http://www.southface.org
Southface promotes sustainable homes, workplaces and communities through education, research, advocacy and technical assistance.

http://www.natresnet.org
Resnet - improving the energy efficiency of the nation's housing stock.

http://www.energystar.gov
ENERGY STAR is a government-backed program helping businesses and individuals protect the environment through superior energy efficiency.

http://www.energysvc.com
This company is involved with ENERGY STAR,  as well as testing and upgrading existing homes in Delaware, parts of South Jersey, and Maryland for about 25 years. They are considered to be one of the leading authorities for energy management on the east coast.