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Zack Semke

Passive House, A “Convenient Truth” in Building Design

While the “inconvenient truth” of the climate crisis is daunting, the clean energy revolution has created “convenient” developments that hold promise for meaningful climate action. However, it is also clear that renewables alone are not enough to address the crisis. Exactly how far can renewables plus storage get us? What role must buildings play?

A member of Al Gore’s “Climate Reality Leadership Corps,” Zack will combine highlights from Gore’s latest findings with recently published policy research from Grantham Institute of London Imperial College and the journal Science about the role buildings must play in limiting global warming to below 2 degrees Celsius. The talk will report on the current state of the global clean energy transition, the magnitude of progress still necessary, and strategies for harnessing Passive House design to transform building energy performance at scale. 


Zack is Chief Marketing Officer at NK Architects, a Seattle and Pittsburgh-based architecture firm dedicated to accelerating the clean energy transition through zero carbon building design. He studied human biology, with a focus on human ecology, at Stanford University (BA, ’93). Since then he’s worked as a policy advocate for progressive regional planning, a developer and leader of nonprofit community organizations, a taiko (Japanese drum) musician, and an evangelist for Passive House construction. Zack is a regular speaker at sustainability gatherings and high performance building conferences, drawing the connection between the clean energy revolution, high performance building, and climate action. Zack serves on the Board of Directors of Passive House Northwest and co-chairs the Steering Committee of the Zero Net Carbon Building Alliance.

Medgar Marceau

Passive House and Commercial Construction: The Evolution of Residential Passive House Building Standards and the Application to Commercial Construction”

The accelerating growth of Passive House across the US and Canada is leading a change in the building envelope industry across the Pacific Northwest. With Vancouver’s new mandate to meet the Passive House standard for all city-owned commercial buildings, and Seattle’s progressively stricter energy codes, it’s only natural that our industry will have new challenges and opportunities to meet on the path to sustainability.

There is a large knowledge base of how to build durable residential buildings that meet the Passive House standard; however, there are few examples of commercial buildings meeting Passive House. This presentation will help bridge the knowledge gap between residential and commercial construction. Basic principles of Passive House are high levels of insulation, no thermal bridging, an airtight building, very high-performance windows and doors, heat and moisture recovery ventilation, and optimizing solar heat gains. All of this while ensuring occupant comfort and durability are paramount. Achieving these objective in Passive Commercial will require the same.

This presentation will discuss:

  • Acknowledging the challenges in translating Passive House to Passive Commercial
  • Solutions for minimizing thermal bridging in commercial construction
  • Solutions for an air-tight interior vapor retarder
  • Thermally efficient at-grade and below-grade transitions
  • Using 2-D and 3-D simulation tools to evaluate hygrothermal performance
  • Impact of 3-D Passive House Envelope Details on whole-building energy use


Medgar is a principal and senior building science engineer at Morrison Hershfield with 19 years of experience in the areas of building science, energy codes, and environmental life cycle assessment. His experience includes building envelope design and review, hygrothermal modeling, environmental life cycle assessment of concrete and concrete structures, whole-building energy simulation, public speaking on energy codes, and performing envelope trade-off calculations for energy code. He received his bachelor of science in engineering from the University of New Brunswick and master's degrees in applied science from Concordia University and applied mathematics from DePaul University. He is a licensed professional engineer. His passion for sustainability started with his post-graduate work, where he studied the effects of occupant behavior on energy use in buildings, and he has taken on the challenging sustainability goals that Passive House presents. Medgar has presented many times throughout the region for AIA and the Northwest Energy Efficiency Council, and he has authored papers on thermal performance and energy modeling of the building envelope.