Green Buildings: How and Why to Build Them

Written by: Tessy Schreyer

Edited by: Ashley Yeung

Junior Division

Green Buildings

The term “Green Building” may evoke a picture of a building covered in plants, with solar panels or a garden on the roof. While buildings like this do exist and may qualify as a “green building”, many green buildings look just like any other building on the block. There are many strategies to make a building “green” - in other words, sustainable or environmentally responsible. Using sustainable strategies has been institutionalized as nations have created certifications to recognize and, in some cases, award sustainable building efforts. Moreover, sustainable building initiatives are being carried out in many places with and without certification. Sustainable projects, for new builds and retrofitting, aim to bring awareness to buildings’ consumption and reduce their impact on the environment in a time where many building users are distanced from the impacts of their constant use.

Why is sustainable building relevant?

In Canada, the building sector is the third-highest emitting sector (Natural Resources Canada, 2024). Globally, the built environment sector, which includes the construction and operation of buildings, produced 37 per cent of greenhouse gas emissions in 2022 (Dyson et al., 2023). Building emissions are quite alarming, but also represent an area of great potential to reduce global emissions. Although non-conservative energy consumption behaviors represent a large portion of building emissions, buildings can be deliberately constructed from sustainably-sourced materials to reduce the buildings’ energy consumption without the user changing their behavior. If a building is built using technologies and materials that are thermodynamically inefficient and sourced from energy-intensive processes, energy is wasted, whether or not the user wishes for this to happen. This is the essence of green buildings: changing user behavior is a bonus, but the real work is being done by the buildings themselves. Capitalizing on this opportunity to reduce building emissions that were previously ill accounted for, sustainability practices and standards pave the way for old buildings to be retrofitted or new builds to be constructed in more energy-efficient ways. Optimally, a sustainable building would require as little energy as possible while in use, obtaining the energy it does need from renewable sources.

What strategies can be used to make a building “sustainable”?

Reducing Embodied Emissions and Location Selection

Building designers can approach sustainable building from many angles and likely will use a combination of strategies rather than just one in order to align themselves more broadly with sustainability's diverse goals. Methods can adopt a ground-up approach to the project through the use of a life cycle assessment (LCA). An LCA is a tool used to inform builders of the “energy use and other environmental impacts associated with all life cycle phases of a building: raw material procurement, manufacturing, construction, operation and decommissioning” - the impacts from the building’s “birth” to “death” (Read, 2021).

Before a building is even “born” it can be made more environmentally conscious by prudently considering where it will be constructed. The more connected the location is to public transportation and other systems of mobility, the lower the users’ emissions will be from their journeys to and from the building. The location is also tied to what the building will replace when it is built. If it replaces an old energy-intensive building, it has the potential to reduce energy use, but if it will impede upon untouched nature, it will inevitably increase emissions because the land use changes from undisturbed to occupied (Davidson, 2014). Although at times, buildings must encroach on unused spaces, optimizing land use is one way builders can be less environmentally destructive.

Once a location is set, the materials used to build the structure can be accounted for by evaluating the materials’ embodied carbon: the amount of greenhouse gas emissions produced by the manufacturing, transport, and construction of a material (Natural Resources Canada, 2024). For example, using locally sourced timber, rather than plastics from a country an ocean away, can reduce the transportation required to obtain the product. Further, using products that are produced or extracted in less energy- and water-intensive ways will also lower the embodied carbon of building materials.

There are several emerging innovations proven to reduce the embodied carbon of construction materials. The most suitable choice of sustainable material will vary depending on locality and the means of production used to extract it. Earth, wood, hemp, cork, and clay all require less energy to be extracted, lowering their embodied carbon if sourced sustainably (Read, 2021). Often, these same resources can be purchased locally. Recycled steel can be used in “structural and framing elements, roofing,” and siding, provided it meets the relevant grade requirements, but it does have a higher embodied carbon footprint (Read, 2021). Another general approach involves producing materials and parts that can be recycled and repaired, to eliminate the future need to harvest replacement resources. While there are numerous existing sustainable material options, engineers are still working to find cost-effective solutions that function for projects of all kinds on a grander scale.

