The concept of energy efficiency revolves around reducing energy consumption without compromising with the actual facilities used. Generally, the conventional products are replaced with more sophisticated ones such as a normal filament bulb replaced with energy efficient LED light. The techniques employed under this discipline may result in energy savings as well as financial cost savings. Sustenance is maintaining these practices in the long run. The topics covered in this extensive book deal with the core subjects related to energy efficiency and sustenance. A number of latest researches have been included to keep the readers up-to-date with the global concepts in this area of study. This book, with its detailed analyses and data, will prove immensely beneficial to professionals and students involved in this area at various levels. It is also a beneficial read for engineers, environmentalists, ecologists and conservationists.