In 2020, 240 Markland Drive, a mid-rise multi-unit residential building (MURB) located in Etobicoke, Ontario, underwent a transformative retrofit. Originally built in 1964, the 10-storey residential building has a 12,557 m² gross floor area and consists of 113 units. Years of insufficient capital investment led to outdated systems and deteriorating materials, impacting the building’s performance and tenant comfort.

After acquiring the property in August, 2020, Carttera saw an opportunity to undergo a deep energy retrofit of the 60-year-old MURB. A two-year deep retrofit was completed in July 2022, involving extensive changes to revitalize the building. These changes enabled 240 Markland Drive to achieve Zero Carbon Building™ – Performance certification in 2023, highlighting a milestone in environmental responsibility for both Carttera and the community.

The growing market demand for sustainable real estate as well as Carttera’s commitments to environmental, social, and governance (ESG) principles drove the idea to retrofit the building to achieve zero carbon operations. Certifying under CAGBC’s ZCB-Performance Standard would align with Carterra’s commitment to responsible and sustainable business practices, while mitigating future risks associated with climate change and regulatory pressures.

Retrofitting an older building for zero carbon performance

To achieve ZCB-Performance certification, a well-planned and executed sustainability strategy was essential to guide the retrofit of the outdated building towards energy efficiency and sustainability.

One of the biggest challenges was the logistics and coordination of the energy efficiency program with the execution of various urgent repairs that were needed, like the replacement of a leaking roof. Balancing construction sequencing with current tenants, the pandemic and pandemic-related supply chain issues also factored in as Carttera worked to balance daily operational needs of a fully tenanted building. 

Carttera’s approach to the retrofit focused on several key areas to meet certification requirements. First was the prioritization of energy-efficient systems and technologies throughout the building, including a geothermal system for heating and cooling, ENERGY STAR appliances, high-efficiency lighting with motion sensors, and improved insulation and windows to minimize energy consumption. The roof was upgraded with 4” ridged insulation to achieve R-20, and new double pane argon-filled windows with low e-coating were installed, resulting in an improved overall performance of the glass and frame. The building envelope performance was enhanced with an exterior insulation finishing system to reduce air infiltration and energy loss. This exterior wall cladding system added 3” of insulation over the existing brick system with 1.7” of Expanded Polystyrene (EPS) insulation, achieving a total effective performance of R-12.8 according to thermal bridging calculations.

The enhanced building envelope and energy systems improves the passive survivability, or resilience, of the building to endure a two-day power outage while maintaining occupant comfort.

One of the most significant and quantifiable achievements of the completed retrofit was the reduction in electricity usage in building operations and the overall demand on the electrical grid. Replacing the electric baseboards with Ground Source Heat Pumps (powered by a Geo-Exchange Field) improved overall energy efficiency and drastically reduced the building’s reliance on electricity for heating and cooling. To ensure future proofing of the system, the Geo-Exchange Field has been designed with capacity to accommodate the future replacement of the rooftop Makeup Air Unit (MUA). This upgrade provides an enhanced central Energy Recovery Ventilator (ERV) with 76 percent sensible recovery and 51 percent latent recovery efficiency. Real-time data reflects a 50% reduction in electricity use.

Aligned with Carttera’s commitment to sustainability and forward-thinking urban development, the renovation of 240 Markland improved resident’s quality of life, providing access to space cooling for all 113 units, offering increased comfort, particularly for the senior community residing in the building.  

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The improvements to the building’s envelope allowed us to reduce the size of the new geothermal heat pump system and the associated cost of the geothermal field. The building upgrades drastically reduced energy and carbon emissions, as well as improved indoor air quality and thermal comfort for the residents.

Micheal Guadagnoli, Director of Building Performance, Ecovert

A benchmark for future MURB retrofits

240 Markland Drive is an example of revitalized sustainability. Pursuing the retrofit of the building was an opportunity for Carttera to implement new strategies such as prioritizing operational efficiency, green initiatives, and applying a forward-thinking approach to existing building projects.

Continuing to prioritize and apply these strategies on future MURB retrofits will help ensure long-term benefits such as lower building energy consumption and operational costs and enhanced tenant satisfaction. Certification using ZCB-Performance not only validates these initiatives but also offer tangible benefits such as improved building resiliency, lower operational costs and an award that a tenant can be proud of in a building they call home.

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Certifying under CAGBC’s ZCB-Performance Standard validates and reinforces the post-retrofit performance results for not only Carttera but also the residents and potential future investors.

Christina Basan, Partner, Development, Carttera