On May 5-7th 2025, Cahdco had the opportunity to attend the Passive Housing Canada Conference, which was held in Ottawa. The conference focused on improving the design process of Passive House through replicable design and strong collaboration between the project team.
There was a strong contingent of affordable housing providers and developers in attendance and presenting their own projects at the conference. Affordable Housing providers are at the forefront of Passive House design and construction of Multi-Unit Residential Buildings (MURBs) in Canada, as affordability and sustainability are inherently linked and prioritized through many funding programs.
What is Passive House?
It can be described as a building standard and set of design principles which aim for the highest performance in sustainable building practices and energy efficiency. A design standard is similar in many ways to Net Zero, but goes beyond in its goals to maximize energy efficiency through building design, optimizing energy gains and minimizing losses to the best of its ability. With the increasing energy efficiency minimum requirements being incorporated into Building Codes, more project teams are incorporating Passive House or other standards into their projects as a baseline.
The most common themes of Passive House design include:
- Air tightness: Buildings are the highest efficiency in mitigating air leakage, in order to reduce heat loss in the winter and cooling loss in the summer.
- Thermal Transfer/Bridging: The reduction of heat/cold transfer from the indoor temperature to the outdoors by utilizing materials (the bridges) with high R values, such as continuous insulation, and high-efficiency windows, to mitigate.
- Windows and Shades: Using smaller windows and shading techniques that optimize the winter sun while reducing the sun’s heat in the summer.
- Mechanical Ventilation: With such high air tightness, ventilation is needed to bring fresh air in and stale air out, such as using energy recovery ventilation systems (ERV) to retain indoor energy for heating or cooling.
- Renewable Energy: Solar panels are typically an essential part of any Passive House development, with Geothermal also being an option on larger projects.
- Simple Geometry: By utilizing simple geometry, Passive House buildings are able to reduce the number of thermal bridges and air leakage through complex component connections.
What did we learn?
Below we synthesized what we learnt from different sessions at the conference into key themes that affect the use of Passive House Standards in affordable housing.
Education and Collaboration
With Passive House still being new to the mid-high-rise development space, there is a significant need for education of all members of the project team. Unlike regular development projects, Passive House and other high energy efficiency projects need everyone to understand how every aspect of the project is interrelated. From your energy modeller to architect, to construction manager, to every specialist on the construction team, understanding the principles of passive house design is essential to a successful project. Many panellists touted the use of the Integrated Design Process (IDP) to ensure project success. IDP is a type of collaborative approach that aims to achieve early alignment and input from all parties. Maintaining that continuity and feedback through construction is crucial for meeting the Passive House standards. Another topic reiterated by several speakers was the importance of replicable design and lessons learned. As building to Passive House standard in mid-rise developments is still quite new to North America, many case studies expressed how each project they did, they learned from previous mistakes, and refined the process to provide a more streamlined process each time.
Offsite Construction Possibilities
Many of the case studies presented discussed the usage of panelized, prefabricated or modular design integrated with passive house design. This refers to the practice of assembling parts or entire structures at a facility or factory and then transporting them to the final construction location.
In one case study presented, which utilized modular design, each module had its air barriers assembled in the factory, with individual air tightness testing and inspections taking place in the modular factory, before being brought to the site. The modules then had to be assembled like building blocks on site, connected using sheer plates, and tying in each air barrier system for a continuous air barrier. This case study also identified several challenges with using modular construction, including the difficulty of delivering large modules to a downtown site. Modules can also be damaged when being brought to the site. Especially if scheduling and weather present challenges for the project. Modules must be appropriately stored and protected on site to mitigate the risk of damage.
Panelization was identified as an alternative method which are much easier to bring to the site, with fewer issues.
Decreased Carbon Impact
Multiple discussions outlined the ways that buildings have a carbon impact throughout their life cycle. This impact will be tracked and prioritized in future building metrics, both during permitting and in future iterations of the Building Code. The impact is controlled and measured in the following ways:
- Material Selection: The production of building materials has a carbon impact, which may guide the design team to provide alternative selections to mitigate the impact of the material selections.
- Construction Carbon: During the construction phase of the project, carbon is used in the assembly of the building and the shipping of materials to the site. This also comes into play at the end of the building’s lifecycle, when demolition is required, placing additional carbon impact on the project.
- Operational Carbon: The energy usage of the building during its operation, including the type of energy used, is calculated over its lifespan. This portion can be reduced by making mindful selections of systems, introducing renewable energy into the project and keeping operational energy usage to a minimum through appropriate design measures.
