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Hamilton, Wenham program uses thermal imaging to show home energy loss

Owen Boesch (left) and his brother Innes rake leaves outside their Hamilton home, which was part of a pilot thermal-imaging program. Owen Boesch (left) and his brother Innes rake leaves outside their Hamilton home, which was part of a pilot thermal-imaging program. (John Blanding/Globe Staff)
By David Rattigan
Globe Correspondent / November 3, 2011

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HAMILTON - Anne Brady could tell from the cold drafts in winter that some parts of her 150-year-old house were not energy-efficient. Then she saw the pictures.

“It surprised me a little bit,’’ she said of the thermal image that put a splash of color on the areas where heat was escaping. That confirmed her suspicions about the need for some new insulation and windows, and also revealed some other areas that were energy-inefficient.

“It’s an effective way of showing what you need to do,’’ said Brady, whose Hamilton house was one of 2,000 in Hamilton and Wenham that were included in a pilot program featuring ground-level energy surveys using thermal imaging.

In early April, a technician from Woburn-based Sagewell Inc. drove a vehicle equipped with imaging cameras through streets in the two towns, capturing thermal images of buildings (mostly homes) on both sides of the street. The images show heat loss through color variation, to identify those houses that are the best candidates for energy improvements.

“What we do is drive around with a thermometer on our cars, and take the temperature as we pass by these things,’’ said Sagewell’s president and chief executive, Pasi Miettinen, who said that description comes from his 5-year-old daughter.

While similar projects throughout the United States have used images shot from the sky, the ground-level shots are something new. Miettinen said this method provides a better angle, and that it enables him to collect information quickly.

In Massachusetts, there are about 30,000 energy assessments in a year, Miettinen said. “In an urban setting, I can get 30,000 buildings in two days.’’

Funded by a $213,774 federal grant administrated by the state’s Department of Environmental Resources, the project included Hamilton, Wenham, Lexington, Arlington, and Greenfield. (Another study included seven towns in the Springfield area.)

There was no charge to residents for the thermal imaging, and no charge for those who followed up with nonprofit Mass Save for a home energy assessment. Residents are under no obligation to follow up. They pay nothing to Sagewell, which receives additional funding from energy service providers that are listed on its website. It does not sell homeowner contact information, according to Miettinen.

Hamilton-Wenham was the first to release the results, at a public presentation Oct. 1. From a list of 1,000 homes, Sagewell sent out postcards to owners of 200 it judged to be the least energy-efficient, and therefore most likely to benefit from an energy assessment and retrofit, which could include adding insulation, air sealing, and/or new windows. Other residents were encouraged to check the company’s website to see if their home had been surveyed. “Two things about this are most important,’’ said Hamilton selectman Dave Carey, who championed the project. “Number one, it ranks them [in different priority categories]. Number two, because homeowners can look at the image, they get enthusiastic. They can see it as an opportunity, and not just as an abstraction.’’

A privacy-protected Sagewell website ( page allowed homeowners to see the thermal image of their own home, and to click through to a page that provided information on how to have an energy assessment done, and other remediation options.

According to Miettinen, within four days about 100 homeowners had logged on and were in the process of scheduling an energy assessment from the Sagewell site. Ten percent is much higher than average for an energy-efficiency program, he said.

“It’s very exciting,’’ said Sue Patrolia, sustainability coordinator for Hamilton and Wenham as well as a volunteer for Hamilton Wenham Green, the community group that worked with Sagewell on the project. “The fact that there were so many hits on the first few days is overwhelming.’’

With a project goal of capturing 1,000 thermal images in Hamilton and Wenham, the company took images of approximately 2,000 houses. Distance from the road or obstructions such as bushes or fences prevented clear images of every house, but the company was able to plot about 1,500 structures.

Because of the strong response when news of the first 1,000 images was released, Sagewell then provided the information it had for the owners of the remaining 500 homes, including a plan to send postcards to the 20 percent of those that were least energy-efficient.

Miettinen also said his company will return during the winter to take thermal images of the structures in the two towns that they didn’t shoot last spring.

“In the long term, I’m sure it will benefit us, but right now we’re simply doing it for the good will it will bring to us,’’ Miettinen said.

Brady, her husband, and their two children, who live on Gifford Road in Hamilton, try to live a “green’’ life, mindful of conserving resources. Part of that will now include remediation of the energy-inefficiency issues in their home, Brady said.

“The thermal imaging was a real kick in the pants to get us going on this, instead of just thinking about it,’’ she said. “Here was evidence that this is absolutely necessary.’’