The climate crisis demands innovative approaches to reduce carbon emissions, and Canada is rising to the challenge. The Canada Green Building Council (CaGBC) has introduced the Zero Carbon Building (ZCB) standards, a pioneering framework designed to decarbonize Canada’s building sector and help meet the country’s climate commitments. These standards offer a roadmap for creating energy-efficient, low-carbon buildings that minimize greenhouse gas emissions. But what exactly does it mean for a building to achieve zero carbon, and how do the ZCB standards support this transition?
What is a Zero Carbon Building?
A Zero Carbon Building (ZCB) is one that operates with extremely high energy efficiency, drastically reducing greenhouse gas (GHG) emissions. Emissions from both building materials and operations are addressed. Although the goal is to eliminate emissions completely, buildings can use high-quality carbon offsets to counterbalance any remaining emissions that cannot be eliminated through design and operational measures.
The Role of the ZCB Standards
The ZCB standards set rigorous but flexible criteria for designing, building, and retrofitting buildings to operate with minimal environmental impact. These standards recognize the growing importance of decarbonizing Canada’s building sector and offer guidance for reducing carbon emissions throughout a building’s lifecycle. Whether it’s a commercial office, multi-unit residential building, arena, or warehouse, buildings of all types are eligible to pursue Zero Carbon Certification.
Key highlights of the ZCB standards include:
- Energy Efficiency: Buildings must focus on reducing their overall energy use, typically by improving thermal performance and mechanical systems.
- On-Site Renewable Energy: Projects are encouraged to generate renewable energy on-site (e.g., solar or wind) to meet a portion of their energy needs.
- Embodied Carbon: In addition to operational emissions, the ZCB standards also address the embodied carbon found in building materials, encouraging low-carbon materials and sustainable construction methods.
- Carbon Offsets: For any emissions that remain after all energy efficiency and renewable energy measures, high-quality carbon offsets can be purchased to achieve net-zero carbon.
Two Pathways to Certification
The ZCB Standard offers two distinct pathways, depending on whether the building is in the design or operational phase:
- ZCB-Design Standard: This pathway is focused on guiding the design of new buildings or retrofits of existing structures. The goal is to ensure that buildings can achieve zero carbon emissions once in operation. This standard sets the framework for incorporating energy-efficient systems, renewable energy, and low-carbon materials at the design stage.
- ZCB-Performance Standard: For existing buildings, the ZCB-Performance Standard certifies that the building operates with zero carbon emissions. It requires ongoing verification and reporting to ensure that buildings maintain their zero-carbon status, typically reviewed on an annual basis.
Zero Carbon Building – Design Standard
The ZCB-Design Standard is tailored for new construction and major retrofits, guiding project teams in designing buildings that can achieve zero-carbon emissions once they are operational. By incorporating renewable energy, energy-efficient systems, and low-carbon materials, this standard ensures that buildings are set up for long-term sustainability.
Key Requirements:
- Zero Carbon Balance: The design must model the building’s carbon emissions and demonstrate a zero-carbon balance, ensuring that anticipated energy use is offset or minimized through design features.
- Embodied Carbon and Refrigerants: Designers must consider and limit the embodied carbon from construction materials as well as address the environmental impacts of refrigerants in HVAC systems.
- Energy Efficiency: Teams can choose approaches to meet energy efficiency goals, ensuring that the building performs at a high level while minimizing operational carbon emissions.
- Airtightness and Resiliency: The building’s airtightness must be evaluated, and a future-weather sensitivity analysis should be conducted to ensure the building can withstand changing climate conditions.
- Transition Plan for Onsite Combustion: If combustion-based systems (e.g., for heating water) are used, a costed plan must outline how these systems will transition to non-combustion alternatives over time.
Released in June 2024, ZCB-Design v4 includes updates that set more stringent limits on onsite combustion for space heating and hot water, driving the market towards greater electrification and reduced reliance on fossil fuels.
Zero Carbon Building – Performance Standard
The ZCB-Performance Standard focuses on existing buildings, ensuring that they eliminate or offset all carbon emissions associated with their operations. This includes emissions from heating, cooling, and electricity, as well as from refrigerant leaks and embodied carbon from new construction materials.
Key Requirements:
- Zero Carbon Balance: The building must achieve a zero-carbon balance through operational efficiency, the use of renewable energy, and carbon offsets.
- Energy Efficiency: Buildings must track and report their Energy Use Intensity (EUI) and seasonal energy demand peaks.
- Embodied Carbon and Refrigerants: Any emissions from embodied carbon (associated with materials like concrete and steel) and potential refrigerant leaks must be accounted for through high-quality carbon offsets.
- Onsite Combustion Transition Plan: If the building uses combustion equipment (e.g., gas boilers), a transition plan must be in place to phase out combustion over time.
This pathway ensures that building operations are regularly reviewed, with performance data updated annually. Buildings that adhere to this standard are able to demonstrate a clear commitment to minimizing their climate impacts while maintaining efficient, cost-effective operations.
Why Pursue Zero Carbon Certification?
Achieving Zero Carbon certification offers numerous benefits, including:
- Improved Resiliency: Buildings designed to the ZCB standards are future-proofed against rising energy costs, regulatory changes, and shifting environmental conditions.
- Increased Access to Capital: Certification can unlock access to green bonds, loans, and federal incentives that support the construction or retrofitting of energy-efficient, low-carbon buildings.
- Market Leadership: Zero carbon buildings signal to tenants, investors, and the public that sustainability and climate action are core values of the organization.
The shift to zero-carbon buildings is essential for achieving Canada’s climate goals, and the CaGBC’s ZCB standards provide the tools needed to make that vision a reality. Whether you’re operating an existing building or designing a new one, the path to zero carbon is not just possible—it’s imperative for a sustainable future.
Unlocking Capital and Funding for Zero Carbon Buildings
Governments and investors are increasingly supporting the decarbonization of buildings, recognizing that it’s key to achieving national climate goals. Achieving Zero Carbon Building Certification opens the door to financing opportunities such as green bonds, sustainability-linked loans, and mortgages. There are also federal tax incentives, rebates, and grants available to support the construction or retrofitting of zero-carbon buildings. These include programs from:
- Canadian Mortgage and Housing Corporation (CMHC): MLI Select
- Federation of Canadian Municipalities (FCM): Green Municipal Fund (GMF)
- Government of Canada: Green and Inclusive Communities and Buildings (GICB)