Talk title: "Taking Passive Building to New Heights: Scaling from Single-Family Homes to Multifamily Housing"
Greta Tjeltveit's career started as a single-family energy rater and has since grown into work on large multifamily Phius (Passive House Institute US) projects. In this talk from the Westford Symposium, she compares what changes and what stays the same as passive building practices scale from single-family homes to multifamily housing: how site context and building form drive design decisions, how framing factors and wall assemblies differ between the two building types, and how occupancy density changes insulation and enclosure strategy. She also shares data from air barrier testing across a portfolio of projects, comparing interior versus exterior masking methods and what that means for real-world airtightness, and closes with a look at centralized ventilation strategies for multifamily buildings and the tradeoffs involved.