Sitka Apartments

Seattle, WA

This LEED Platinum® residence provides a relaxing urban oasis that weds modern design to the beauty of the natural environment

  • Rooftop community garden and vegetated roof areas
  • Indoor/outdoor entertainment zones
  • Greywater harvesting system
  • Ultra-low-flow toilets and fixtures installed in all spaces
  • Wastewater heat recovery system
  • On track to attain ambitious local 2030 targets
  • Winner: 2022 World Silver FIABCI International Real Estate Federation World Prix d’Excellence Awards- Residential Low Rise

  • Winner: Washington Chapter of the American Society of Landscape Architects (WASLA) 2022 Professional Award-Honor Award, Residential Design

  • Winner: U.S. Green Building Council® LEED® for Homes Award for Outstanding Multifamily Project

O’Brien360 was the LEED for Homes consultant on the Sitka Apartments project in Seattle’s South Lake Union neighborhood. The 500,625 square feet, seven-story 384-unit, full-block mixed-use building has unique entrances at every street frontage, representing an environmental characteristic of the Northwest—mountains, meadows, forests, and waterways—which act as passageways into the tree-filled courtyard for both residents and the public.

The project’s rooftop community garden, vegetated roof areas, and indoor/outdoor entertainment zones were designed to connect residents to the environment. The concept of nature in the city is most clearly expressed in the property’s interior courtyard, which features a running stream, tree-covered hilltops nestled between rock walls, and an imaginative take on a treehouse.

The project also utilizes a greywater harvesting system, a water recycling method that diverts water from showers and laundry for on-site irrigation.  Ultra-low-flow toilets (0.8 gpf) are installed in all spaces, along with other low-flow fixtures.  The “Swale on Yale” is a public-private project built in conjunction with Sitka, which allows the city of Seattle owned block-long biofiltration swales to collect and treat stormwater runoff from a neighboring district. The project also achieved Salmon Safe certification for practices during construction and design elements on the project.


Throughout the design process, the project team explored various opportunities to modify the design to reduce energy consumption and improve energy performance. The team made several modifications, including increasing access to natural light, utilizing exterior elevators and walkways, and including highly visible stairs.

Sitka’s energy-efficient design is a crucial focus since hot water represents the largest energy use demand in new multifamily buildings.  The wastewater heat recovery system utilizes water-to-water heat pumps to capture heat from one day’s outgoing wastewater to preheat the next day’s hot water supply, effectively recycling heat within the domestic water heating system.  A secondary design focus emphasizes heating and cooling.  Ductless heat pumps were installed in all units facing west and south, as well as about a third of the remaining units, providing high-efficiency cooling in the summer and reducing heating electricity consumption by a factor of three. These energy efficiency measures, along with others, have Sitka on track to attain ambitious local 2030 targets, including significant reductions in water and energy use, $100K/year savings divided between owner and tenants, nearly 80 tons of CO2/year eliminated, and Energy Utilization Intensity (EUI) of 16 kBtu/sq. ft./year.