Bensonwood

Bensonwood has been building timber frames in Walpole, New Hampshire since 1973 and now manufactures closed-panel enclosures — walls, roofs and floors built in a factory and assembled on site in days. The idea worth knowing them for is Open-Built, developed in 1994: a house separated into six layers, from site and structure through skin, space plan and mechanical systems to the occupant's own belongings, with a service cavity on the interior face of the insulation so that wiring, plumbing and ductwork can be reached and replaced without opening the enclosure. It is a maintenance argument rather than an energy one, and it has aged better than most of the industry's marketing.

The manufacturing claims are specific enough to check: cellulose dense-packed to three pounds per cubic foot, panels fifteen inches thick, tolerances held to a sixteenth of an inch, exterior doors three and a quarter inches thick with a rigid insulation core, a double-rabbeted jamb carrying two layers of weatherstripping and a three-point locking mechanism. They also publish prices, which almost no custom builder does — a 1,528 sq ft Unity Collection house lists a shell estimate around $163,000 and a finished range of roughly $520,000 to $673,000, with a standing disclaimer about site-specific costs. And they are candid about where that leaves them: not price-competitive with stick framing built to code minimum.

The independently verified record is real but narrower than the marketing implies. At Hampshire College's R.W. Kern Center, which the International Living Future Institute's own case study lists as Living Certified under LBC 2.1, Bensonwood supplied the timber frame — the Red List materials vetting belonged to a separate consultant. Unity House, built for Unity College's president in 2008, is LEED Platinum and carries the only measured performance data across this batch of firms: over the year from October 2008 it produced 6,441 kWh and consumed 6,430 kWh. A net-zero year, metered and published by the college rather than the builder.

Two things need stating plainly. Bensonwood's Passive House position is a capability, which the company says itself, but two project pages assert a certified building. One holds PHI Low Energy Building certification, a distinct and less stringent PHI class than Passive House Classic; the other has no certification record at all. On health, the company runs two separate frameworks with different categories, its Red List language appears at two different strengths on a single page — materials are "Red List-free" in one block and "avoid materials identified on the Red List" in another — and a HEPA filtration claim appears exactly once, in a blog post, and in no product or project documentation anywhere. The enclosure engineering is the substance here. The healthy-home framework built on top of it has never been measured in a finished house.