A systematic approach to evaluating and analyzing a wide range of measures and opportunities for saving energy and reducing the operating costs of existing buildings. It provides a review of the basics of energy efficiency improvements of building systems, including the building envelope, the HVAC distribution systems, and the heating/cooling power plant equipment. Most importantly, the book supplies energy managers with valuable technical information, practical rules, and procedures for performing an energy audit for both residential and commercial buildings. It also treats issues such as indoor air quality problems and water management concerns, and describes the tools available to measure and verify energy savings after retrofitting a building. There are exercises in each chapter.