Types of HVAC Systems for Commercial Buildings

For most commercial buildings, an HVAC system is the single largest energy-consuming installation on site. It governs temperature, ventilation, air quality and humidity across every occupied zone - from open-plan offices to server rooms and meeting suites. Selecting the right system type is a structural decision that affects running costs, maintenance schedules and regulatory compliance well beyond the initial installation.

This guide is written for facility managers, building operators and estate teams responsible for specifying or reviewing commercial HVAC systems. It covers the core system types, their practical trade-offs, and how integration with building automation and controls shapes long-term performance of each option.

The systems covered below are those most commonly specified for commercial buildings in the UK: split systems, VRF/VRV systems, packaged units, chiller systems and air handling units. Residential configurations such as domestic combi-boiler setups are outside the scope of this article. 

1. Split Systems

A split system divides its components between an indoor unit and an outdoor unit, connected by refrigerant pipework. The indoor unit - typically a fan coil or air handler - conditions the air within the space, while the compressor and condenser sit outside the building.

Split systems suit smaller commercial spaces: individual offices, retail units and server rooms where independent temperature control per zone is a priority. They require minimal ductwork, which keeps installation costs lower than central systems and reduces the disruption of retrofitting into occupied buildings.

The core limitation in commercial applications is scalability. Running multiple independent split systems across a large building becomes operationally complex without a central building management system to coordinate scheduling, fault monitoring and energy reporting.

Key characteristics

• Best for: Smaller commercial spaces, individual zones, retrofit installations
• Ductwork: Minimal or none required
• Control: Individual unit controls; BMS integration possible
• Energy efficiency: Moderate - inverter-driven units offer improved part-load performance
• Typical use: Offices, retail, server rooms, hospitality suites

2. VRF / VRV Systems

Variable Refrigerant Flow (VRF) systems - marketed by Daikin as VRV (Variable Refrigerant Volume) - connect a single or multiple outdoor units to a large number of indoor units across an entire building. Refrigerant flow to each indoor unit is adjusted continuously based on demand, allowing simultaneous heating in some zones and cooling in others.

VRF systems are one of the most energy efficient options available for medium to large commercial buildings. Their inverter-driven compressors modulate output in line with the building load, avoiding the energy waste of on/off cycling. They also support direct integration with BMS controls, enabling centralised scheduling, fault reporting and energy sub-metering across all zones.

The trade-off is upfront cost and installation complexity. VRF systems require careful pipe-length calculations and skilled commissioning. Refrigerant leak detection is also mandatory under UK F-Gas regulations, adding to compliance requirements.

Key characteristics

• Best for: Multi-zone commercial buildings, mixed-use sites, refurbishments
• Ductwork: Not required - refrigerant pipework connects indoor units directly
• Control: Centralised control with BMS integration; individual zone scheduling
• Energy efficiency: High - continuous modulation reduces energy consumption significantly
• Typical use: Office blocks, hotels, mixed-use developments, education buildings

3. Packaged HVAC Units

A packaged unit houses all HVAC components - compressor, condenser, evaporator and, in some configurations, a gas or electric heater - within a single casing. Most commercial packaged units are roof-mounted, with ductwork distributing conditioned air through the building below.

Packaged units are a practical choice for buildings with limited plant room space and where simplicity of installation and maintenance matters. Because all components sit in one location, servicing is straightforward. They are commonly found in retail sheds, warehouses, schools and light industrial units.

A well-specified packaged system connected to a building energy management system can maintain strong energy performance, but the fixed capacity of most standard units makes them less adaptable to variable internal loads compared with VRF systems.

Key characteristics

• Best for: Single-storey commercial buildings, retail, warehousing, schools
• Ductwork: Required to distribute conditioned air through the building
• Control: Zone control via dampers; BEMS integration available
• Energy efficiency: Moderate - performance depends on unit sizing and control strategy
• Typical use: Retail parks, distribution centres, light industrial, education

4. Chiller Systems

A chiller system cools water (or a water-glycol mix) which is then circulated around the building via pipework to fan coil units, ceiling cassettes or air handling units in each zone. Chillers are a central plant solution, typically installed in a plant room or on the roof for larger commercial and public buildings.

Chiller systems scale effectively across large, complex buildings where cooling loads are high and consistent. They support detailed metering and sub-metering at zone level, making them well-suited to landlord and tenant billing arrangements in multi-occupancy buildings. The water-based distribution network is also more thermally efficient over long pipe runs compared with direct refrigerant systems.

The main consideration is capital cost and plant room space. Chiller installations are significant infrastructure investments and require ongoing water treatment and BMS monitoring to maintain performance throughout their operational life.

