The aim of this book is to present the fundamental principles of energy efficiency in construction. It is aimed at professionals, as well as masters' and engineering school students working in the field of building energy. Volume 1 covers the building context and issues, the building envelope and how to improve it using innovative materials and construction techniques, ventilation and lighting. Volume 2 is devoted to heating, air conditioning, domestic hot water production and centralized building management. The aim is to present more sustainable, energy-efficient solutions. Through these different aspects, the ambition of this book is to give the reader the tools and best practices to design, renovate or manage buildings, and thus ensure the comfort of occupants while reducing the impact on the environment.