Bruce Torrey held up a chunk of fiberglass insulation that he'd just ripped from a crawl space off the third floor of Madeline Krauss and Paul Friedberg's soon-to-be-renovated Shingle-style home. Turning it over, he showed Maddy the dirty black streaks that coated its edge. "Wow, what is that?" she asked with concern. "Was there a fire?"
Thankfully, the house—the site of This Old House TV's 2007 project house—hadn't been damaged by flames. But the ugly smudges were a warning that the three-story house could still burn its new owners—with outsized heating and cooling bills. The marks were soot streaks, caused by drafts whipping against the fiberglass insulation, which collected the dirt particles from the air. Finding such drafts is part of Torrey's job as senior building investigator for Building Diagnostics, the Cape Cod–based company the couple hired to conduct an energy audit on their house before construction began so they could learn where they needed to tighten up.
Leaks and drafts that let heat escape in the winter and trickle in during the summer aren't easily detected, because they're usually the result of problems behind walls or in other hard-to-reach places. "Heat loss and drafts are by their nature invisible," says Torrey, who worked with TOH general contractor Tom Silva to identify problems in the 1897 house. Together, they ran a diagnostic energy audit, which relies on a combination of sophisticated equipment and good old-fashioned detective work. For a cost of about $400, such an audit provides homeowners with a written report detailing a home's problem areas and laying out cost-effective solutions.