Passive House Canada Feedback on proposed 2025 Federal Model Building Code


The latest updates to Canada’s National Model Codes introduce significant changes aimed at improving operational emissions from buildings. Passive House Canada welcomes tiered GHG emissions requirements, mandatory airtightness at higher tiers for smaller buildings, Energy Use Intensity (EUI) compliance path, and the inclusion of health costs when weighing the inclusion of code changes. These changes represent a progressive shift towards performance-based standards, which, if widely adopted, could substantially decrease the operational emissions associated with new and retrofitted buildings.  

However, the effectiveness of these updates is limited by an uneven requirement for airtightness testing, multiple compliance pathways that keeps the door open to reduced performance, a lack of ambitious sunsetting of high emitting energy systems, a lack of improvement in energy efficiency in the lower tier and the voluntary nature of advanced tiers. Further, code adoption is challenged by provinces that have shown reluctance in aligning with national efficiency standards and harmonization.  

The code is an improvement on the previous iteration but is not a net-zero building code. With embodied carbon slated for the next 2030 iteration, with perhaps resiliency included in that update, and circularity consideration far outside the mainstream conversation, there is still much work to do in order to solve many of the country’s environmental challenges. 

Feedback on specific changes 

Passive House Canada would like to say thank you to Efficiency Canada and The Atmospheric Fund for their collaborative assistance in identifying strengths and weaknesses in the latest proposed change to the model building code. 

Introduction of tiered GHG emissions targets  

  • Code Change 2003  – Support with modifications

The national model codes introduced tiered GHG requirements specifically targeting operational GHG emissions. These tiers set benchmarks for emissions reductions that buildings must achieve, depending on the tier chosen. This structured approach is crucial as it allows incremental improvements and flexibility for different building types and local conditions. 

This change integrates operational GHG considerations into the building design. It is a foundational shift that embeds carbon considerations into the compliance framework of building codes, targeting the operational phase, which is a significant source of emissions over a building’s lifecycle. 

Unfortunately, the GHG emission targets can be achieved through a reference model and a prescriptive path. The prescriptive path includes a points system where high GHG sources, such as gas heaters, are awarded points equivalent to more efficient technologies like heat pumps. This equivalency in points can undermine the effectiveness of GHG reduction goals because it fails to differentiate between the overall environmental impacts of these energy sources. The inclusion of GHG targets is negated by a weaker prescriptive path.  

Geographic exclusions for remote and rural areas recommended 

Passive House Canada recommends the introduction of geographic exclusions in the building code, especially for remote and rural areas where access to advanced energy systems like heat pumps may be limited. Such exclusions would recognize the unique challenges faced by these areas and allow for more appropriate and achievable compliance standards that reflect their specific circumstances. 

Absolute GHG target for compliance recommended 

To simplify compliance and enhance the effectiveness of GHG reduction efforts, Passive House Canada recommend establishing an absolute GHG target for compliance. This approach would replace the current model that requires builders to compare their projects against a hypothetical reference building, thereby streamlining the compliance process and focusing directly on measurable and meaningful reductions in GHG emissions. This would ensure a clearer, more direct path towards achieving Canada’s environmental and climate objectives. Having an absolute metric for GHG emissions also allows project teams that choose the performance pathway to not have to do additional unnecessary modeling of reference building to provide evidence of compliance for the GHG requirements.  

Performance pathway introduced but uneven: Energy Use Intensity (EUI) compliance path 

  • Code Change 1868 – Support with modifications

The inclusion of an EUI-based compliance path marks a significant shift towards performance-based standards. By focusing on the actual energy use per square metre, the codes promote more efficient building operations and directly influence operational energy consumption, aligning with GHG reduction goals. 

Despite its progressive intent, the latest updates to the building code still incorporate significant prescriptive elements alongside the performance-based standards. This means that builders and designers, to ensure effective modeling and compliance, can navigate either a performance-based (EUI) pathway, reference building pathway of a reduction of energy use by percentage against a hypothetical model, or prescriptive pathway, a point-based system. These multiple pathways complicate the compliance process and could lead to inefficiencies and redundancies in the design process by requiring multiple models for different aspects of the same project —specifically, a performance-based model for the EUI and a reference-based approach for GHG emissions compliance. These multiple compliance pathways also keep the door open to reduced performance outcomes. 

Passive House Canada recommends other pathways be sunset in the future in favour of an absolute performance target, especially in regard to Part 3 Buildings. 

Continue to keep GHG targets and EUI linked 

As it is now, continue to maintain the linkage between GHG emissions targets and EUI because it is vital for enforcing a comprehensive approach to building efficiency. The current electrical grid capacity could be strained by increases in demand from new technologies and higher consumption levels, making the integration of efficiency measures and low-emission energy sources more crucial than ever. By keeping GHG and EUI targets interlinked, we can ensure that buildings are not only energy-efficient but are also utilizing the cleanest energy possible, thus supporting broader environmental goals without overwhelming infrastructure capabilities. 

