A Home in a Class by Itself
A New Hampshire lake house is one of only thirty-six homes nationwide to earn top green certification from the National Association of Home Builders.
You've heard the old adage: the grass is always greener on the other side of the fence. But if you want to achieve the highest standard for green construction awarded by the National Association of Home Builders (NAHB), you'll quickly learn that a grass lawn isn't "green" at all.
Landscaping does not spring to mind when most people think of green homebuilding. "When people think green, they think energy efficiency," says Liam Cargill, vice president of Cargill Construction in Campton. "But there's much more to it." On the shore of Lake Kanasatka in Moultonborough, Cargill Construction staff built New Hampshire's first NAHB-certified "Emerald" home.
"To earn Emerald status," says Anne Holtz Schmick, director of communications for the NAHB Research Center, "you have to achieve a high score in these six categories." They are lot design and development (including landscaping); resource efficiency; energy efficiency; water efficiency; indoor environmental quality; and operation and maintenance. The Research Center is the independent arm of NAHB that developed the green certification.
The breadth of the categories often comes as a surprise to homeowners considering green certification. But building a truly green home is as much about the process of construction as it is about the finished product. Recycling is one example. Materials that don't make it on to the house-scrap asphalt, cardboard cartons and cut pieces of wallboard-are just as important to NAHB standards as those that do.
"The old way of doing things was to put a big DumpsterTM on the worksite and throw everything in," says Cargill. But for a green home, each type of scrap gets its own Dumpster, and then each is recycled. "Very little ends up in the landfill," he says.
The old and the new uses
The Kanasatka house was built on the site of an older house, which Cargill Construction staff demolished. But before the demolition, Cargill invited a church group to come salvage fixtures and appliances for charitable works.
"I once donated a boiler to a prison," Cargill recalls. Even the concrete from the Kanasatka demolition was ground up and used to make clean fill.
"It didn't take very long to get our construction crew to understand the new way of doing things," Cargill says. Ideally, he says, the practice will catch on with all builders, regardless whether a green certification is sought. "I hope it happens," Cargill says. "Adopting these practices quickly becomes a habit."
The use of recycled and sustainably harvested materials in a new house earns points toward a green NAHB certification. Cargill used AdvanTech® composite wood for the subfloor decking and sheathing. Not only is the material durable, it is made from little pieces of wood-even scrap-to help protect old-growth forests.
Low-voltage lighting, used in the kitchen and throughout the house, helps save energy costs.
Where new lumber is used, it is chosen carefully. The framing studs and flooring were made of FSC (Forest Stewardship Council) wood harvested within three hundred miles of the building site.
"It's not difficult to find beautiful local materials," says Cargill, "like hickory from New England, instead of Douglas fir from Oregon." Even the AdvanTech sheathing is from nearby Easton, Maine.
The Lake Kanasatka home contains twenty-two different local or recycled products. In the basement, an arts and crafts room for children was furnished with cabinetry that came from another teardown project in New Hampshire. When builders are committed to re-use and recycling, every room in the house offers an opportunity for resource efficiency.
Energy efficiency counts
Then, of course, there's energy efficiency- the touchstone of green construction. The Kanasatka home, with its state-of-the-art hybrid geothermal heating and cooling system, does not disappoint.
The geothermal system takes advantage of the earth's naturally steady below-ground temperature, between 50°F and 60°F year-round. Water at that temperature is pumped from underground. An electrical heat pump exchanges heat with the water, cooling or heating the home depending on whether outdoor air temperatures are cold or hot. Because of our naturally cold climate, the Kanasatka home's geothermal system is boosted by a propane furnace when the outside temperature dips below 18°F. Heated and cooled air is delivered to the living spaces via standard forced-air ducts.
Philip Bennett, the home's architect at Christopher P. Williams Architects, PLLC in Meredith, notes that "geothermal units are potentially three times as efficient as a traditional boiler." As a bonus, the two systems-geothermal and propane-are redundant. If one should experience a mechanical failure, the other can warm the house when needed.
Of course, a heating system is only as efficient as the home's thermal envelope. The Kanasatka home has highquality Andersen® "A" series windows, which prevent drafts. And good insulation is crucial. Cargill Construction used a blown-in blanket system (BIBS) of densely packed cellulose in the walls and ceiling. The ceiling also has ridge StyrofoamTM against the rafters. To further save electricity, low-voltage lighting was used throughout.
"Currently, there are just thirty-six Emerald level homes in the country," Schmick says. More than two thousand homes have been certified by the NAHB Research Center, most at bronze, silver or gold status. "Each higher level of certification requires more forethought by both the homeowner and the builder," she says.
"It is very gratifying," Bennett says, "to see this home recognized as a good example of what can be achieved in environmental performance without sacrificing architectural goals."
Yet most homeowners will want to know-is it more expensive? The answer is yes and no. High-quality win- dows and insulation cost more than low-quality products. But homeowners save money over time on heating and maintenance.
Even the process-oriented criteria can generate savings. "You want the builder you're working with to order just the right number of shingles," Schmick points out. A tight rein against waste is good for the pocketbook as well as the landfill. Saving this sort of "green" is always welcome.