The new edition of a bestseller, this book is a completely revised and expanded resource and one of the leading educational references for energy managers, energy professionals, and those entering the field of energy management and energy engineering. It is the most widely used college and university textbook in the field, as well as one of the most widely used resources for professional development training.Revised chapters include energy auditing, energy bills, life cycle costing, electrical distribution systems, boilers, steam distribution systems, control systems and computers, energy systems maintenance, insulation, compressed air, renewable energy sources and water management, distributed generation, and creating green buildings.Building on this foundation, the book provides a practical, systems-based approach to demand-side energy and carbon management across residential, commercial, institutional, and industrial facilities. It connects core building systems such as HVAC and electrical infrastructure with wider decarbonisation objectives, helping readers understand how integrated optimisation can improve efficiency, reduce operating costs, and lower emissions.Grounded in climate science, it emphasises the urgency of the net-zero transition while also addressing resilience and long-term energy system performance. It also highlights the importance of human factors in energy management, including behaviour, organisational processes, and stakeholder engagement, ensuring technical solutions are effectively implemented in practice.