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

262: Deep Dive into Deep Energy Retrofits with Kara Haggerty Wilson

November 4, 2025·53 min·4 clips

Kara Haggerty Wilson explains why her entire firm chose deep energy retrofits as their most exciting and challenging work.

Exterior work sets the tone. The cold open gets right to the problem: an exterior approach, tenants still in place, and all the practical friction that brings. Zach and Mary ease into the episode before Mary’s interview with Kara Haggerty Wilson of Onion Flats. The conversation turns to the plain, difficult mechanics of deep energy retrofits. Access matters. So does observation. So does checking each layer before anyone gets too comfortable with the plan. One example sticks. A vapor barrier can look like a helpful discovery until the team realizes it is not sealed to anything. At that point, the finding changes from reassurance to a new problem. Kara talks through the gap between documenting existing conditions and proving, during construction, what those conditions really mean. Limited access makes everything sharper. If the design period cannot fully open the building, construction starts with more investigation than anyone might want. Scope can move quickly. Assemblies that looked verified still need another look once the team can actually reach them. Continuity keeps coming back. Air, vapor, and thermal layers have to connect in the real building, not just in drawings or site notes. Unit access is still hard. Kara says teams need to walk through, photograph, and understand interiors before retrofit decisions can settle. Matterport scans help here, giving the contractor, owner, consultants, and team a way to revisit conditions without constantly entering every unit. The episode stays practical. It does not sell a magic product or shortcut. It shows how retrofit judgment gets better when teams can see more, verify earlier, and leave room for uncertainty. Mary closes warmly afterward, with conference notes and subscriber reminders wrapped around a technical but grounded interview.

As heard by us

Deep retrofits become a question of access, verification, and disciplined scope.

Kara Haggerty Wilson's conversation treats deep energy retrofits as an exercise in access, sequencing, and honesty about what is already there.

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Why you'd press play

If you need a working discussion of deep energy retrofits, start here.

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