A Passivhaus building in Vermont and a “green home that doesn’t look like a green home” were among the projects that won first-place PRISM Awards this year from the Builders and Remodelers Association of Greater Boston.

A four-bedroom home in Weston, Mass., built by Kingsbury Homes Limited, won the gold award for the most innovative single-family green design.

The best energy efficient project was a Passivhaus-certified home in Norwich, Vermont. ZeroEnergy Design, provided design and Passivhaus consulting for the project. Bensonwood provided building panels and construction for the house. Paul Bilgen was the consulting architect.

PRISM Awards are made in a number of building and marketing cateogies (the acronym stands for Prestigious Results in Sales and Marketing). A full list of award winners is posted at the association’s web site.

It’s even bigger than it looks

Kingsbury’s entry is a spec-built home with four bedrooms and four baths on the upper level, two half-baths on the first floor and another full bath in the basement. The house measures 4,200 sq. ft., with an additional 1,500 sq. ft. of finished space in the basement.

“At 86 ft. long, this rambling stretched-out cape is not the usual compact rectangular design typically found in a super insulated home,” an online description of the project says.

Kingsbury’s Franz J. Burke says the idea was to build a “green home that doesn’t look like a green home.” It was designed by Keith Gross of HDS Architecture of Cambridge, Mass.

Features include double-stud wall construction, insulated to R-40 with open-cell polyurethane foam, and a foam-insulated R-60 roof. The basement walls and slab are insulated to R-20. The house has triple-glazed windows, a heat recovery ventilator, and a high-efficiency gas furnace. Air leakage was tested at 0.97 air changes per hour at a pressure difference of 50 pascals (ach50).

Burke says the house has a HERS Index of 37 and a heat load of 35,000 Btu/hr.

Burke is a former bank appraiser who has been building houses only since 2006. The Weston house, his sixth or seventh project, was built on spec and later sold for $1.94 million.

Passivhaus-certified in Vermont

The winner in the energy efficient category has already received a good bit of attention, including an article by GBA’s Richard Defendorf posted in 2010.

As described at the time, the three-bedroom, 2 1/2-bath house was designed with R-60 above-grade walls, a roof insulated to R-87 and R-36 basement walls. The slab was insulated to R-75. The 2,700-sq. ft. house has been certified by the Passive House Institute U.S. (PHIUS) and was constructed on a 100-acre farmstead.

Air leakage was measured at a very low 0.49 ach50. The house has triple-glazed windows, a wood-burning stove and electric radiant floors in the bathrooms. It has a solar hot water system and, adds ZeroEnergy Design, would be net-zero energy with the addition of a 3.5 kW photovoltaic array.

In addition to its energy features, the house has non-toxic and no-VOC paints, adhesives and finishes, and a heat recovery ventilator.

Panels were built off site by Bensonwood, trucked to the lot and moved into place by crane, making a weather-tight shell very quickly. Estes and Gallup was the general contractor.