Patrick Goddard doesn't like energy audits. For him, as director of facilities for the town of Lexington, Massachusetts, an audit means a day spent walking around one of 22 buildings owned by the town, peering at insulation on windows and finding the keys to the HVAC room.

Worse, auditors "don't understand how the buildings operate," Goddard complains. "They see it at one point in time and do an analysis on what they see." Usually, their report comes back weeks later recommending more equipment, new windows, or more insulation.