I had a call from a client asking if we had a list of companies that conduct home energy audits. Though not on our company contractor list, I felt that as an Exclusive Buyer's Agent, this was something I should have readily available. I spoke with some of my old colleagues at the US Environmental Protection Agency and found the following links which may be useful to you and your clients. I asked my client to let us know if he likes the energy rater he uses so we can add them to the Buyer's Edge contractor list, but in the meantime, the first link provides certified home energy raters listed by state. The other links may be helpful to you or your clients if interested in a more self-oriented approach. If you have any experience with any of the energy raters on the list in MD, VA or DC, whether favorable or not, I'd sure appreciate hearing from you.
Directory of Home Energy Raters
http://www.natresnet.org/programs/providers/directory.aspx
Home Energy Yardstick
http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_index_tools
Home Energy Audits
http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_audits