The Next Frontier in Passive House: Domestic Hot Water & Solar Electrification (Sean Armstrong)

4 Hour Afternoon Workshop • 1:00 PM – 5:00 PM • Thursday, Oct. 18


During this session, workshop leader Sean Armstrong will lead attendees in an exploration of the scale and nature of domestic hot water loads in Passive House buildings. Attendees will learn the diversity of heat pump water heaters available to help achieve complete electrification of building energy and dive into architectural considerations for the siting of these heat pumps. Sean will share guidelines for the highest-performance design and commission of these systems, illustrated with practical case studies at each scale of building: tiny homes, small homes, large homes, apartment complexes and commercial buildings. Attendees are encouraged to bring their projects for discussion and proposed design solutions!


Sean Armstrong is a leading Electrification expert in North America, speaking often in a technical capacity on Zero Net Energy generally and heat pump water heaters specifically at conferences. His firm, Redwood Energy, has led the nation in residential ZNE design since 2011 (2500+ all-electric, 100% solar powered homes). Their work won the United Nation’s 2017 Grand Prize “World Habitat Award” for solving the intractable homelessness problems of California’s farmworker families using ZNE design to close the funding gap.

Sean’s career designing ZNE affordable housing began in 1995 when he joined Humboldt State University’s academic program within a campus-based demonstration house, where students were trained to design and install solar arrays, wind turbines, batteries and a wide array of conservation retrofits. He taught high school science until switching careers in 2005 to take advantage of the opportunity to design ZNE affordable housing with a local, large developer. In 2006 the nation’s first tenant-serving PV array was deployed to 36 apartments, but costs were too high. Sean went to Sacramento and DC, successfully advocating for programs that became Virtual Net Energy legislation and enhanced solar rebates for affordable housing. In 2011 he co-founded Redwood Energy to expand on Zero Net Energy design for affordable housing with his partner Michael Winkler, an Engineer and Physicist, and together they tackle difficult electrification challenges.