PHnw Building Directory

Ashtree Passive House

Building Use: Detached single-family residence

Project Type: New passive house building

3250 gross sf single family residence with attached garage

Location:Boise, Idaho 83712
Dwelling Units:1
PH Calculation Protocol(s):PHIUS+
PH Modeling Software(s):PHPP
PH Certification(s):PHIUS
Year Of Construction:2016

Project Size

Floor Area:2,844.9 ft2iCFA264.3 m2iCFA


Heating Degree Days:5,600 °F•day/yr3,111.1 °C•day/yr
Cooling Degree Days:1,337 °F•day/yr742.8 °C•day/yr
Annual heat demand:3.94 kBtu/yr•ft2iCFA12.4 kWh/yr•m2iCFA
Heat load:3.10 Btu/hr•ft2iCFA9.8 W/m2iCFA
Annual cooling demand:1.31 kBtu/yr•ft2iCFA4.1 kWh/yr•m2iCFA
Cooling load:2.23 Btu/hr•ft2iCFA7 W/m2iCFA
Primary energy demand:35.60 kBtu/yr•ft2iCFA112.3 kWh/yr•m2iCFA
Primary energy demand after on-site generation:26.13 kBtu/yr•ft2iCFA82.4 kWh/yr•m2iCFA
Airtightness:0.01 ft3/min•ft2


Construction Type:wood
Floor Assembly:Thickened-edge slab on grade over EPS
Wall Assembly:2x6 structural wall, taped OSB air barrier, 8" z-girt assembly w/ cellulose, WRB, rainscreen (stucco or fiber-cement board)
Roof Assembly:Trusses w/ loose-fill cellulose
Windows:Zola Thermo uPVC
Entry Doors:Zola Thermo uPVC


Ventilation system:Zehnder Comfoair 350
Heating/Cooling system:(1) 12,000 Btu/hr Mitsubishi minisplit (FA12NA) lower level, (1) 9,000 Btu/hr Mitsubishi minisplit (FA09NA) upper level
Domestic hot water system:HPT Phoenix Light Duty (PH76-50) Gas-fired tank water heater
Renewables:6kw PV system (installed March 2017)


Passive House Consultant:Scott Yribar
Passive House Consultant Certification:PHIUS
Architect:Scott Yribar
Structural Engineer:Kevin Murar
Mechanical Engineer:Kara Rouselle
Contractor:Enerform LLC


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