A Tennessee Family Building a Net Zero Ready Modern Farmhouse for the Generations

John and his wife Angela, who have five children (one is an adult with their own family), also wanted to build a new house that would accommodate everyone. "We want them to come home and stay without putting any of our other children out of their rooms," Angela explains. "In the long term, when we're empty-nesters, we still wanted a home that could accommodate our large family, with everything we need on the main level so we can age-in-place."  

The Plunketts read Rise Editor-at-Large, Melissa Rappaport Schifman's book, Building a Sustainable Home: Practical Green Design Choices for Your Health, Wealth, and Soul, and decided not to go the LEED route. "The book helped us a lot," Angela says. "From the book, we figured out we'd rather build a Passive House than a LEED home, and that led us to an architect who knew what we were talking about."

The Plunketts' 4,018-square-foot home, with a 700-square-foot bonus room above the garage (Angela's office for her sustainable and eco-friendly yarn business), is nearly complete. The home is net-zero ready and meets the requirements of a Passive House. "The house is ready for solar, and we have the solar panels, but we want to see the energy draw of the house before we spend the money on the installation," Angela says. 

In Eagleville, Tennessee, the home was designed by architect Ryan Thewes of Nashville and constructed by Hedgewood Builders. "Our builder was on board with energy efficiency—that's why we hired him over the seven we interviewed," says Angela. The builder's subcontractors, however, "had to be educated to think outside the box." Nonetheless, adds John, "We feel like we've accomplished that."

"Because the house we've built has thicker walls than in a traditional home—eight-inch and six-inch thick walls—traditional insulation doesn't fit that profile as well as BIBS," John explains. BIBS insulation is "blown into every cavity of the framing, and held into place with netting," he adds. "The insulation is densely packed in." 

The double-layer roof uses the ZIP System, with a two-inch insulation layer, airspace, decking, and roofing. The team extended the ZIP beyond the walls to the roof for a continuous sheath. "As the sun hits the roof," John explains, "the two inches of insulation will deflect some of the heat, which will dissipate via the two-inch air gap."

ZIP and ZIP tape covers all sides of the framing. The house is clad in concrete fiberboard, which was painted black. The first blower-door test reached about 1.3. "We are working to lower it," Angela says. "We put dollars and effort into the build to, hopefully, not need the solar panels unless we want to go all the way to net-zero. With the solar, we will meet net-zero." 

Using the BIBS and ZIP system "were a little more expensive than we initially expect," John adds, "but they provide an efficient way to get a tight envelope around the house. The home's Pella Impervia windows are made from durable, five-layer fiberglass material.

While the house isn't in a flood plain, the team built up the foundation a few feet by putting a wall of concrete blocks on top of our poured concrete footers before adding the concrete foundation.

Note from the Editor: Stay tuned...we are excited to share the finished product with you soon!