11 Crown – Passive House Development
The 11 Crown development includes a four-story multifamily building with 63 affordable housing units; amenity, office, and retail spaces; and an attached parking garage. Two additional buildings ascend the steep slope of the site and contain 18 three-story townhouses. All buildings were designed to the Passive House standard.
The four-story building meets Passive House requirements with less insulation than the townhomes due to higher density and internal heat gains. The other buildings have a greater exterior surface-area-to-volume ratio and a lower density of occupants, appliances, and plug loads, resulting in fewer beneficial internal gains in the winter. The four-story multifamily building achieved certification under the PHIUS+ program, while the remaining two buildings fell short only under the strict Passive House requirements for air infiltration testing.
Each residential unit is provided heating and cooling from ducted, air-source heat pumps; hot water from natural gas, tankless heaters; and ventilation from in-unit Zehnder energy recovery ventilators (ERVs). Challenges with the verification process included testing the ERVs where intake and exhaust was only accessible on the building’s exterior.
SWA was recruited by Kenneth Boroson Architects to join the project team and provide energy modeling and Passive House certification consulting. SWA also provided final testing and verification for the certification and labeling programs. The firm has enjoyed a comradery with the project team despite COVID-19 and typical construction challenges.