The focus of the meeting was a presentation from NRC, which provided a comprehensive overview of the modelling approach used to develop Tier 5 prescriptive energy efficiency packages.

The NRC researcher explained that modelling was based on performance path simulations using 240 archetypes, to ensure that at least 80% of them met Tier 5 requirements. The process involved cost optimization using generic algorithms (the lowest cost archetypes were targeted). The resulting packages were compared against both the performance path and the points-based path. The findings showed that the Tier 5 packages slightly exceeded the minimum point threshold and performance metrics, indicating that they were more stringent but broadly applicable.

CHBA raised concerns about overshooting performance targets and the associated cost implications. Additionally, several members supported relaxing the 80% compliance threshold for smaller homes, noting that they are inherently energy efficient. A key debate emerged around whether to continue using the performance path or shift to the points-based path for developing prescriptive packages. Over time, a consensus emerged in favour of the points-based approach, citing its consistency, simplicity, and alignment with existing compliance options.

The meeting concluded with agreement to recommend the points-based methodology for future modelling, pending approval from the National Mode Code Committee on Climate Change Mitigation (NMCC-Miti). It was also decided to revisit the Tier 5 packages for alignment and to defer further discussion on airtightness and small homes criteria until the next meeting.

For any questions, please contact alex.bols@chba.ca

The meeting agenda materials can be found here: