Mystic — Courtney and Lynn McCracken had spent two or three years looking for land on which to build their dream house.

The struggle came from their desire for a piece of land that is flat, able to accommodate a south-facing house, in their price range, near I-95, near the water and closer to their daughter in New Jersey than their Rhode Island residence.

Courtney McCracken was talking to a co-worker at Brown University, where he works in facilities management, who lives in Mystic. That co-worker has a cycling friend who owned the property the McCrackens ended up buying in Mystic.

They bought the 4-acre property in 2015, enlisted Groton-based Mercer Bertsche Vernott Architects, began construction with builder Michael Joplin in October 2016, and moved in last June.

Eversource and United Illuminating recently named their 119 Fishtown Road home as the overall winner for the eighth annual Energize Connecticut Zero Energy Challenge. Out of seven homes built in 2017 and 2018, it had the lowest HERS Index, or Home Energy Rating System score.

Sitting in his home recently, Courtney McCracken, along with architects Chris Vernott and Bob Mercer, talked about the design/build process and what makes the house so energy-efficient.

For those concerned with energy efficiency, the goal is to have a HERS Index of as close to zero as possible, meaning the house produces the same amount of energy it uses. A house built before the 1990s scores about 130, a newer home about 100 and an Energy Star home from 77 to 85.

The McCrackens' house has a score of -22, which would be considered cost-ineffective, except that Lynn McCracken uses the excess solar energy to charge her Chevrolet Volt.

Atop the 2,050-square-foot house are 36 solar panels, for a total of 10 kilowatts. The walls are insulated with 12 inches of dense-packed cellulose made from recycled newspaper.

The house is so airtight, it requires very little heating or cooling, Courtney McCracken said. The couple has one mini-split heat pump downstairs and one upstairs.

"You invest more in insulation and windows so that you can scale back on your heating and air-conditioning system," Vernott explained, adding, "Your house is like a thermos."

In an upstairs guest bedroom is a heat recovery ventilator, which pulls in outside air to distribute fresh air indoors.

The well-insulated house is so quiet that Lynn McCracken couldn't hear her husband using the snowblower outside one morning.

The tradeoff was that when Joplin and his team began construction, they needed to take down 22 trees, so the panels would have an open sky from which to absorb energy. Vernott said he recycled some of the trees, milling them into lumber.

The McCrackens first talked about building a home together 46 years ago, when they were students at Attleboro High School in Massachusetts and went on their first date.

Courtney McCracken became interested in energy efficiency about 10 years ago, with some classes he took at Brown.

"You just kind of catch the bug after a while, I think," he said. "It just kind of makes sense when you read about climate change and air pollution and water pollution."

He started going to Northeast Sustainable Energy Association conferences. On Aug. 3, NESEA is giving a tour of the Fishtown Road home, which Courtney McCracken expects to attract people from all over New England.

"Courtney wanted to use this as a tool to do public outreach and teach people this isn't that hard to do; it can be done," Vernott said.

The McCrackens lived in Providence from about 2000 to 2015, and then sold the house to have enough money to build the new one. For two years, they lived in the parsonage at Arnold Mills United Methodist Church, where Lynn McCracken is the pastor.

e.moser@theday.com