Energy Audit of Building Systems: An Engineering Approach , Fourth Edition addresses the critical intersection between energy efficiency and building performance optimization. It provides specialized knowledge and systematic approaches needed to evaluate existing buildings while achieving maximum energy savings and carbon-neutral operation. The new edition expands coverage to include dynamic and demand response technologies such as switchable glazing systems, phase change materials, and PV-integrated shading devices. It also includes a new chapter covering proven systems and effective analysis approaches for electrifying existing buildings. Enhanced problem sets and case studies provide practical applications for both residential and commercial building retrofits. This book will benefit building energy auditors, HVAC engineers, architects, facility managers, and advanced undergraduate students seeking specialized training in building energy management. Instructors will be able to utilize a Solutions Manual for their course.