WILLIAMSTOWN -- Steve Swoap knew solar energy was in his future after he doubled the size of his family's home two and a half years ago.
The increased size of the home would lead to higher energy costs -- an expense he was eager to minimize.
So Swoap had roof-mounted solar panels installed last week on his 2,400-square-foot residence at 51 Mount Williams Drive under the Solarize Mass program.
Once the system is operational, Swoap expects within a year to benefit from the much-needed savings by leasing the solar array from the installer.
"When I have three teenagers taking long, hot showers, I knew the time was right," said Swoap, a biology professor at Williams College. "It was a financial decision, but also the right thing to do."
Williamstown, along with Lee, are the two Berkshire communities currently participating in the state-sponsored solar energy program that is expected to save Massachusetts homeowners and small businesses money on their electric bills.
Swoap is among the 41 local homeowners, along with 23 in Lee, who are under contract with a Colorado company hired to install solar arrays during the latest round of Solarize Mass, which wraps at the end of this month. The Williamstown COOL (carbon dioxide lowering) Committee, a local group dedicated to reducing reliance on fossil fuels, recently conducted an open house at the Swoap residence.
Wendy Penner, chairwoman of the Williamstown COOL Committee, says the showcase was an opportunity to educate the public about residential solar energy.
"Sometimes people need to see it put on a roof, what it will look like and hear how it will work," Penner said. "As for Solarize Mass, it has exceeded are expectations by a large margin."
In Lee, Roger Scheuer, of 125 Fairview St., will display to the public his 8 kilowatt system from 10 a.m. to noon, on Sept. 28. The town's local coordinator for Solarize Mass, Scheurer purchased the solar array outright through the installer.
"The simplicity of it is impressive," he said. "If you have a roof with a lot of sun, just do it."
Also impressive is the response of Western Massachusetts compared to the seven other Massachusetts municipalities participating in the first round of Solarize Mass in 2013.
According to the Massachusetts Clean Energy Center, the state agency overseeing the program, Williamstown, Lee and Northampton account for 51 percent of the 229 contracts already signed statewide.
Home and small-business owners in communities currently taking part in Solarize Mass have until Sept. 30 to sign a contract with the designated installer. In separate bidding processes, Lee, Williamstown and Northampton chose Real Goods Solar.
Under the program, homeowners can buy a photovoltaic system outright from a state-approved installer, lease the solar panels, or have the company own and maintain the panels, with the electricity generated being sold to the homeowner at a rate lower than a utility's charge.
At the request of home and business owners, the companies complete a site assessment -- free of charge -- to determine the solar compatibility of the properties and potentially offer several financing options to pay for the solar projects.
A pilot program in 2011, Solarize Mass was expanded last year, leading to 803 private property owners in 17 Massachusetts cities and towns -- including 58 homes and businesses in Pittsfield and Lenox combined -- to sign contracts with installers by early November. For more information, visit www.coolwilliamstown.org or www. massc ec.com/solarizemass.