Stack House Apartments

Seattle, Washington

Pioneering High-Efficiency Design Across a Full City Block in SLU

The Stack House project transformed an entire city block in Seattle’s South Lake Union neighborhood with the development of two seven-story multifamily buildings and the adaptive reuse of the historic Supply Laundry Building into modern office and retail space. Designed to meet ambitious energy goals and urban sustainability targets, the project earned LEED Platinum certification for the multifamily portion and was named LEED for Homes 2014 Multifamily Project of the Year. The Supply Laundry Building was also the first pilot project to implement Seattle’s outcome-based energy code, setting a new precedent for energy performance in historic renovations. Together, the three buildings represent a key benchmark in the city’s push toward high-efficiency, low-carbon urban redevelopment.

Ecotope provided mechanical and plumbing engineering as well as energy consulting services across the site. The largest residential building features a central heat pump water heating system using a reverse cycle chiller located in the parking garage. Approximately 40% of the apartments utilize ductless heat pumps to efficiently serve units with high solar exposure. The design also includes corridor isolation strategies to improve ventilation and energy control, along with rainwater catchment systems that support landscape irrigation and rooftop garden plots. In the Supply Laundry Building, Ecotope integrated Design For Off™ strategies to reduce plug loads and system runtimes, demonstrating how deep energy savings can be achieved even in challenging retrofit conditions.

Learn more about this project here:

• Saving History, Saving Energy. ASHRAE Journal, April 2016.
• Case Study: Stack House Apartments Surpasses Industry Standards for Sustainable Innovations and Energy Efficiency. Runberg Architecture Group, July 2017.