Like a prop out of the "Ghostbusters" movies, the screen on Flemming Lund's work gear shimmers with iridescent colors as it senses a world we cannot see.
It is an infrared camera, and Lund uses it to locate a different kind of phantom - the empty spaces and pockets of air behind poorly-insulated walls, the slits and other openings at corners, seams, and sills through which cold air infiltrates and expensive warm air escapes.
Lund is an energy auditor for Infrared Diagnostic in Sudbury, and on a dry, overcast, 40-degree morning in late October, he was called into service by Christopher Buckley, whose five-year-old, 3,000-square-foot home in Milford had dramatic temperature differences, particularly when the weather got cold. His heating bill seemed too high. Sometimes he could feel breezes in the second-floor hallway.
"I just suspected the house was not properly constructed or insulated," Buckley said.
Lund had Buckley push the heat that morning to 68 degrees, because he needed at least a 20-degree difference between the inside and outside temperatures to correctly inspect the house.
Making a full sweep of the rooms with the infrared camera, a floating dot on his liquid crystal display jumps to the seam of a living room wall and ceiling.
The blue space around it was 55 degrees - roughly 10 degrees cooler than the rest of the wall.
"There's definitely insulation in the walls and ceilings, but down at the edges . . . it wasn't done properly," Lund said. "They didn't tight it in nicely, so the air comes in."
Lund then proceeded to do a "blower door" test by affixing a fan apparatus to Buckley's front door. By depressurizing the interior and drawing air out of the house, the test helps find openings where cold air infiltrates the living space.
While the fan hummed downstairs, air that clocked in at a chilly 46 degrees could be felt streaming in from under a second-floor duct register. The downdraft, exaggerated by the pressure change, revealed the seals around the duct bleeding heat - and money - from Buckley's house.
"I'm a little bit surprised, with a new house like this, that we see it as badly," Lund said. He estimated that sealing the ducts and fixing the insulation would save Buckley $600 per year.
Buckley said he wanted to use the report to pressure his subcontractors into doing the job right.
"I guess I would love to use [Lund's] report and e-mail it to the people who did the work and say, 'Gee, are you going to get this fixed?' "
Buckley called the subcontractors who did the insulation and the ductwork. The ductwork is now fully sealed, Buckley said, and the insulation subcontractor promised him he would fix those problems, free of charge. While the report prompted action from both, the subcontractors said they did their initial work according to established codes.
The insulation contractor, Theodore Plona at Quality Insulation, of Milford, said he was more than willing to help Buckley. He's been through this before. Plona occasionally receives calls from customers who have had an infrared scan, and said sometimes the inspection reveals problems. But Plona also said that other times he felt the inspector did not correctly read the data from the infrared scan.
"Most definitely I have problems with the interpretations," added Robert Zagame Jr., the contractor who installed the ductworks at Buckley's home. The leaks, he argued, could have been caused by any number of reasons, and in any case, are unlikely to be large enough to affect Buckley's heating bill.
"Maybe the [duct sealant] cracked, or my guy missed a few spots. I can go in and seal that, but I feel that in no way is that going to change [Buckley's] heating bill, not in a way measurable in dollars to him," said Zagame. In 30 years of work, he added, Buckley's is the first call he received as a result of an infrared inspection.
The skill of the inspector is critical, said Bruce Harley, technical director at the nonprofit efficient-energy consultancy Conservation Services Group. For infrared technology to be effective and useful, he said, the inspector has to have expertise in using the equipment and interpreting the data.
"An IR camera in the hands of someone without ample experience can be a complete waste of time, either because the information is not interpreted correctly, or because identifying and specifying the solution may be the most critical part - and the IR camera doesn't tell you that," Harley said.
While a number of problems can arise during construction and inspections, Harley said, "when [homeowners] find major issues and are told the work is done to code, what they are really being told is that the work has been done to typical installation standards . . . which means neatly and continuously."
But the codes also require the sealing of leaks and ducts, Harley said. "These are the requirements that are often missed."
At minimum, Buckley's situation demonstrates how infrared technology can empower homeowners to control their energy costs.
"The inspector can now show them images on the spot," said Tom O'Toole, business development manager at infrared camera maker
Joshua Rosen's early-19th century farmhouse in Westford is a patchwork of old and new construction, including an attached post-and-beam barn, a bedroom from the 1970s, and a breakfast room from the 1990s.
"I mean, drafts are an understatement," Rosen said. "The issue with a house like this is there's no way to know, without doing something like this, whether it's got insulation or not."
Infrared thermographer Joshua Page, of Infrared Hi-Tech Solutions in Templeton, swept Rosen's house with an infrared camera in early November. From the outside, sections of wall glowed cotton-candy pink as heat radiated from the inside.
And then, inside, upstairs under the eaves, the camera found a villain: squirrels. The furry rodents had returned to his shut-off attic and shredded the fiberglass insulation. All that remained were dusty gray tufts.
"We were getting the heat loss coming out of the house at 72 degrees," Page said. "That's like leaving windows open for the whole winter."
Both Rosen and Buckley received written reports that vividly captured their homes' heat-loss problems with side-by-side images of trouble spots and their corresponding infrared signature.
Homeowners such as Rosen and Buckley can protect themselves from cold-weather surprises by ensuring that insulation and construction is sufficiently high that the home earns an Energy Star rating.
"We're always trying to educate people at all stages in the construction process - builders, tradespeople, architects, code officials, as well as clients - how important it is to adhere to basic details," Harley said. "When we do an Energy Star . . . rating, we always look at these details during the construction process and we don't issue a rating if the thermal characteristics of the home do not meet or exceed basic code standards."