Reducing Operational Emissions and Resource Use

Materials choice can also help reduce a building's operational emissions - the emissions it produces when it is in use - by partially regulating the thermal envelope. In Canada, 96% of operational emissions are produced from space and water heating (Natural Resources Canada, 2024). Hence, regulating building temperature without consuming energy is one key way that materials can significantly reduce energy consumption. At times, these materials can also be sourced sustainably. The use of stone walls is one simple way to regulate temperature that has been used for centuries. Stone is effective at absorbing large amounts of heat, and it releases this heat back out slowly. In this way, it regulates internal temperature without requiring air conditioning, or at least reduces the need for it throughout the day (Julien, 2019).

Another tool is the implementation of phase change materials (PCMs) in insulation. PCMs can store heat, but when the surrounding environment heats up, they change phase, absorbing heat from their surroundings, and producing a cooling effect. The opposite occurs when the building cools down, as PCMs condense and release heat. PCMs exploit thermodynamics to adapt to temperature with no human intervention (Julien, 2019).

An alternate method involves careful placement and design of windows. While sufficient natural lighting significantly contributes to a positive atmosphere in a building, windows have the potential to let a lot of hot or cold air in, which can be taxing on air conditioning systems. Using glazed windows - windows with several glass panel layers - can help mitigate this. The glass panel layers have gas in between them, which heats and cools with the temperature outside, rather than allowing temperature fluctuations indoors (EWI Store, 2024).

A final temperature regulation technique is the use of plant coverage on the roofs or sides of a building. Green roofs prevent buildings from heating up by lowering surface and air temperatures, reducing the need for air conditioning. If implemented on a larger scale, green roofs can contribute to temperature reduction across a city. Further, they have additional benefits as they sequester carbon dioxide and reduce runoff during precipitation events (US EPA, 2014).

A crucial step in building construction is addressing how to meet the demand for energy. What makes buildings most environmentally detrimental in their operation is the burning of fossil fuels to provide electricity, especially for heating and cooling. Producing energy with renewable resources and installing electrical appliances in buildings can help immensely to alleviate the consumption of fossil fuels. A building connected to a grid fueled at least partially by renewables - or that can produce its own energy with renewable technologies on site - can easily reduce its fossil fuel consumption. Additionally, the use of electric heat pumps to heat and cool buildings rather than the use of systems reliant on natural gas, propane, or oil is a simple and cost-effective alternative (Natural Resources Canada, 2024). Being critical of where buildings obtain their energy supply is crucial to complement efforts to reduce energy consumption overall.

Also tied to buildings' environmental impact is the high consumption of water. Low-flow water fixtures can be installed in appliances like toilets, shower heads, and sinks. Leaks in existing appliances can be repaired to reduce consumption. More intense measures include rainwater collection or the re-use of grey water. Grey water is tap water soiled by use from appliances like sinks, showers, and washing machines that is no longer entirely purified but not toxic. Grey water can be recycled if buildings have proper systems to clean and recirculate it before sending it off to the sewers (Spigarelli, 2012).

Overall, there are seemingly endless technologies, materials, and strategies that can be employed to make a building less consumptive in nature. Adoption of these strategies may be motivated by benevolence towards the environment, cost-saving goals, or aims to attain sustainable building certification in a given region - a title which often offers monetary benefits.

What does it mean to be a certified green building?

Sustainable buildings can take many forms, and may exist with or without recognition. That said, labeling buildings as ‘sustainable’ is often of interest to policymakers. It is also helpful, in policymaking and beyond, to set standards and metrics when discussing such a robust topic. One widely recognized standard which is used internationally to evaluate and certify buildings based on their energy efficiency and environmental impact is Leadership in Energy and Environmental Design (LEED) (Deisy, 2025).

 Developed and released by the U.S. Green Building Council (USGBC) in 1995, LEED is utilized in more than 167 countries, allowing for cross-country comparisons and translatable sustainability achievements (LEED, ENERGY STAR, 2023). There are several other metrics, with similar goals to LEED, to certify or encourage green building construction or retrofitting, all of which represent valuable sustainability efforts.

 LEED is a certification system based on points, so it is highly quantitative. There are four levels of certification: certification, silver, gold, and platinum. “Certification” requires the fewest points, and “platinum” requires the most. The program considers how a building is designed to bolster sustainable site use, water conservation, energy efficiency, materials and resource conservation, and indoor environmental quality (Kubba, 2010). ‘Sustainable site use’ pertains to limiting the building's impact on the surrounding natural area on which it is built. It was created to include an assessment of the environmental changes a building imposes on the surrounding environment and encourage construction to mitigate any effects (Makous, 2017). Oftentimes, LEED certified buildings are created with the goal to maximize the well-being of users while minimizing the building’s environmental impacts. That is, if the goal is to construct buildings to protect the environment for future generations while creating a pleasant space for current users (CAGBC, 2013).

