Net zero Emissions Code – Efficiency Canada’s
public review comments

We strongly support the CBHCC for its efforts to include objective(s) for greenhouse gas (GHG) emissions to enable provincial and territorial regulation into the 2025 codes.

March 23, 2023

Policy Work | Submissions

The Canadian Board for Harmonized Construction Codes (CBHCC) is seeking  input from stakeholders on the draft policy recommendations for developing/implementing greenhouse gas provisions in the National Model Codes. Information on the consultation is available via the: Consultation overview. This initial consultation wave was announced via Construction Innovation. Consultation wave 1 begins on February 6, 2023 and ends on March 30, 2023. Wave 2 will run from April 27th to May 7th.

We strongly support the CBHCC for its efforts to include objective(s) for greenhouse gas (GHG) emissions to enable provincial and territorial regulation into the 2025 codes.

New buildings constructed under the net zero emissions building code will last for half a century or more. By directly addressing emissions in new buildings through the national model codes,
Canada can lock in immediate and long-term emission reductions, and accelerate further reductions in other areas such as the electrification of existing buildings and transportation. Along the way, the building sector can catalyze further reductions in upstream emissions, in particular those emissions arising from electricity generation or those within building materials or construction processes.

The end goal and defining net zero emissions

The federal government has committed to the development and implementation of a net-zero emissions building code as a means to help Canada reach its greenhouse gas emissions reductions target that aims to cut emissions 40-45% below 2005 levels by 2030 and to reach net
zero emissions by 2050. Nonetheless, there remains ambiguity and uncertainty about what the term ‘net-zero emissions’ means for newly constructed buildings.

Typically, net-zero emissions refer to the balancing or canceling out of any emissions associated with the building’s operations and materials, including equipment used in its construction. The ‘net’ component of net zero is typically achieved through offsets that provide an emission reduction elsewhere, typically outside the scope of the building code. Such offsets include, for example, renewable energy sources or waste heat or heat recovery to offset remaining operational or embodied emissions.

Given the potential for buildings to store carbon and free up existing clean electricity resources, it will be important for a “net-zero” strategy to not “get caught in the net” as warned by Canada’s Net-Zero Advisory Body. This means the net zero emissions code must seek to achieve zero emissions in buildings without the use of offsets. Doing so will help code users recognize the value of energy savings from fossil fuels as well as increased use of clean electricity resources, while considering the role of carbon storage within buildings.1

Recommendation: The end goal of the net zero emissions code should be to achieve zero operational emissions in newly constructed buildings, and increased use of carbon sequestering building materials. In doing so, the building sector can avoid acting as a burden for the rest of the economy’s net-zero goal by requiring offsets. Instead, the goal should be to be a net contributor to GHG economy-wide GHG reductions through the use of carbon sequestering materials. And these carbon sequestering materials should be viewed as the means to offset higher emissions building materials used in the construction of new buildings.

The net-zero emissions code is a chance to transform our buildings and the materials used in their construction, from a source of emissions to instead store carbon and reduce emissions throughout their life cycles. Tracking and monitoring material emissions in new construction, for example through a building logbook, can lead to new opportunities to use buildings and construction materials as an emissions sink, and find high-value applications for material reuse. Innovation in this area could allow builders to claim end-of-life savings off materials in pursuit of zero-carbon building standards.

Recommendation: Forgo net-zero offsets as they are inappropriate for new buildings that can be designed to be near zero emissions from the outset. To contribute to Canada’s 2030 and 2050 climate commitments, the long-term approach to achieving net zero emissions must reduce operational and embodied emissions through design and construction as well as mechanical equipment selection, and ‘offset’ higher emissions materials with carbon storing materials.

If a further balancing of emissions is required to achieve net zero emissions, the use of renewable energy and electric vehicle readiness should be considered in future code cycles as a means to offset remaining emissions.

The boundary of operational emissions and embodied emissions

Tackling operational emissions requires a direct approach. As the BC Energy Step Code (ESC) has shown, stringent energy performance targets such as those provided by the 2020 model codes are not a driver for mechanical system selection. While compliance with the ESC’s requirements can be met with any type of heating system, there is a significant variation in GHGI at each step. For example, the GHGI for a large single family dwelling at the highest tier using an electric heat pump is 93 per cent lower than the same building using an all-gas heating system. This trend extends to part 3 buildings as well, with the GHGI at the highest step being 87 per cent lower on average for heat pump systems versus all-gas systems across all

Other provinces do not have the very low GHG emissions intensity of BC’s electricity system. Nonetheless, the IEA has found that installing heat pumps can significantly reduce emissions, even with Canada’s electricity generation mix because of their high energy efficiency performance. The net-zero emissions code should also be developed in anticipation of Canada’s Clean Electricity Standard. This means new buildings constructed with low emissions heating and hot water equipment today can capture immediate benefits and be net zero emissions in the coming years as efforts to decarbonize the electricity system are realized.

