Tecogen Elects Two New Directors /
$3.4 Million of Debt Converted into Common Stock

Waltham, Mass. - October 1, 2008 - Tecogen Inc., a leading manufacturer of natural gas fueled commercial and industrial cooling and cogeneration systems, today announced that it has elected Dr. Ahmed F. Ghoniem and Mr. Parimal S. Patel to its board of directors, bringing the company's total number of directors to seven.

Tecogen Inc. also announced that its board of directors approved the conversion of 6% Demand Notes in the aggregate amount of $3.4 million in principal and accrued interest, held by George and John Hatsopoulos, into the Company's common stock.

"We are very fortunate to have Dr. Ghoniem and Mr. Patel join our board, since both are prominent experts in fields directly related to our core business of alternative power generation and energy conservation, and we look forward to the valuable insight they will provide to our management and board," said Ms. Angelina Galiteva, chairperson of the board of Tecogen Inc. "Likewise, we are very pleased that George and John Hatsopoulos converted a big portion of their outstanding debt. This conversion clearly indicates their confidence in the future of Tecogen."

Dr. Ahmed F. Ghoniem is the Ronald C. Crane (1972) Professor of Mechanical Engineering at the Massachusetts Institute of Technology. He is the director of the Center for 21st Century Energy, and the head of Energy Science and Engineering at MIT. Professor Ghoniem plays a leadership role in many energy-related activities, initiatives and programs at MIT. Mr. Ghoniem holds a Ph.D. in Mechanical Engineering from the University of California, Berkeley, and an M. S. and B.S. in Mechanical Engineering from Cairo University, Egypt.

Mr. Parimal Patel was the Assistant Corporate Vice President for Research and Development of Thermo Electron. He was also the Chief Operating Officer of Thermo Energy Systems Corporation, a subsidiary of Thermo Electron devoted to the construction and management of large power generation stations, generally operated with bio-fuels (municipal solid waste, wood, and bio-mass) and applied as combined heat and power (CHP) systems. Mr. Patel holds a Master's Degree from Polytechnic Institute of Brooklyn, New York, and a Bachelor of Engineering Degree from the University of Baroda, India.

About Tecogen
Tecogen Inc. operates in the distributed generation market and is a leading manufacturer of natural gas fueled commercial and industrial cooling and cogeneration systems. Tecogen has an installed base of more than 2,000 units, which it supports through an established network of engineering, sales, and service support. Tecogen is based in Waltham, Massachusetts with service centers located in nine regions of the United States. More information can be found at: www.tecogen.com.