Why do organisations 'leave money on the floor' by neglecting highly cost effective measures to improve energy efficiency? This question lies at the heart of policy debates over climate change and is a focus of continuing dispute within energy economics. This book explores the nature, operation and relative importance of different barriers to energy efficiency through a comprehensive examination of energy management practices within a wide range of public and private sector organisations. The authors use concepts from new institutional economics to explain individual and organisational behaviour in relation to energy efficiency, and identify the mechanisms through which such barriers may be overcome. In doing so, they are able to shed new light on the 'barriers debate' and provide a valuable input to the future development of climate policy.Combining a critical evaluation of different theoretical perspectives with detailed case study research, this significant new book analyses how and why organisations waste energy and suggests practical policy measures to help prevent these losses. It will be required reading for professional economists, academics and students with an interest in energy use, environmental policy and organisational economics. It will also be highly relevant for policymakers and consultants working on the important policy issues surrounding energy efficiency and climate change.