At a time when technology is advancing rapidly, smart buildings have become a driving force of innovation, leveraging IoT capabilities to enhance their efficiency and convenience. However, these digital transformations also introduce complex security challenges. This paper explores Intrusion Detection Systems (IDSs) in smart buildings, addressing the escalating security concerns. Through a selection of research papers, we highlight various strategies and their strengths to counter cyber threats, while presenting recommendations and open research issues. Highlighting the integration of Intrusion Detection Systems with authentication mechanisms, we propose a unified security approach, improving network protection and user verification. Emerging trends such as advanced machine learning and distributed processing are promising, while challenges such as scalability and real-time processing require constant attention. As smart buildings evolve, it will become critical to refine intrusion detection techniques to ensure their effectiveness against dynamic threats. This study serves as a roadmap for improving network security and safeguarding against cyber threats in smart buildings.