What Is A Building Automation System (BAS)? (Functions And Benefits)

Every day we hear more and more about the negative effects of climate change and the efforts for creating a sustainable environment. One of these efforts is making buildings more friendly for the environment and people that occupy it by incorporating a building automation system. 

What is a building automation system (BAS)? BAS is an intelligent system of both hardware and software, connecting heating, venting and air conditioning system (HVAC), lighting, security, and other systems to communicate on a single platform. This way the automation system is delivering you crucial information on the operational performance of a building as well as enhancing the safety and comfort of the occupants.

Usually, these types of automation systems are installed in brand new buildings or as part of a retrofitting process of an old building. The main purposes of building automation systems are reducing energy consumption, reducing maintenance costs, improving occupants’ comfort and productivity, and extending the life cycle of the utilities. 

What is the function of the building automation system (BAS)?

Buildings controlled by BAS often times are called smart or intelligent buildings. Why is that? Because the building is a more user-friendly, greener option, and less expensive to operate. Most of the processes are handled on a centralized control unit. More advanced systems can also be controlled remotely on different mobile devices using specific apps or platforms which contributes to the “smart building” term. 

Even though building managers have almost no direct input in the system, except when they need to make certain adjustments or optimizations, they usually don’t have time to be trained on how to use the system. 

They want to start working on the system from day one, to be able to find the relevant information right away so they can take the needed actions as soon as possible. With that being said, a well-designed building system should be easily accessible, intuitive, and remote. 

In simple terms the building automation system is just like the human brain, it tells the building equipment what to do, just like your brain tells your hands and legs to move. 

The core functionalities of BAS are keeping the heating, cooling, and ventilation within a certain range, humidity control,  lighting based on an occupancy schedule, proper functioning of the elevators, fire prevention, security and other critical systems in the building. 

It should also monitor the performance and potential failures of each utility and alert the managers of the buildings of detected malfunctions. 

For example, based on the data provided, BAS will regulate the temperature in the building according to the occupants’ needs, or through its sensors uncover that there is a need for improving the indoor air quality. 

Many people think of commercial buildings as static objects. However, there are so many processes in everyday life that make these buildings very vibrant. In only one day, the lights go on and off numerous times, vents letting air according to the needs of the employees, cooling and heating systems adjust the temperature and many more processes that have to be controlled properly. 

In practice, many offices incorporate motion sensors in their BAS to turn off lights when a room is not used. Or incorporate light sensors that detect the level of sunlight in the room, making sure that the BAS will adjust the indoor lights accordingly.

Which systems can be part of the BAS?

Some of the systems that can be incorporated in the BAS are as follows:

– HVAC systems

– Rooftop units

– Electrical systems, including lighting

– Security systems, including surveillance cameras and alarms

– Plumbing systems

– Fire alarms, and other emergency systems

– Elevators, and more.

Components of BAS

Building automation systems usually have 5 components. We will describe how these components interact and communicate with each other. 

1. Sensors

Sensors are devices that keep track of the humidity, temperature, lighting levels, how many people are in the room, if there is smoke in the rooms, and other parameters. After gathering this information, sensors transmit them to the controllers.

2. Controllers

Controllers are the brain of the building’s automation system. They collect all of the information from the sensors and according to that information, send commands to all connected systems, like HVAC systems, lighting systems, and more. 

3. Output devices

When the controller sends out a command, relays and actuators of the specific systems follow the new instructions or requirements. For example, turn on the heating or air conditioning at 6 am so when people come to work at 8 am, it’s properly heated or air-conditioned. 

4. Communication protocols

Every building automation system uses specific language to connect each individual component. Protocols such as BACnet and Modus help each component to send and receive information in order to adjust its settings and execute commands. 

5. Terminal interface

Every BAS has a user interface or terminal from which building and facility operators can access it. This terminal helps users to understand the information transferred between each component and gives the opportunity for making adjustments manually. 

The displays are visual with photo-realistic graphics. These graphics usually show each floor plan with each piece of equipment.  

What are the benefits of a BAS?

Modern BAS is equipped with many sensors and meters that provide many benefits not just for the building owners in terms of higher energy efficiency and maintenance costs, but for all employees and occupants of the building in terms of increased productivity and comfort. We divided the benefits into 3 major categories: 

Financial aspect

Even though implementing a BAS is a very expensive project, properly used one pays for itself over time by lowering the maintenance costs and utility bills. There are many studies that show by allowing BAS to monitor and adjust the HVAC system according to the occupancy, there can be cost savings from 10-30 percent.

When the use of every piece of equipment is optimized, it’s lifespan increases, which result in more indirect savings. 

Another important financial aspect is increasing the building’s overall value. Firstly, implementing a BAS is adding to the property’s value. Secondly, by offering better comfort as well as being more environmentally friendly, smart buildings are more attractive to tenants. This may result in higher rents.

Occupants’ comfort

Even though the occupant’s comfort can’t be presented in numbers, that doesn’t mean that should not be taken into account.

The biggest benefit of having an automated HVAC system is having proper temperature in winter and summer by regulating the temperature before anyone arrives in the building and after everyone leaves. Properly configured BAS can help to build operators to avoid unpleasant calls of employees feeling too hot or too cold,

Another benefit that contributes to the occupants’ comfort is the ability to maximize the use of natural light, then to regulate the amount of fresh air in the building and more. Usually, when people start feeling sleepy and lethargic it’s because of the lack of fresh air and oxygen.

Environmental aspect

Smart buildings tend to have fewer carbon footprints making them more sustainable and energy-efficient, which opens the door for receiving certifications, such as LEED, Energy Star, or Tenant Star. Many building owners are particularly interested in having a portfolio of energy-efficient buildings. 

Adopting the right building automation system

While implementing a BAS, building managers need to make sure that it will not become obsolete in a few years. The ever-changing technology poses a big challenge for these systems.

Building managers need to be up to date with all technology changes and how these changes can be implemented in the existing system. Building automation systems are not something that you will set and forget. It needs a proper strategy so it’s functional for many years. 

Many buildings have simple automation systems that provide limited information for its users, so the managers can’t easily optimize the systems due to lack of information. However, the full upgrade requires big investments, so many owners or managers decide to reduce these spendings by using the retrofitted system. 

Another challenge is using closed BAS. Closed BAS allows adding new features to the existing system only if those features are coming from the same company that created the BAS. This way, system upgrades will have limited features and limited flexibility. 


BAS (Building Automation System) is a combination of software and hardware that allows monitoring and automated control of many systems in the building including lighting, HVAC, security systems, and more. The purpose of the BAS is better control of the building’s systems and it’s accessible from a central terminal.

EMS (Energy Management System) doesn’t control the systems, instead, it monitors, collects, and analyzes data of energy consumption. By providing detailed reports and recommendations, helps in making decisions on how to optimize energy consumption and minimize costs.

These 2 systems can function separately, or complement one another.

What is BACnet?

BACnet (Building Automation Controls Network) is a communication protocol specifically designed for the communication of multiple devices included in the building automation system. It has specific rules, starting from what type of cable should be used to particular requests and commands.


Steve Todd

Steve Todd, founder of Open Sourced Workplace and is a recognized thought leader in workplace strategy and the future of work. With a passion for work from anywhere, Steve has successfully implemented transformative strategies that enhance productivity and employee satisfaction. Through Open Sourced Workplace, he fosters collaboration among HR, facilities management, technology, and real estate professionals, providing valuable insights and resources. As a speaker and contributor to various publications, Steve remains dedicated to staying at the forefront of workplace innovation, helping organizations thrive in today's dynamic work environment.

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