How Building Science Shaped Passive Standards
Session Outline:
Phius and PHI share the same passive-building roots, but they no longer ask the same questions in the same way. This presentation will show how building science helped drive that divergence: away from universal targets alone and toward climate-specific, building-specific, and cost-optimized performance criteria that better reflect North American practice. The session will compare PHI and Phius through the lens of enclosure physics, thermal bridging, airtightness, ventilation, moisture control, source energy, electrification, and renewables, with particular attention to why Phius is often more feasible and more defensible for Ontario project teams trying to balance performance, affordability, and constructability.
The presentation will also show how Phius compares to and can function as a practical framework for broader sustainability and emissions goals in Ontario, including its relationship to the Toronto Green Standard, Ottawa High Performance Development Standard, LEED v5, CaGBC Zero Carbon Building, and ENERGY STAR Multifamily New Construction. It will highlight where these systems overlap, where they measure different things, and how Phius can help organize enclosure performance, operational energy, emissions, health, and verification requirements into a coherent delivery pathway. Finally, the session will ground the discussion in Ontario affordable housing delivery through a comparative look at Ottawa Community Housing work: OCH Geyser Place, designed to Phius CORE 2024 while exceeding NEBC by more than 35 percent and Ottawa’s High Performance Development Standards; OCH Mikinak Redevelopment, a 271-unit net-zero-carbon, Phius+ pre-certified community; and 811 Gladstone, a 108-unit Phius+ 2018 certified benchmark project.
Learning Objectives
- Explain how building science informed the evolution of Phius from shared passive-house principles toward climate-specific, building-specific, and cost-optimized performance targets.
- Compare PHI and Phius in terms of assumptions, metrics, and project-delivery implications for Ontario buildings, including their relationship to TGS, Ottawa HPDS, LEED v5, CaGBC Zero Carbon Building, and ENERGY STAR.
- Identify how Phius aligns with decarbonization, health, and sustainability goals through its co-requisites, source-energy pathways, electrification structure, and overlap with TGS, Ottawa HPDS, LEED v5, CaGBC Zero Carbon Building, and ENERGY STAR.
- Apply lessons from OCH case studies to the delivery of Phius-informed affordable housing projects in Ontario.
Presenter
Prudence Ferreira, CPHC, LEED AP BD+C
VP Sustainability + Resilience, Thornton Tomasetti
Prudence Ferreira is an experienced sustainability consultant with a specialization in passive house standards. She has overseen numerous PHIUS and PHI certification projects, including many large residential and commercial properties and is a certified passive house educator.
Length: 00:58:16
Last Updated: October 21, 2026
