Passive House Podcast · Matthew Cutler-Welsh, Zack Semke, Mary James, and Ilka Cassidy

282: BuildingEnergy Boston 2026 Part 2

April 8, 2026·52 min·4 clips

Melissa O'Mara and Kevin Stack led a guided meditation connecting attendees to ancestors and future generations at a packed NESEA keynote.

Future generations set the tone. The opening question asks what today's building choices mean for children, grandchildren, and great-grandchildren. Matthew brings Zach and Ilka back together, and Ilka reports from a very full second day curating sessions. The conversation feels less like a formal recap and more like colleagues comparing notes after dense days with the Passive House community. The center of the episode is one retrofit. Ilka walks through an old Acorn deck house, a prefab post-and-beam type with soaring ceilings, big glass areas, and mid-century modern appeal. That charm is also what makes the project difficult. The house was a tight kit of parts, so improving energy performance meant working around a structure that did not want to move. The scope kept shifting. A client who first considered teardown moved through a lighter-touch option before the project became a deep energy retrofit with tough architectural limits. The structural work was serious: the team had to remove main-floor structural columns and reverse the structural direction to meet the client's expectations. The envelope work brought a different problem. Four inches of rigid insulation could make the house look puffy, so the design challenge became visual as much as thermal. Zach picks up on that practical detail, and his response keeps the episode grounded in craft, building science, and plainspoken design judgment. The embodied-carbon question comes through clearly when an audience member asks whether all that intervention was still better than building new. The answer stays honest. Retrofit depends on the structure, the client, the performance target, the cost, and the carbon. The close widens again, with Ilka treating disruption as real, but also as the kind of place this community knows how to work.

As heard by us

A conference recap that follows a tough Acorn deck house retrofit and the carbon-versus-rebuild question.

The episode centers on a narrow retrofit problem: how to adapt an old Acorn deck house without flattening the character that makes it worth keeping.

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Why you'd press play

You want the retrofit-versus-rebuild question answered through a real deep-energy retrofit of an old Acorn deck house.

Read the full recommendation in PlayNext →

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