings.
Not sure which fits