This book explores the important contribution of the built environment in the reduction of household energy consumption and in meeting the urgent challenge of the 2050 carbon reduction target. By examining trends in energy demand in UK and Europe across energy sectors for industry, commercial, domestic and transport, and exploring the reasons for change in energy use through practice and technology a concept of the energy hierarchy is introduced to help prioritise energy conservation over efficiency. Considering current UK and European government policy and the need to address sustainable development to drive the desired outcome of reduction in overall energy consumption, this book offers an accessible and inter-disciplinary approach to develop more sustainable, less energy-intensive systems and approaches that are socially acceptable and economically advantageous. It includes a broad geographical range of case studies the UK, Europe and further afield, with particular focus on Passivhaus in Germany, low energy houses in Scandinavia and Dongtan Eco city in China. Significant progress has been made in improving the thermal envelope of buildings but the actual energy demand has not declined as much as predicted. To tackle the technical failings in buildings energy use this guide offers an holistic, interdisciplinary approach which is needed to explore the technical, environmental and social challenges of designing and using low energy buildings, without which we are unlikely to meet our energy and carbon targets. This book combines the technical and the social explanation of energy consumption and how to challenge energy conservation making it suitable for all of those studying and teach on the courses highlighted in the UK marketing plan.