Like the City of Vancouver’s Zero Emissions Building Plan and the Toronto Green Standard, the net zero emissions code should apply GHGI limits (expressed as kg CO2/m2/year), as well as incorporate a Thermal Energy Demand Intensity (TEDI) metric to limit the thermal energy losses through the building envelope and Energy Use Intensity (EUI) metric to lower the total amount of direct and indirect energy used for heating, ventilation, and hot water, as well as appliances and equipment. Both a performance and prescriptive compliance path should be available to code users in the 2025 net zero emissions code.

Recommendations for operational emissions

Recommendation: Eliminate the building codes’ fuel-agnostic approach that treats all fuels used for building operations equally. If the goal of the net-zero emissions code is indeed to decarbonize the buildings sector, there will be a substantial role for the use of low-emissions electricity heat pumps that produce fewer emissions than fossil fuels2 even when accounting for potential refrigerant leaks.3 These low-carbon heating systems should be incentivized in code requirements, given that the goal is to achieve zero/net zero emissions.

We support the CBHCC’s recommendation to address both scope 1 and scope 2 emissions in the 2025 model codes, and that a standardized and fixed emission factor for grid-level scope 2 emissions be set for each province/territory based on Environment Canada and Climate Change data.

Recommendation: Consider energy efficiency as a starting point for cutting operational and embodied emissions. Energy efficiency is a globally recognized pathway to building sector decarbonization. Reducing both operational and embodied emissions in the building sector begins with cutting energy wasted throughout the building’s life cycle.

At the design stage, energy efficient buildings typically reject needlessly complex roof or floor plans in favour of simpler building ‘form factors’ that reduce the building’s envelope area. This means fewer materials are required—and wasted—throughout the extraction, transportation, and application of materials, leading to reductions in embodied carbon. These material efficiency strategies can cut cement and steel demand in the buildings sector by more than a third relative to today’s conventional standards without associated cost premiums4

In operation, these same energy efficiency measures reduce a building’s energy needs so that renewable energy or zero-carbon energy sources can meet all space conditioning requirements. In particular, mandating high levels of airtightness in buildings can serve to reduce heating and cooling demands that not only enable the use of ‘right-sized’ heating and cooling equipment, but also reduced levels of insulation, thereby cutting operational and embodied emissions significantly. As a result, energy resources are freed for higher value uses, like meeting growing demands for widespread electrification (of both buildings and vehicles) without the need for additional electricity system infrastructure.

These fundamental steps should be considered a critical component of any net-zero emissions standards. There is a risk that some actors might seek to avoid energy efficient design changes and construction practices assuming that simply switching existing materials for low-carbon building materials will lead to zero or net-zero emissions. That will create missed opportunities to achieve deeper emission reductions while capturing the many co-benefits of energy efficiency.

Recommendation: Cut operational emissions by establishing GHGI and thermal energy limits: As a stand-alone measure or incorporated into the 2020 model code’s tiers, GHGI limits (expressed as kgCO2/m2/year) can be complemented by a Thermal Energy Demand Intensity (TEDI) metric to limit the thermal energy losses through the building envelope and Energy Use
Intensity (EUI) metric to lower the total amount of direct and indirect energy used for building operations.

This approach focuses on highly efficient building envelopes (and mechanical HVAC systems) as simple and long-lasting measures to reduce operational emissions that have the added benefit of enhancing the climate resiliency of buildings by offering occupants stable indoor temperatures in the event of extreme weather events or power outages. Incorporating these systems into the building design and construction phase avoids the need to undergo costly and disruptive time retrofits in the future.


Recommendation: Provide prescriptive measures for reductions in operational emissions: Prescriptive measures establish minimum acceptable standards for specific building elements. As such, this approach can be paired with tiered energy code provisions to tackle heating/cooling and hot water equipment to reduce operational emissions as follows:


● Tier 1: Measure a building’s emissions without reductions to build knowledge and capacity.
● Tier 2: Require space heating to be low carbon.
● Tier 3: Require both heating and hot water to be low carbon.
● Tier 4/5: Fully decarbonize the building (fireplaces and cooking equipment included).


Recommendation: Develop a tiered framework for operational and embodied emissions to be aligned with, and act in concert with, the energy tiers of NECB 2020 and NBC 2020. As the example above demonstrates, the tiers should progressively cut emissions from building operations, including those beyond heating and hot water systems. A tiered framework will offer authorities having jurisdiction (AHJ) greater flexibility in code implementation while allowing municipalities to advance at a pace that meets the capacity of their local market.

