I just sat thru a webinar sponsored by The ACHR News (magazine) and BPI that gave a pretty good high level overview of why HVAC contractors should consider getting into home performance contracting.
The slides from it are here: The Business of HPC.
The actual broadcast will be available in a few days at this LINK look under the 9-19-12 webinar listing:
Crushing Your Competition As A Whole House Home Performance Contractor