The world of Heating, Ventilation, and Air Conditioning (HVAC) plays a vital role in our daily lives, shaping the comfort, health, and energy efficiency of the spaces we occupy. Whether in homes, offices, factories, or hospitals, HVAC systems are the unsung heroes that regulate temperature, ensure proper ventilation, and maintain indoor air quality. This book, HVAC Fundamentals, is crafted to serve as a comprehensive guide for both aspiring and seasoned professionals, as well as anyone seeking to understand the foundational principles of HVAC. It is designed to bridge the gap between theory and practical application, making it an invaluable resource for engineers, technicians, students, and facility managers alike. As the HVAC industry continues to evolve with advancements in technology and increasing emphasis on sustainability, the demand for knowledgeable professionals has never been greater. This book aims to equip readers with the essential knowledge needed to navigate this dynamic field with confidence and competence. Throughout the chapters, you will find clear explanations of core concepts, practical examples, and insights into emerging trends. From understanding basic thermodynamics to exploring cutting-edge innovations in smart HVAC systems, this book is your gateway to mastering the fundamentals. I hope this work inspires you to delve deeper into the world of HVAC and contributes to your success in this ever-important field.