North River Architecture & Planning, PC has been awarded PHIUS+ pre-certification for this 1,730 sf single-family residence, currently still under construction. The house is being built using standard building techniques and materials, although the foundation is non-standard for this area: a frost-protected shallow foundation, which we found to be a very good solution for Passive House by using insulated forms along with 8” of EPS under the concrete slab of the floor. Airtightness above grade is achieved with taped ZIP sheathing and SIGA tape products at doors and windows. Windows are triple glazed Zola aluminum clad wood tilt/turns; doors also triple glazed and by Zola. Insulation is very cost-effective, with dense packed cellulose and 4” of exterior polyisocyanurate forming the R-43 exterior walls, and loose blown cellulose in R-84 ceiling.
The house has a 9kW photovoltaic array on roof, which is expected to make this a Net Zero building, producing more energy annually than the building requires. The contractor team had no prior experience with Passive House and have done excellent work throughout, with on-the-job training by the North River team to ensure envelope airtightness and PHIUS quality standards.