The goals of LEED all attempt to make buildings more sustainable by minimizing their energy and water use and their embodied and operational carbon. A building can achieve LEED’s goals, or perform better, even if certification is not sought after or attained. Furthermore, because of the novelty of LEED, studies are still attempting to verify that in-use LEED buildings genuinely reduce energy consumption of a building relative to their conventional counterparts (Newsham et al., 2009). LEED is just one metric by which sustainable buildings are measured, and though it may not be perfect, it has amplified sustainability agendas and provided a quantitative basis to encourage and track sustainability efforts.

Where does Canada stand in terms of sustainable building?

  While several building sustainability metrics and systems exist simultaneously in Canada, LEED is promoted by the Canada Green Building Council (Baker & McKenzie LLP, 2023). In fact, the country prides itself on its sustainable building efforts - in 2023, Canada ranked number two globally in its amount of LEED certified buildings (LEED, ENERGY STAR, 2023). There are almost 3,000 LEED certified projects in Canada (Green Business Certification Inc., 2015). Voluntary adherence to LEED standards by builders as well as federal and provincial market-based incentives to strive for LEED certification, make this level of commitment achievable. Additionally, ‘going electric’ or using renewables can have lower operational costs, which motivates owners to opt for sustainable choices on their own. Despite Canada’s high standing in sustainable construction, an important point to be noted is that Canada made up 1.5% of global emissions in 2022 despite making up only around 0.5% of the global population, so there is still work to be done (International Energy Agency, 2023).

What about sustainable building in Montreal?

In the city of Montreal, numerous sustainable buildings have already been built, and many more are underway. The Saint-Michel Environmental Complex Soccer Stadium, completed in 2014, has a roof made entirely of wood structures that were assembled in northern Quebec. The complex, which has two soccer pitches and seating for events, has since obtained LEED Gold Status. Another sustainable building in Montreal is the Crémazie office building, constructed by the Société de transport de Montréal (STM). Operational since 2022, the building employs more energy-efficient heating systems, has white and green roofs, low-flow appliances, a recovered rainwater flush system, and is built with 26% recycled and 47% regionally sourced materials. These assets, among various others, contributed to the building's Gold LEED certification as of 2024. There is also Quebec's first Platinum LEED certified building: the Center for Sustainable Development. Located in downtown Montreal, the building boasts several sustainable features, including plants on the interior and roof, use of geothermal heat, and reused and eco-friendly materials. The center has been open since 2011 and even gives free educational tours to the public (Centre for Sustainable Development | Hydro-Québec, n.d.).

McGill University itself has a handful of LEED certified buildings, such as the Armstrong building and the Bellini Life Sciences Building, and the university’s Climate and Sustainability Strategy from 2025 to 2030 has stated that newly constructed buildings must be at least Gold LEED certified (Broekstra, 2023). In recent years, the municipality of Montreal has deployed subsidy programs to encourage businesses to construct or renovate sustainably and obtain certifications including LEED, Living Building Challenge, Passive House, Zero Carbon Building, and several others. The most recent subsidy program ended in 2024, however the city has put a new law into place requiring owners of large commercial, institutional, and multi-unit residential buildings to discipline their emissions (Montréal, n.d.).

These examples are non-exhaustive and sustainable building efforts continue to be carried out across the entire city. Whether or not a sustainable effort attains LEED certification, it contributes to the goal of reducing emissions and consumption from buildings. Projects as small as collecting rain water to water plants on a rooftop garden, to those as large as constructing an entire building from low carbon footprint materials, help to further sustainability goals and inspire others to act.

That said, sustainability certifications like LEED must still prove their tangible impact on reducing energy consumption. They must also balance several sustainability philosophies, while being refined and sometimes even entirely rebuilt to address areas in which they fall short. Further, sustainability certifications cannot change how the user chooses to consume, and they cannot solve superfluous energy, water, and material consumption that occurs as a result of user behavior and policy. Yet, these building sustainability strategies are a part of a much bigger picture of addressing increasing energy demand, particularly in the high-emitting construction sector, in a time when energy generation is still fueled in great part by fossil fuels.

