Threshold Builders' panels are set on the jobsite.
Sean Ritchey Threshold Builders' panels are set on the jobsite.

These days, it’s not uncommon for builders to construct homes from panels. They provide an attractive combination of customization, factory quality control, and reduced construction time—at a point when the industry is facing a nationwide shortage of skilled labor. All these benefits make panelization ideal for building Passive House homes, which are technically sophisticated and require more precise construction. (Click here for more about recent developments in passive building.)

Panelized Passive House systems are fairly new, but builders say the approach pays off. “Our airtightness numbers have dramatically improved since we’ve moved to panelization,” says Sean Ritchey of Kingston, N.Y.–based Threshold Builders. “The shop lends itself to better quality control than a construction site, since we’re designing the whole building as a system. But you have to invest in the facilities and equipment like framing tables to switch to an off-site construction set-up, which is pretty expensive.”

Another option is to outsource the panels from a company like Bensonwood, which specializes in panelized timber-framed buildings and has a 110,000-square-foot factory in Keene, N.H. It recently launched its PHlex panels for architects and builders.

“It’s intended to be a flexible system, designed around the idea that Passive House is a performance metric—it’s not just ‘20 in the foundation, 40 in the wall, 60 in the roof,’” says Rheannon DeMond, a certified Passive House consultant at Bensonwood, referencing a home’s R-values. “It can adapt to the amount of glazing, the climate zone, or whether it’s a residence or multifamily or commercial building.”

The company’s wall, floor, and roof panels are shipped to the site with pre-installed doors and windows; Bensonwood sends out a supervisor to help a local construction crew assemble the weatherproof, airtight building shell.

Perhaps the one downside to panelization is that it is much more difficult to fix a mistake. “If you have a window in the wrong place, it’s typically going to be discovered when there’s a more complete assembly already,” says Ritchey. “That’s where super-meticulous planning is such a critical part of the approach, which is true for Passive House in general.”