Dan Whitmore of Blackbird Builders is using a “Larsen truss” detail in this Passive House he is building in Seattle for his family. The 14" wall cavity will be insulated with dense-pack fiberglass to achieve approximately R-55.
I’m old enough to remember the passive-solar and superinsulation movements in the late 1970s. In 1976, I was involved with passive solar design while at college, where a group of us studied energy self-sufficiency, and in 1978 I moved to Santa Fe to work with the New Mexico Solar Energy Association, which was leading the charge in advancing passive solar energy.
While lower oil prices in North America erased much of our interest in these ideas during the 1980s, by then these concepts had migrated to Europe, where high energy taxes were keeping interest in alternatives high. Now the ideas of passive solar and superinsulation are back—in a much smarter way—with the Passive House movement.