Uneven introduction of mandatory air tightness 

  • Code Change 1868 – Support with modifications

The recent updates to the national model codes have introduced mandatory air tightness testing at higher performance tiers for Part 9 buildings, generally smaller residential structures. This change is a significant step towards enhancing energy efficiency by ensuring these buildings meet stricter air tightness standards. However, for Part 3 buildings, which include larger commercial and multi-unit residential buildings, the new codes do not mandate air tightness testing on any tiers. This oversight means that larger buildings, which often have a more substantial impact on overall energy consumption and operational emissions, have no required verifiable pathway to meet performance standards. This regulatory gap points to a need for a more consistent application of air tightness requirements across all building types, to better align with the goals of reducing energy use and operational emissions universally across the construction sector.  

Implementing air tightness testing in the upper tiers for larger buildings could set a market signal that underscores the demand for enhanced energy performance, which in turn could stimulate the market for such testing services. Currently, there may be a lack of capacity to conduct extensive air tightness testing for large buildings, but without a clear signal from the regulatory environment, there is little incentive to develop this capacity. By mandating air tightness testing across all building types, we can ensure a consistent approach to energy efficiency and emissions reduction, helping to meet broader environmental targets and prompting industry-wide adjustments that support a sustainable construction sector. 

Enhance building safety in air tightness measures for retrofits recommended 

Code Change 1827 and 1828 – Support with modifications

Passive House Canada recommends when implementing air tightness measures and envelope improvements to improve building efficiency, especially during retrofits, it is crucial to integrate balanced mechanical ventilation systems, such as Heat Recovery Ventilators (HRVs) or Energy Recovery Ventilators (ERVs), particularly in buildings where appliances like atmospherically vented natural gas furnaces or water heaters are used. These appliances are typically vented through a chimney or stack, allowing exhaust gases to exit the building. However, increased building envelope tightness can inadvertently lead to dangerous backdraft scenarios, where exhaust gases are drawn back into the building, potentially causing carbon monoxide poisoning. 

To mitigate these risks, any strategy to tighten the building envelope should include upgrades to the ventilation system to ensure mechanical balance and proper exhaust. It is also advisable to consider replacing older, low-efficiency appliances with higher-efficiency direct vent models or electric heatpumps to reduce overall energy use and enhance indoor air quality. However, recognizing that not all homeowners can afford such upgrades, it is essential to provide clear guidance and support through retrofit coaching. This will help prevent unsafe DIY retrofitting that fails to address the complex interactions between building tightness, ventilation, and appliance efficiency. 

Inclusion of health care costs a welcomed addition 

  • Code Change 1713Support with comments

The inclusion of healthcare costs related to radon exposure in the building codes is a critical and welcome development. By demonstrating the health benefits and reduced costs on the health care system, of proactive measures like radon stacks, which lead to significant reductions in lung cancer treatment costs, the national building code should consider expanding this lens to other areas such as air tightness. This approach can encourage the adoption of comprehensive health-oriented building standards that address a variety of environmental health risks, potentially leading to broader reforms that prioritize resident well-being and long-term public health cost savings.  

For example, during the Ontario forest fires between June 4-8, 2022, the estimated health cost associated with changes in ambient air quality was a staggering $1.28 billion. In BC after an unprecedented “heat dome” killed an estimated 600 people, the Chief Coroner highlighted a critical issue: 98% of heat-related deaths occurred indoors, predominantly in homes lacking adequate cooling systems. The coroner recommended the province adopt regulatory changes and building code changes that mandated passive and active cooling requirements. By integrating healthcare costs into building codes, policymakers can create a more comprehensive evaluation of the true cost of building standards.  For instance, heat pumps provide a low cost electric heating and cooling that with a clean electricity grid can help mitigate and adapt to climate change and improve air quality, reducing health care costs and other related costs associated with the physical risks of climate change. 

Lack of phasing out of most polluting energy systems 

  • Code Change 2000 – Do not support

The new building code updates are inadequate in phasing out high-pollution sources of fossil fuels, failing to align with the urgent need for a transition to cleaner energy sources. The code’s fuel-agnostic approach does not actively discourage the use of fossil fuels. Furthermore, the prescriptive pathway’s allowance for fossil fuel-based systems under certain conditions undermines efforts towards full electrification and renewable energy use, perpetuating the use of fossil fuels by providing a compliance route that does not prioritize significant carbon reduction. These shortcomings highlight the need for a more proactive approach in future code revisions to effectively phase out fossil fuels in building operations. 

Lack of ambition in lower tiers 

  • Code Change 1989 and 2004 – Support with modifications

A lack of ambition in lower tiers and the absence of a clear plan to phase them out significantly hinder the potential of the building codes to drive comprehensive energy efficiency and emissions reductions across the construction sector. The lower tiers of the tiered GHG emissions performance still align with older, less stringent standards, which do not adequately challenge builders to adopt more advanced energy-saving and low-emission technologies. This retention of lower standards perpetuates a baseline that is increasingly misaligned with current environmental urgencies and technological advancements. Without a scheduled phasing out of these lower tiers, the building codes risk becoming outdated, failing to catalyze the necessary shift towards more sustainable and energy-efficient building practices that are vital for meeting national and global climate targets.


Submit comments on building code changes

You can comment on each code change Canadian Board for Harmonized Construction Codes website until April 29th