Building Management Systems

What are they?

A building management system (BMS) is a computer based central control system which is installed within a building to manage the operation of its services – heating, cooling, ventilation, hot water and lighting, and in some cases the integration of these services with the building envelope through control of shading devices and windows.

A BMS system comprises two key elements: controllers in the field, often in cabinets within plant rooms, and a computer ‘head end’.  Each controller sends and receives signals to / from the various items of building services equipment.  The computer ‘head end’ provides an interface with the controllers, showing real-time temperatures and plant operating conditions, allowing  the user to change and program system settings.

Advantages / Disadvantages

  • Programmable to meet tenant and owner requirements.
  • If well managed, will reduce energy consumption and costs and improve occupant comfort.
  • Requires skilled personnel to operate with regular monitoring and review.
  • Can result in unnecessary energy wastage and occupant discomfort if badly managed or operated.

Energy efficiency

A correctly set up and well managed BMS should result in energy savings  of up to 30% together with lower maintenance requirements. It provides building management the ability to implement more complex and demand-responsive strategies for managing building services in real-time.

Running costs

Low cost to run, but annual maintenance and regular monitoring is required to ensure control settings are appropriate for the building.

Retrofit / Improvement opportunities

An existing BMS can be easily upgraded or extended to provide greater control of a building’s services, although outdated systems may require a full replacement.

It is feasible and worthwhile to retrofit a BMS into most medium to large buildings where none exists currently.  Space is required in a plant area to accommodate the central control panel.

Applicable Buildings

BMS systems are applicable to all buildings, but generally better suited to larger buildings with complex services and systems. They are rarely installed in small or simple buildings such as strata offices, warehouses or shop units, which are more likely to benefit from a simple timeclock.

Floor plate implications


Occupant comfort

A building with a well-managed BMS installed should provide occupants with a high level of comfort in relation to heating, cooling, ventilation and  lighting requirements as well as providing improved visibility of space temperatures to enable monitoring of comfort issues when they occur.

Maintenance implications

A BMS requires regular monitoring and review by building management to ensure the system is operating efficiently and is well matched to the changing operational needs of the building.

Regular maintenance is required.  This is typically undertaken by the system supplier under a service agreement.  Sites that do not have a service agreement generally show a poorer level of efficiency and comfort as a result.


The easiest identifier for a BMS is the “head end” computer – which is typically located in the building managers office or in a plant room and has graphical information on the operation of items of plant.

Questions to ask

  • Does the building have a BMS?
  • Does the site have a maintenance contract that provides for regular maintenance of the BMS?
  • How old is the BMS?

More information

AIRAH Guide DA28 Building Management and Control Systems

Australian Government Department of Climate Change and Energy Efficiency (DCCEE) BMS Fact Sheet