I started performing home energy audits one year ago at the utility I work for. Prior to that our utility did not offer audits, even though the natural gas provider in our town does. The gas provider does "free" audits through a third-party contractor whose personnel are very qualified, but their free audit does not include thermography or blower door testing.
When we decided to begin offering audits, we decided that we would NOT offer them for free, and that we would use thermography and blower door testing to do a more complete assessment. Under our model, we charge the customer $100 for the audit, but we give them the opportunity to receive a refund of that fee IF they take actions on the recommendations in the audit report. We only performed around 30 audits last year (year 1), but about 2/3rds of the customers actually implemented the recommendations and receive a refund of the audit fee.
The reason many utilities offer "free" or reduced cost audits is because they are an effective way to identify energy savings, and almost all utilities are under mandates to use energy efficiency to reduce consumption. Obviously doing an audit does not mean any energy savings...that only comes from homeowner action. That's why we charge for them, but dangle the "carrot" of a refund.
In our case, we tried to identify a certified home energy professional or firm that could perform the audits on our behalf (for pay, of course), but there weren't any that were interested, so we decided to do it ourselves.