Passive house Plus - Issue 5 (UK edition)

Park Passive, Seattle Situated in Seattle's Madison Park neighbourhood, Park Passive is the city's first certified passive house. Designed by NK Architects and constructed by Cascade Built earlier this year, the four-bedroom home uses 75-80% less energy than a house built to the state's building code.

"Passive house’s focus on performance, human comfort and simplicity aligns well with our approach to design," says Boyd Pickrell of NK Architects. "It supports our mission to create dense urban housing that is responsive to people’s needs and supportive of highly sustainable lifestyles."

The tiny site was tricky for the designers of the house, which has meaty 450mm double-stud walls and 600mm of insulation in the roof. Airtightness is provide by the internal OSB board, sealed up with Siga tapes. Triple-glazed Intus windows were imported from Lithuania.

The home’s vaulted ceilings connect the main living area to an upstairs play area, while the daylit open staircase showcases wall panelling from a tree salvaged from the site. Salvaged wood was also used for the stairs and a bathroom counter. The rooftop deck offers views of Lake Washington and the Cascade mountain range.

“Inefficient buildings are the number one consumer of energy in the world, and the largest contributor to climate change,” says Cascade Built founder Sloan Ritchie. “Passive house design standards offer a way forward towards net-zero building with strategies that are relatively easy to implement – better windows and doors, more insulation, improved air sealing. Unlike asking people to stop driving their cars, passive house reduces our carbon footprint while increasing comfort and quality of life.”