Simon Hare, a builder and design consultant based in the Roxbury section of Boston, decided to apply basic Passivhaus precepts, rather than the technical, detailed modeling often deployed for Passivhaus projects, to the reconstruction of a house in his neighborhood.
The scale and legal disposition of the building, known as the Pratt House, also mesh well with Hare’s goal of building a house that, even without renewable-energy sources, will be highly efficient. For the purpose of addressing flaws in airtightness and thermal resistance, for example, it helps that the house is only 750 sq. ft. – about 6% smaller than most entries in the Department of Energy’s Solar Decathlon. And for the purpose of seeing the project through on Hare’s own terms, it also helps that the house is owned by his family.
Discussing his approach to the project for a story by CNET News.com, Hare said he hopes the project will show that construction of near-net-zero-energy homes is within reach of everyday building professionals.
“The Passivhaus approach is very techie, which I think is its Achilles’ heel – it appeals to geeks but not the layman, the lay builder,” Hare told CNET News. “We can prove we can do this without hiring consultants and using software to do the energy modeling. We’ll just use precedent and established rules of thumb.”
The exterior walls feature structural insulated panels – in this case 12 in. foam cores sandwiched between plywood sheets – and a 1-in. layer of rigid insulation on the exterior-wall surfaces, which Hare says bring the walls to R-50. All joints were taped or sprayed with foam.
Hare and his company, Placetailor, hope to finish the project by the end of October, as the house nears one of the ultimate tests of energy efficiency – the Boston winter.