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References

Baker & McKenzie LLP. (2023). Global Corporate Real Estate Guide 2023. https://www.bakermckenzie.com/-/media/files/expertise/real-estate/global-corporate-real-estate-guide-2023.pdf

Broekstra, N. (2023, April 17). Sustainability an integral part of construction and renovation at McGill. https://reporter.mcgill.ca/sustainability-an-integral-part-of-construction-and-renovation-at-mcgill/

Business Development Bank of Canada. (2023, December 21). LEED, ENERGY STAR and BOMA BEST: A guide to Canadian green building standards and certifications. BDC.Ca. https://www.bdc.ca/en/articles-tools/sustainability/climate-action-centre/articles/leed-energy-star-boma-best-more-guide-to-canadian-green-building-standards-certifications

CAGBC. (2013, January 9). Montreal’s LEED Platinum Centre for Sustainable Development. Canada Green Building Council (CAGBC). https://www.cagbc.org/green-building-showcase/green-building-spotlight/case-studies/leed_spotlight_2013_/

Centre for Sustainable Development | hydro-québec. (n.d.). https://www.hydroquebec.com/facility-tours/tours-general-public/centre-sustainable-development-montreal.html

Davidson, B. (Director). (2014). Green Buildings Are More Than Brick and Mortar [Video recording]. https://youtu.be/JEUShQ7r_tE?si=QWIIhWEUaNVPKSVT

Deisy, V. (2025, February 5). Italy and Turkey Represent Europe in the Top 10 Countries for LEED. Green Business Certification Inc. https://www.gbci.org/italy-and-turkey-represent-europe-top-10-countries-leed

Dyson, A., Keena, N., Lokko, M., Reck, B. K., & Ciardullo, C. (2023). Building Materials and the Climate: Constructing a New Future. United Nations Environment Programme.

EWI Store. (2024, July 15). What is a Thermal Envelope and Why is it Important? EWI Store Render Specialists. https://ewistore.co.uk/what-is-a-thermal-envelope-and-why-is-it-important/

Green Business Certification Inc. (2015). LEED in Motion: Canada. https://cloud.kapostcontent.net/pub/817bd9c8-85de-4b8c-8376-53f84e991469/leed-in-motion-canada.pdf?kui=slbMSwdJ87vzgz112TcVoA

International Energy Agency. (2023). Energy system of Canada. https://www.iea.org/countries/canada/emissions

Julien, A. (2019, August 9). How to keep buildings cool without air conditioning – according to an expert in sustainable design. Global Center on Adaptation. https://gca.org/how-to-keep-buildings-cool-without-air-conditioning-according-to-an-expert-in-sustainable-design/

Kubba, S. (2010). Leed practices, certification, and accreditation handbook. Elsevier, Inc. https://www.sciencedirect.com/science/article/pii/B978185617691000014X

Makous, D. (2017, November 6). Sustainable sites in leed v4 . U.S. Green Building Council. https://www.usgbc.org/articles/sustainable-sites-leed-v4

Mcgill Climate & Sustainability Strategy. (n.d.). Sustainability. https://www.mcgill.ca/sustainability/commitments/sustainability-strategy

Montréal, V. de. (n.d.). By-law concerning GHG emission disclosures and ratings of large buildings. https://montreal.ca/en/articles/law-concerning-ghg-emission-disclosures-and-ratings-large-buildings-20548

Natural Resources Canada. (2024, July 8). The Canada Green Buildings Strategy: Transforming Canada’s buildings sector for a net-zero and resilient future. Government of Canada. https://natural-resources.canada.ca/energy-efficiency/building-energy-efficiency/canada-green-buildings-strategy-transforming-canada-s-buildings-sector-net-zero-resilient-future

Nordic structures | nordic.ca | engineered wood | projects | structures | smec soccer stadium. (n.d.). https://www.nordic.ca/en/projects/structures/smec-soccer-stadium

Newsham, G. R., Mancini, S., & Birt, B. J. (2009b). Do LEED-certified buildings save energy? Yes, but…. Energy and Buildings, 41(8), 897–905. https://doi.org/10.1016/j.enbuild.2009.03.014

Read, M. (2021, April 30). Green Building Guide To Sustainable Materials. Green Building Canada. https://greenbuildingcanada.ca/green-sustainable-materials/

Spigarelli, M. (2012, March 16). 10 ways to save water in commercial buildings. Consulting - Specifying Engineer. https://www.csemag.com/10-ways-to-save-water-in-commercial-buildings/

US EPA. (2014, June 17). Using Green Roofs to Reduce Heat Islands [Overviews and Factsheets]. United States Environmental Protection Agency. https://www.epa.gov/heatislands/using-green-roofs-reduce-heat-islands