Recommendations for embodied emissions

There is only one opportunity to reduce embodied emissions in buildings—at the beginning of that building’s lifecycle. Where operational emissions could be reduced overtime through future energy efficiency measures, embodied emissions are locked in as soon as a building is built. This is why incorporating embodied emissions is so important for the design of a net-zero emissions building code.

Research and data collection on Lifecycle Analysis processes and Environmental Product Declaration is continuing to evolve and improve. However, that is not a reason to delay action. In the near term, there are many opportunities to significantly reduce embodied emissions via
material substitutions or replacement, with limited to no impact on cost and schedule. In large buildings, a 30 per cent reduction in embodied carbon is possible by substituting common common concrete, steel, and insulation materials with low-carbon materia alternatives, without impacting project cost or schedule.5 In residential buildings, material substitutions have demonstrated that it is now possible to rapidly cut embodied emissions by half using the best materials available today, for a conventional and cost competitive residential building6.

Further supports for measuring embodied carbon are under development. The National Research Council’s low-carbon assets through life cycle assessment (LCA2) initiative is underway. This project expects to develop a product level approach that will offer a way to identify low-carbon materials and address shortcomings in existing approaches to LCA/EPD and establish guidelines that account for variation in the construction, use, and end-of-life stages of a product.

Recommendation: Implement a ‘measure only’ approach for embodied emissions in 2025 to further develop the market for low-emissions structural materials and include prescriptive measures: To address the embodied emissions of structural materials, a measure only requirement could be used to both signal that embodied emission reductions are a code objective and incoming requirement and raise awareness that these requirements will be expected in future code editions.

In addition to preparing building sector stakeholders, and helping to avoid a rushed implementation of embodied emissions measures in coming code cycles, an added benefit of this approach is that AHJs, and by extension the building codes development system, will capture real-world data on embodied emissions in new construction that can inform future code requirements.

For large buildings (Part 3) a measurement only approach could require an Life Cycle Assessment calculation without a threshold limit value. Smaller, residential buildings (Part 9) constructed under the performance path could include a whole building life cycle analysis or material emissions assessment using Natural Resources Canada’s Material Carbon Emissions (MCE) estimator tool or a simplified reporting tool for common structural materials.

Prescriptive measures to reduce embodied emissions: Developing a prescriptive approach to limiting GHG emissions in structural construction materials for the 2025 code cycle could quickly achieve emission reductions from high-emitting materials such as concrete, steel, and insulation.

While the best approach to reducing embodied emissions is to employ a project-specific, whole-building, cradle-to-grave LCA study—a prescriptive approach can offer immediate reductions in emissions from common building materials such as concrete, steel, and insulation. To provide assurances of real emission reductions, this approach should be implemented alongside a robust LCA or use established product EPDs.

Recommendation: Performance requirements for embodied carbon should take into account material level emissions, as well as a whole-building lifecycle assessment. This assessment should be based on the Canada National Research Council National Guidelines for Whole Building Life Cycle Assessment, June 2022. Given the current limitations of EPDs, a simplified LCA assessment focused on structural and envelope components that aligns with the approach taken by LEED and the CAGBC is recommended.7

Laying the foundation for the transition to zero-carbon buildings

Canada’s national model codes represent one of the most effective policy instruments to accelerate our transition to zero-carbon buildings. Few instruments in the federal government’s current climate toolbox are as effective in transforming the market for buildings that are net-zero energy or net-zero emissions as the building codes can be.

A net zero emissions building code is a highly effective tool that can help establish clear market signals to industry, manufacturers, and consumers. By setting and defining long-term and durable net-zero emissions standards, the net zero emissions code will deliver the certainty market actors need to direct investments in low-carbon technologies, processes, and infrastructure to meet the demands of the buildings sector. In turn, the net zero emissions code can lay the foundation for an ambitious standard of new construction in Canada that ensures each new building constructed will contribute to Canada’s net-zero goals and long term resilience.




2 There are valid concerns related to the use of refrigerants in heat pumps which can have high global warming potential (GWP). These concerns can be offset with federal or provincial regulations on the allowable refrigerant types based in part on GWP.

3 International Energy Agency. The Future of Heat Pumps. November, 2022.

4 International Energy Agency, Net Zero by 2050 – A Roadmap for the Global Energy Sector. October, 2021.

5 Regulating Embodied Emissions of Buildings. Insights for Ontario’s Municipal Governments. Policy Primer, August, 2022.

6 Magwood, C., Bowden, E., Trottier, M. Emissions of Materials Benchmark Assessment for Residential Construction Report (2022). Passive Buildings Canada and Builders for Climate Action.

7 See Table 4, Regulating Embodied Emissions of Buildings. Insights for Ontario’s Municipal Governments. Policy Primer, August, 2022.


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