A HVAC BAS (Building Automation System) is a computer-based system that is used to control and monitor the heating, ventilation, and air conditioning (HVAC) systems in a building. It is designed to provide a comfortable and energy-efficient environment while reducing energy costs. The system consists of sensors, controllers, and actuators that are connected to a central computer. The computer collects data from the sensors and then uses this data to control the HVAC system. The system can be programmed to adjust the temperature, humidity, and air flow in the building based on the needs of the occupants. It can also be used to monitor the performance of the HVAC system and detect any potential problems. A HVAC BAS system can help reduce energy costs by ensuring that the HVAC system is running efficiently and that the building is being heated and cooled properly. Additionally, it can help reduce maintenance costs by detecting any potential problems before they become major issues.