Key characteristics

• Best for: Large commercial, public sector, healthcare, data centres
• Ductwork: Not required - chilled water distributed via pipework
• Control: Centralised; supports detailed sub-metering and BMS integration
• Energy efficiency: High at full load; modern inverter chillers maintain efficiency at part load
• Typical use: Hospitals, universities, large offices, government buildings

5. Air Handling Units (AHUs)

An air handling unit is a component rather than a standalone HVAC system, but it plays a central role in most large commercial HVAC configurations. An AHU draws in fresh outdoor air, filters and conditions it - heating, cooling, humidifying or dehumidifying as required - and distributes it through ductwork to occupied spaces.

AHUs are typically paired with a chiller or heat pump system to provide the heating and cooling energy. In commercial buildings with strict ventilation requirements - such as healthcare, laboratory or high-occupancy office environments - a well-specified AHU is essential for maintaining both temperature control and air quality. Heat recovery AHUs capture energy from exhaust air to pre-condition incoming fresh air, and are increasingly standard in new-build commercial specifications. They directly support facility management teams in meeting Part L and BREEAM targets.

Key characteristics

• Best for: Buildings with high ventilation requirements; new-build commercial
• Ductwork: Required - AHUs distribute conditioned air via duct networks
• Control: Integrated with BMS for supply air temperature, flow rate and scheduling
• Energy efficiency: High with heat recovery units - reduces heating energy demand significantly
• Typical use: Healthcare, laboratories, large offices, education, high-occupancy spaces

Side-by-Side Comparison

How to Choose the Right HVAC System

There is no single system type that suits every commercial building. The right choice depends on four primary factors:

• Building size and layout. VRF and chiller systems scale to large, multi-zone buildings. Split systems and packaged units suit smaller or simpler footprints.
• Existing infrastructure. Buildings with existing ductwork may be better suited to packaged units or AHU-based systems. Ductless VRF is often the more practical option for refurbishments.
• Occupancy and load profile. Buildings with variable or mixed loads - offices with fluctuating occupancy, hotels with differing room use - benefit from the part-load efficiency of VRF or inverter chiller systems.
• Controls and reporting requirements. Organisations with energy targets, ESOS obligations or multi-tenant metering requirements need a system that integrates cleanly with a building management system for zone-level data.

Regardless of which system type is selected, performance over its operational life is largely determined by how well it is controlled and maintained. A correctly specified HVAC system integrated with a building management system will consistently outperform a higher-specified system running on manual or timer-based controls.

Frequently Asked Questions

What are the main types of HVAC systems for commercial buildings?
The most common commercial HVAC system types are split systems, VRF/VRV systems, packaged units, chiller systems and air handling units. Each suits different building sizes, layouts and operational requirements. VRF and chiller systems are most commonly specified for large, multi-zone commercial buildings, while split systems and packaged units are more practical for smaller sites.

What is the most energy efficient commercial HVAC system?
VRF systems and modern inverter chiller systems offer the highest energy efficiency in commercial applications, particularly at part load. Their ability to modulate output in response to actual demand avoids the energy waste associated with fixed-output systems. Heat recovery AHUs also deliver significant efficiency gains in buildings with high ventilation requirements.

What is the difference between VRF and VRV?
VRF (Variable Refrigerant Flow) and VRV (Variable Refrigerant Volume) describe the same technology. VRV is a registered trademark of Daikin; all other manufacturers use the term VRF. Both refer to systems that adjust refrigerant flow to multiple indoor units based on real-time demand, enabling simultaneous heating and cooling in different zones of the same building.

Do commercial HVAC systems need a BMS?
Not all commercial HVAC installations require a full building management system, but BMS integration significantly improves energy performance, fault detection and compliance reporting. For buildings with ESOS obligations, multiple tenants or complex zoning requirements, BMS integration is effectively a practical necessity.

How long do commercial HVAC systems last?
Well-maintained commercial HVAC systems typically have a service life of 15 to 25 years, depending on system type and quality of ongoing maintenance. Chiller systems and AHUs tend to have longer operational lives than split systems when serviced correctly. Regular filter replacement, refrigerant checks and BMS-monitored performance reviews are the main factors in achieving full design life.

Specify HVAC Systems With Confidence

Johnson Controls works with building operators, estates teams and specifiers across the UK to design, install and optimise commercial HVAC systems that meet current energy and compliance standards. Our building automation and controls portfolio covers the full range of commercial HVAC types - from split system controls through to enterprise-scale BMS and chiller plant management.

Speak to our team to discuss system selection, controls integration or a performance review of your existing installation. Visit building automation and controls to get started.