Building automation system is enabler technology for zero energy buildings that ensures optimum energy performance, occupant comfort, and reliability. The automation system integrates all building subsystems including HVAC, lighting, energy management, and communication networks into a unified control system that enables real-time monitoring and decision-making. The system participates in demand response programs by adjusting building loads in response to grid signals contributing to operational costs reduction. Despite these benefits, certain challenges are identified related to standardization, interoperability, cybersecurity, and the large-scale deployment.