Certified green home offers big paybacks

Whitefish Pilot

A new home in Whitefish recently became the second residence in Montana to achieve gold-certification by the National Association of Home Builders for its energy-saving features.

Mark Van Everen, of Bridgewater Innovative Builders, built the hybrid timber-frame house on Pine Avenue as a model for his construction company and a home for his family.

Sam Hall and Zandy Sievers, of Sustainable Building Systems, drove up from Missoula to inspect the house. The company tests buildings across Montana to see if they qualify for certification for Energy Star, federal and state tax credits, and Leadership in Energy and Environmental Design (LEED).

Van Everen's home is not a LEED home, but it's 'super tight," Hall said.

"This house is unusually tight, so we're having trouble with our test equipment," Hall said. "He's doing great so far."

In the "duct blaster" test, Hall and Sievers used a fan to pressurize the duct work throughout the house to check for leakage. The "blower door" test creates a vacuum in the house to see how much infiltration exists.

"A super-tight house has about 0.07 air changes per hour under the blower-door test," Hall said. "Typical houses see about 0.4 air changes per hour."

With so little outside air entering the house, amounts of carbon dioxide and indoor pollutants released by synthetic building materials can reach hazardous levels. To bring in fresh outside air without losing energy efficiency, Van Everen installed a central heat-recovery ventilation unit in the basement. The unit uses a heat-exchanger to heat fresh outdoor air with exhaust air piped in from the house's 2 1/2 baths.

Van Everen also installed a groundsource heat pump system for heating and cooling the house and boosting the electric hot water heater.

Five six-inch diameter pipes run 160 feet down below his backyard in to deep ground where temperatures remain relatively constant in winter and summer. The temperature differential between hot ground and cold surface is used to heat the house in winter, and the differential between cold ground and hot surface is used to cool the house in summer. A network of tubing filled with methanol transfers the heat.

"About a month ago, the methanol was coming in at about 46 degrees and going out at about 41 degrees," Van Everen explained. "That five-degree difference was enough to heat the house."

The glacial till soil commonly found in Whitefish is tight, like the house, and holds heat well, Van Everen said. It's also a good idea to run the air conditioning in the summer to put heat back into the ground below the house, ready for next winter, he said.

Van Everen, who built active-solar homes in Colorado before moving here two years ago, employed numerous energy-saving measures throughout the 2,650-square-foot house, from compact fluorescent bulbs to insulated concrete forms in the basement.

The 2-by-6 stud frame is spaced on 24-inch centers and filled with blanket insulation. Continuous rigid insulation is installed on the exterior, and 3/4-inch foil-faced rigid insulation is on the interior. The cathedral ceilings are insulated with R-40 stressed-skin foam panels with few seams.

"In building an energy-efficient home, you need to start with the basics — good insulation and good construction — and then look at high-tech things like active solar and groundsource heating," he said.

Pieces of the 700-square-foot house that formerly sat on the lot have been recycled for the new home. Whitman Brothers Manufacturing, of Columbia Falls, milled the floor joists into bead-board paneling and flooring for the kitchen area, the floor boards were turned into shelving, and four of the doors will be re-used for the bedroom closets.

Van Everen is looking at a wide range of financial benefits for his effort. The groundsource system alone qualifies him for a $3,000 rebate check from Flathead Electric Cooperative, a $20,000 deduction on his state property tax assessment and a federal income tax deduction equal to about 30 percent of the cost of the system, among others.

His goal is to bring annual heating costs down from $2,000 to about $350. He estimates green elements add about 6-10 percent to construction costs, but the groundsource system will pay itself back in about five years.

"And that doesn't include all the rebates," he said.