The American Council for an Energy-Efficient Economy (ACEEE) is a non-profit organization that seeks to advance energy efficiencies, programs and technologies. Offers research reports on energy efficient real estate.

A non-profit organization that seeks to promote walkable, mixed-use neighborhood development and sustainable communities. Website features research reports on these topics.

This site provides up-to-date information on green power providers, product offerings, consumer protection issues, and policies affecting green power markets. Information on green power product offerings is available by state, is organized according to the three distinct markets for green power, and supplies information on purchasing renewable power at the consumer level.

The U.S. Green Building Council is responsible for providing the LEED certification and education on sustainable building and design. Of particular interest to realtors may be organizational directories, certification resources, building calculators, and rating system resources.

A program of the National Institute of Building Sciences, this website information on a wide range of building-related guidance, criteria and technology from a 'whole buildings' perspective. The "Tools" resources is especially helpful, providing on information on topics ranging from code compliance to cost-estimating.