A highly transferable example of how to intensify existing communities, adding to their capacity and improving their energy performance. The ambition to take this rather unremarkable existing house to an exceptionally high level of energy performance is to be applauded, as is the suite of innovative but highly transferable strategies that were used. It is also noteworthy that the project team decided to build upward rather than outward, and to restore previously paved areas of the site to natural landscape.This project has transformed a post-World War II bungalow into a highly-efficient two-storey home: a retrofit that exceeds Passive House air-tightness standards. The project was developed using an integrated design process to optimize performance in the areas of energy efficiency, indoor air quality and water consumption.
Building geometry and glazing were optimized for passive solar gain during the heating season and solar exclusion during the cooling season. Super-insulation, an airtight building envelope, and mechanical ventilation with energy recovery serve to minimize space-conditioning requirements.
Heating and cooling are supplied by a heat pump which uses a shallow geothermal loop to collect or reject heat. Distribution to the home is via radiant ceilings and an in-slab radiant system in the basement. These systems maintained comfortable conditions [without the need for supplementary heat] throughout the first winter of occupancy, when temperatures dipped as low as -2 C0.
The home backs onto the Don Valley, meaning that all changes to the property require permission from municipal authorities for ravine management. The existing deck was in need of major repair and in order to limit the impact on the ravine, the design decision was made to build a new smaller deck. To limit work within the ravine, helical piles were used instead of concrete to support the new structure.
To reduce runoff from the property, and the potential for erosion in the adjacent ravine, the home is plumbed to collect rainwater in an underground cistern. By way of a separate supply manifold, this water will be recycled for non-potable uses such as irrigation, toilet flushing and laundry. The conservation of embodied energy was a priority for the project. The existing masonry and original floor joists of the home were retained. All appliances, doors, boiler and radiators were donated.
New materials included: FSC-certified framing lumber; lead-free brass plumbing fittings; triple-pane, argon-filled, fibreglass windows; 40% SCM content concrete; high recycled content drywall; low-VOC paints; recycled denim batt sound insulation and regionally-sourced maple flooring. This low- energy home offers the prospect of healthy and affordable living over the long term, independent of any fluctuations in energy prices. The owners want to share the lessons learned with their community. Prior to completion, the home was part of OSEA’s Green Energy Doors Open event, and the owners want to continue using their home as a teaching tool, particularly for architecture and engineering students from local university programs.
General Contractor Greening Homes Ltd.
Architect Open Architects
Mechanical Engineer Sustainable EDGE
Article and images by SAB Mag, Issue Number 48, Summer 2015