WALTHAM, Mass. – January 4, 2012 – American DG Energy Inc. (NYSE Amex:ADGE), a leading On-Site Utility, offering clean electricity, heat, hot water and cooling solutions to hospitality, healthcare, housing and athletic facilities, has reached an agreement to supply clean energy to multiple residential buildings located in New York. Under the terms of the fifteen-year agreement, the Company will install fourteen combined heat and power (CHP) systems at multiple residential buildings, managed by RY Management, a property management company. The CHP systems, totaling 1050 kW, will be owned and operated by American DG Energy. The property management company will receive a discount on the energy produced by the CHP systems and reduce the emissions of its managed properties. The value of the agreement to the Company is $27.4 million.

“This is a very significant order for American DG Energy and it prepares us for a very exciting 2012,” said John N. Hatsopoulos, CEO of American DG Energy. “As the core piece of our strategy, the Company continues to pursue large property holders to accelerate our growth with multi-property deals.”

American DG Energy will produce clean energy in the form of electricity and domestic hot water for the properties at a price lower than the local energy utility. Because the property management company opted for the Company’s On-Site Utility energy solution, the properties will pay only for the energy used and will avoid all capital, installation and operating costs. The Company will also handle all service, maintenance and repair; therefore, neither RY Management nor its managed properties will need to provide manpower to support the energy equipment.

The specific CHP systems planned for the properties are expected to reduce the emissions of the properties by 4,386 tons of carbon dioxide each year. This reduction is equal to removing the carbon emissions of 724 cars each year.*

*Figures were calculated using the EPA CHP Partnership emissions calculator.