PHnw Building Directory

Park Passive

Building Use: Detached single-family residence

Project Type: New passive house building

Park Passive is the 2014 recipient of the national AIA Housing Award and the 2016 recipient of the PHIUS Design Award. Located in Seattle’s Madison Park neighborhood, the building is home to an active family of four with an interest in sustainability and modern design. The constraints on the 2,710 SF home and its 2,000 SF urban lot were abundant, including a small, shallow floor plate; a zoning envelope that required working within the form of the existing house; limited solar access; and 17” thick walls. The design team addressed these challenges by emphasizing vertical space and playing with wall thickness on the front façade. This led to interesting surprises, such as the double-height vaulted kitchen space that visually connects the main living area to the upstairs kids play area; a day-lihgt open stair punctuated with views to the street and a carved out nook for a window bench; and several large skylights. The design also widened the floor plate and addressed the lack of a back yard by creating a strong tie to the front yard using a large lift-slide door and expansive glazing.

Location:Seattle, Washington 98112
Dwelling Units:1
PH Calculation Protocol(s):PHI
PH Modeling Software(s):PHPP
PH Certification(s):PHI
Year Of Construction:2014

Project Size

Floor Area:1,959.0 ft2TFA182 m2TFA


Heating Degree Days:4,742 °F•day/yr2,634.4 °C•day/yr
Annual heat demand:4.76 kBtu/yr•ft2TFA15 kWh/yr•m2TFA
Heat load:4.12 Btu/hr•ft2TFA13 W/m2TFA
Primary energy demand:36.77 kBtu/yr•ft2TFA116 kWh/yr•m2TFA
Airtightness:0.6 ACH50


Construction Type:wood
Floor Assembly:The basement floor is slab on grade, with 4 inches of concrete, 16 inches of gravel, and 8 inches of EPS insulation (R4.6 per inch).
U-value = 0.147 W/(m2K)
Wall Assembly:The exterior walls are a layered construction starting with a gypsum layer, 5.5 inches of denspack fiberglass (R4.2 per inch), plywood sheathing with taped seams to create the air barrier, 9.5 inches of dens pack fiberglass (R4.2 per inch), and fiberboard
U-value = 0.0203 W/(m2K)
Roof Assembly:The primary roof assembly begins with a gypsum layer, then 3.5 inches of denspack fiberglass (R4.2 per inch), then a layer of taped OSB for air barrier, then 15.75 inches of dens pack fiberglass (R4.2 per inch), a sheathing layer, then 4 inches of Roxul mineral wool (R4.17 per inch).
U-value = 0.09 W/(m2K)
Intus, Eforte, Prestige, and Lift+Slide product
U w-value = 0.89 W/(m2K)
Intus Triple-Glazed 4Low E x16x4x16x4 Low E
Fakro Skylight Glazing
U g-value = 0.6 W/(m2K)
g -value = 62 %
Entry Doors:PRESTIGE doors by Intus
glazed doors
U d-value = 1.07 W/(m2K)


Ventilation system:Zehnder, Comfoair 350 HRV
Ventilation for supply and extract air with heat recovery.
effective specific heat recovery efficiency: 91%
Heating/Cooling system:direct electrical, ECO-heater NA400S, wall-mounted ceramic convection heater.
Mitsubishi SEZ KD18NA4 ducted mini split for cooling upstairs.
Domestic hot water system:Sanden CO2 heat pump water heater: GUS-A45HPA
Other green building systems:Xeriscape. Use of salvaged trees onsite for interior finishes. No VOC paints.


Passive House Consultant:Rob Harrison
Passive House Consultant Certification:PHI
Architect:NK Architects
Contractor:Cascade Built


Additional Information:Passive House consulting: Rob Harrison
Passive House construction advisor: Dan Whitmore
Project Website:

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