The energy efficiency services sector (EESS) is poised to become an increasingly important part of the U.S. economy. Energy supply and climate change concerns, volatile and increasing energy prices, and a desire for greater energy independence have led many local, state and national leaders to support an increasingly prominent role for energy efficiency (EE) in U.S. energy policy. The national economic recession has also helped to boost the visibility of energy efficiency as part of a strategy to support economic recovery. This book examines key aspects of the EESS by describing the current job composition, the current workforce size, projections for growth in spending and employment and key issues that may limit this growth.