Buildings are important consumers of energy
in fact, they represent 30-45% of the global energy use and one-third of total greenhouse gas emissions, as well as contributing to the urban heat-island effect. In consequence, the correct design and execution of buildings, use of new materials that reduce energy demand, and efficient use of renewable energy are all necessary to reduce the impacts that occur during their life-cycle. This book shows some examples, focused on improving the energy-efficiency of buildings, in accordance with circular economy policies and life-cycle phases, including design, construction and use. The editor wishes to thank all the authors for contributing to this book, as well as to the assistance of MDPI's editorial office.