Seattle’s 1st Passive House Apartment Building Nears Completion

A wave of multifamily Passive House development is sweeping across North America, and Seattle is about to get its feet wet. Pax Futura, Seattle’s first Passive House multifamily building, will wrap up construction this summer in the Columbia City neighborhood.

It’s about time that this wave reached Seattle; other cities have been surfing it for a couple years already. The City of Vancouver (BC) has 60 multifamily Passive House buildings under development right now, with over 1,600 units on the way. New York City is not far behind, with projects like Cornell Tech Tower and Sendero Verde becoming the norm there. Both Vancouver and NYC see Passive House as central to their respective climate action plans and have enacted policies to support affordable Passive House development.

The wave has also reached the mid-Atlantic. In Montgomery County, Maryland, just north of Washington (DC), NK is co-designing one of the largest Passive House communities in the country, with a Passive House tower and mid-rise structure slated to house hundreds of families. In Pittsburgh, we co-designed (with Thoughtful Balance) two major Passive House retrofits of abandoned schools to provide affordable housing to seniors: Morningside Crossing and Glassport Retirement Residence. Pittsburgh is already nearing the half-million square foot mark in Passive House development, thanks in part to a Pennsylvania Housing Finance Agency policy that encourages Passive House design and construction in affordable housing. 

Diagram of Pax Futura's key systems.

Now Seattle is waking up to this multifamily Passive House movement, and Sloan Ritchie and his firm Cascade Built are leading the way with the Pax Futura project, designed by NK. Sloan’s pioneering work with Passive House is nothing new; his own house, Park Passive, was the city’s first single family home to become Passive House-certified. 

Exterior screens on Pax Futura's western facade allow occupants to control solar gain, daylighting, and privacy.

Pax Futura’s 35 units are a mix of studios and one-bedroom units at a price point that is accessible to working people in this increasingly expensive city. Three ground floor live-work spaces and a corner 1,050 square foot retail space will help enliven the neighborhood and support local entrepreneurs. A west-facing system of movable exterior screens gives tenants control of how much passive solar energy their units receive, engaging occupants in the performance of the building and the thermal comfort, privacy, and natural daylighting of their own living environments. Interior sliding barn doors in each unit echo the look and feel of the exterior screens, reinforcing the experience of active interaction with the building. As Pax Futura residents manipulate the screens, the building’s western façade will be in constant flux, both in appearance and functionality. 

Sloan Ritchie welcomes Public Counsel tour group to Pax Futura construction site.

Pax Futura’s trailblazing position in Seattle’s built environment is gaining attention. Cascade Built and NK’s latest guided tour of the Pax Futura construction site took place just last week when the Public Counsel’s office of Washington State’s Attorney General visited. Charged with representing citizens in the state’s interaction with investor-owned utilities like Puget Sound Energy, the tour-goers were especially interested in the role that ultra-efficient buildings like Pax Futura can play in the clean energy transition.

Public Counsel tour group inside Pax Futura, joined by NK's Joe Giampietro (far right), Cascade Built's Sloan Ritchie (3rd from left, back row), and the author (far left).

We shared with the tour group that, for a small upfront investment, Pax Futura will use 50% less energy than a code-built building. Sloan pegs that investment, or “construction cost premium,” at 5% total construction cost, and expects that his team’s learning on Pax will allow him to bring that number down to about 2% on the next Passive House building he builds. That 2% figure jibes with construction budget data from Pennsylvania Housing Finance Agency (PHFA), comparing 59 proposed Passive House projects with 120 conventional ones. PHFA Passive House construction budgets averaged $171/sf while the conventional construction budgets averaged $168/sf: less than a 2% cost delta.

The reason that the first-cost of Passive House construction is so low for these projects is that it is relatively easy to achieve Passive House performance in apartment buildings and other mid- to large-scale buildings. Passive House requires an investment in an advanced building envelope – walls, roof, and foundation – to minimize energy loss from the building. Because larger buildings have less building envelope per square foot of floor area than smaller buildings, like single family homes, it’s cheaper on a square foot basis to build a Passive House envelope for an apartment building. Think of all the shared walls and floorplates between apartment units that are not exposed to the outside. While a single family home has six exterior faces that must be protected from heat loss (four walls, roof, and foundation), an apartment unit usually has just one or two.

The revolutionary energy performance and occupant experience of Passive House is affordable in apartment buildings. But don’t take our word for it. Pax Futura provides proof that Passive House “pencils” in Seattle. Stay tuned, because more are on the way.