This paper identifies and examines policy elements developed by the Canadian Board on Harmonized Construction Codes (CBHCC) related to the development and implementation of code provisions related to a greenhouse gas (GHG) emissions objective for new houses and buildings in Canada (“GHG emissions codes”). The subject issues were initially identified by the Provinces and Territories (P/Ts) as elements needing policy consideration in order to support the development of technical provisions.

The following policy positions are derived from policy recommendations that underwent public consultation, and were reviewed by the Advisory Committee on Harmonized Construction Codes (ACHCC), and the analysis of feedback received through these consultations.

The focus of these policy positions is on operational GHG emissions, and policies that pertain exclusively to embodied GHG emissions will be addressed in late 2023 / early 2024. It is expected that this document will be supplemented to reflect relevant policy directions related specifically to embodied GHG emissions.

For clarity, the National Model Codes are enforced at the time of building permit application and there is no intent to incorporate requirements that would require benchmarking or other ongoing performance management programs or monitoring.


The National Model Codes currently contain an energy efficiency objective and related requirements for the design and construction of new buildings and houses. In the 2020 editions of the National Energy Code of Canada for Buildings (NECB) and National Building Code of Canada (NBC), energy efficiency tiers were introduced, containing measures that progressively increase energy efficiency and reduce the amount of energy needed to operate a building.

However, the National Model Codes do not presently address the type or quality of energy source used by buildings and houses nor do they address embodied GHG emissions.

In November 2022, the CBHCC adopted the direction set by the Canadian Commission on Building and Fire Codes, including:

  • developing objective(s) to address GHG emissions for inclusion in the 2025 National Model Codes;
  • developing proposed technical requirements related to operational GHG emissions for inclusion in the 2025 National Model Codes;
  • developing proposed technical requirements related to embodied GHG emissions for inclusion in the 2030 National Model Codes; and
  • undertaking policy work, and objective and technical development in parallel.

The goal of adding new objective(s) and technical requirements in the National Model Codes is to reduce GHG emissions due to buildings to help mitigate climate change and support achieving federal / provincial / territorial (FPT) climate goals. Approximately 27% 1 of Canada’s GHG emissions are due to buildings and so addressing GHG emissions in the Codes is an important step to enable action towards climate goals. Furthermore, achieving long term climate goals requires early policy action on operational GHG emissions that are over the longer term.

The National Model Codes can support the FPT aspirational goal of net zero emissions for buildings, however, it should be noted that carbon offsets and credits are not being considered within the scope of the Codes.

Policy Positions

The CBHCC recommends the following working definitions be used to inform the development of code requirements:

A zero or near zero operational emissions building or house is designed and constructed to eliminate or minimize operational GHG emissions through energy efficiency and energy source choice.

Emission factors represent the GHG emissions of energy sources (in carbon dioxide equivalent – CO2e – produced per unit of energy consumed).

Operational GHG emissions are related to the amount of energy consumed and the emissions factor of the energy source used to operate a building. Operational GHG emissions are described as scope 1 or scope 2 emissions, per the below:

ScopeDescriptionEquipment examples
1 (direct)GHG emissions that are produced from fuels that are combusted on site, primarily from combustion of hydrocarbons, e.g. fossil fuelsNatural gas / propane / oil and solid fuel appliances; CHP system; gas engine heat pump.
2 (indirect)GHG emissions that are produced from energy sources that are generated off site, e.g. purchased electricityElectric equipment, equipment that uses purchased energy, district heating or cooling.

Interplay between Codes and federal / provincial / territorial policies, programs and targets on reducing GHG emissions
A research project initiated to analyze the interplay between Codes and federal / provincial / territorial (FPT) policies, programs and targets on reducing operational and embodied GHG emissions concluded that:

  • There are many emissions-mitigation-focused policies across FPT jurisdictions in Canada, with those affecting buildings or houses accounting for about a third of total policies.
  • The majority of policies are voluntary (e.g. subsidies) and target the existing building stock.
  • The mix includes both broad and narrow (targeted) policies.
  • Very little policy is directed at embodied emissions.
  • Building codes have an important role in creating a minimum standard, and complement existing policies and fill policy gaps.

Recommendation: Given the foundational nature of the National Model Codes in building design and construction, they are appropriate instruments to reduce operational and embodied GHG emissions of buildings and houses and complement other policy instruments, such as energy policies and emissions policies, to support FPT climate goals.

In terms of timing, it is recommended that:

  • operational GHG emissions technical requirements be introduced in the 2025 version of the Codes;
  • embodied GHG emissions technical requirements be introduced in the 2030 version of the Codes; and
  • this work will inform the application to alterations to existing buildings, which will follow.

This timing reflects previous discussions of the CBHCC and recognizes that there is still work to be done on embodied GHG emissions (e.g., on advancing low-embodied GHG emissions materials) before technical solutions can be proposed. The timing also takes into consideration that energy efficiency measures when undertaking alterations to existing buildings are being proposed for introduction in the 2025 Codes and so operational and embodied GHG emissions for this application should follow.

