Seattle’s first Passive House-certified home

written by mr.paul on February 26, 2014 in Passive House and Residential with no comments

passive-house-certified
Madison Park, Seattle, Washington (NK Architects)

Quick note about Passive-House Certified: Passive, in this case, refers to heating and cooling without the use of mechanical systems. A Passive-House certified home is one that, by passive means and energy efficient building strategies, consumes between 75 and 95% less energy for space heating and cooling than current new buildings that meet today’s US energy efficiency codes.

Seattle’s first Passive House-certified home is big news for: Seattle, $avings for the home owner, better building, air quality, relief from fossil fuel dependency, and the health of the environment we live in that in turn effects the health of people that live within it.

Article scraps… Fenestrating the north, the public face of the house posed a slightly different problem. “Because the house has no backyard, our strategy was to open the house to the front yard and make the living space feel much larger on the first floor,” McCunney says, and now a combination kitchen-living room is separated from a screened front patio by an expansive sliding door. “Yet Passive House in a climate like Seattle really wants to limit north-facing windows, and opening the front space to the yard in this way required a steel header that’s a thermal bridge. You have to have a tradeoff somewhere else.” NK decided that that “somewhere else” would be the roof, whose 89.3 R-value is the result of an insulated joist topped in rigid polyisocyanurate insulation.

Walls are approximately 17 inches thick. An insulation wall formed with TJI joists hangs outside the 2-by-6 structural wall, and the sheathing panel installed beyond that serves as the mount for the house’s corrugated metal siding. A heat recovery ventilator provides continual fresh air year round.

NK confronted forks in the road beyond the steel header. Since it had to organize the building vertically to achieve the desired square footage, for example, it transformed the stair into an asset, expressing it in fiber cement board on the exterior and placing windows at various heights to make its landings enjoyable for both the homeowners and their children. A mature ash tree had to be taken down to build the bigger house, but now its wood clads the stairwell interior and comprises its treads. These and other decisions affect neither the Ritchies’ lifestyle nor their eco-performance as the house consumes as much as 80 percent less energy than comparable code-built new construction.

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“You can design a Passive House as a box with punched openings that performs perfectly for your energy modeling,” McCunney says of the tradeoffs theme, “but for architecture to be truly sustainable, it has to be livable and pleasant, too.” Armed with this more nuanced understanding of high-performing residential building, NK, like Cascade Built, is applying its Passive House wisdom to additional, as well as larger-scale, residential efforts…

Full article: A Recipe for Madison Park – Best Green Houses – Greensource Magazine.