Ameresco, Inc., is a provider of energy efficiency solutions for facilities throughout North America. The Company's services include upgrades to a facility's energy infrastructure and the construction and operation of small-scale renewable energy plants. Its principal service is the development, design, engineering and installation of projects that reduce the energy and operations and maintenance (O&M) costs of its customers' facilities. These projects include a variety of measures customized for the facility and designed to improve the efficiency of major building systems, such as heating, ventilation, air conditioning and lighting systems. Ameresco, Inc. provides its services primarily to governmental, educational, utility, healthcare and other institutional, commercial and industrial entities. In June 2013, Ameresco Inc acquired ESP, an energy management consulting company consisting of the Energy Services Partnership and ESP Response, located in Castleford, United Kingdom.