Guiding principles and ultimate goals
Harmonization within a flexible framework

Code requirements for new houses and buildings towards zero or near zero operational GHG emissions solutions are needed in order to help support provincial, territorial and federal GHG emissions reduction targets and climate action plans.

Similar to the energy efficiency tiers, there are several advantages to a tiered approach as P/Ts move towards a low-carbon economy, including:

  1. providing a flexible approach to address P/T-specific circumstances (e.g. cleanliness of electricity grids, availability of clean fuels), and
  2. informing and moving the Canadian industry forward through the learnings and experience of early P/T adopters of the higher performance requirements as jurisdictions harmonize towards a goal of zero or near zero operational emissions.

Recommendation: That a tiered framework be developed in the NECB and NBC, with tiers progressing to zero or near zero operational GHG emissions.

Recommendation: That GHG emissions requirements be separate from the NBC and NECB energy performance tiers but developed with the view to not preclude pairing the requirements in various ways.

On addressing regional factors, the tiered approach will provide some flexibility to address different energy source issues as P/Ts will adopt solutions appropriate for their energy mix and could also choose different levels for different regions within their jurisdiction. The need for administrative requirements will be assessed as the development of technical solutions progresses.

Scope of operational GHG emissions requirements
The CBHCC considered the benefits and drawbacks of addressing only scope 1 emissions compared to addressing both scope 1 and scope 2 emissions in the National Model Codes, including that addressing only scope 1 emissions could lead to design choices that do not reduce GHG emissions overall, and has considered the benefits and drawback of various approaches to establishing emissions factors that capture the variability of grid-level (scope 2) emissions.

Recommendation: That both scope 1 and scope 2 emissions (i.e. all fuel types) be addressed to give a more realistic assessment of the GHG emissions emitted by a building.

Recommendation: That standardized and fixed emissions factors for the purpose of demonstrating compliance with GHG emissions provisions be set for each province/territory based on Environment and Climate Change Canada data, and if available, data from the provinces/territories that is specific to each province or territory, with the potential to evolve the approach to consider the impact of other policies and programs on GHG-emission trends over time. Given the complexity and policy implications of emissions data, provinces/territories may need to engage several provincial/territorial ministries in determining standardized emissions factors that are specific to each province/territory.

Compliance paths
For any chosen target, compliance options could include:

  • performance path(s) – using energy modelling software to demonstrate compliance to specific targets and/or;
  • prescriptive path(s) – using acceptable solutions that are deemed to reach specific targets.

To continue to allow flexibility in design and construction for housing and small buildings, both a performance path and a prescriptive path could be made available in the NBC. Prescriptive requirements in the NECB would also be useful for buildings that are designed without undertaking energy modelling.

Recommendation: That both performance and prescriptive options be developed in the NBC and in the NECB.

A variety of metrics could be used to assess the operational GHG emissions associated with buildings. For example, the tiered framework could use reference-based metrics, intensity-based metrics, absolute metrics, or a combination of two or more metrics.

  • A reference building metric sets a threshold for the allowable amount of GHG emissions for a proposed building compared to a reference building (expressed as a percent GHG emissions less than or equal to the reference building).
  • An intensity-based metric sets a threshold for the amount of allowable GHG emissions per floor area of the building (expressed in kg CO2e/m2/year).
  • An absolute metric sets a threshold for the amount of allowable GHG emissions per building (expressed in kg CO2e per building). An absolute metric does not normalize for building size, enabling designers/builders to decide on trade-offs between fuel sources/equipment, energy efficiency measures and building design/size.

Recommendation: That metrics be carefully considered to advance GHG emissions reduction goals.

Adoption and implementation considerations, including affordability
Implementation of new GHG emissions objectives and requirements will result in increased commercial activity in the construction sector, supporting a low-carbon economy while helping to achieve GHG emissions reductions goals. Federal, provincial or territorial and local or municipal policies already in place or planned support building industry capacity and provide a comprehensive a framework to promote decarbonization and capacity building. Further capacity development needs will be met by private training facilities, unions, postsecondary institutions, associations and manufacturers offering training for workers to gain low-carbon skills and knowledge.

The CBHCC’s dialogue with the Advisory Council will continue to highlight the implementation needs of interested parties and approaches for implementation by authorities having jurisdiction.

Affordability is an important policy consideration when developing building code requirements related to GHG emissions. As is typical, impact analysis that considers costs and benefits of the proposed code changes will be assessed in the technical development of requirements meeting the goals.

As well, ongoing operational energy costs savings can be realized by prioritizing energy efficiency. Optimization of energy tiers and GHG tiers within the P/T context should be a consideration in adoption.

Flexibility in compliance options, such as offering various compliance paths including performance based compliance options as recommended above, can also impact affordability. For example, performance paths can encourage innovation in building design and construction and provide designers with more options to comply with the Codes cost-effectively.

1 18% operational GHG emissions including electricity-related emissions (source: Natural Resources Canada (2022). The Canada Green Buildings Strategy) and approximately 9% embodied GHG emissions (global estimate) (source: United Nations Environment Programme (2022). 2022 Global Status Report for Buildings and Construction: Towards a Zero-emission, Efficient and Resilient Buildings and Construction Sector).