25-55 St. Clair Ave. E in Toronto – owned by Public Services and Procurement Canada – will serve as a model for deep energy retrofits once construction is complete, reducing the building’s greenhouse gas (GHG) emissions by 82 per cent.

The 11-storey Arthur Meighen building – originally built in the 1950’s – will become one of Canada’s first federal carbon-neutral buildings.

Markham, Ont.-based BGIS is the project leader, while DIALOG handles the architecture and Urbacon is working as construction manager. The latter two companies were awarded their contracts in 2017, with the project beginning in July 2018.

“The result here is this: This older building is now predicted to outperform the highest standards of the Toronto Green Standards. So old becomes new again, the community gets revitalized and re-energized,” said Charles Marshall, a partner at DIALOG who used 25-55 St. Clair as a case study for deep energy retrofits during his recent presentation at the Green Building Festival in Toronto.

Editor's Note: This is the first of three projects featured at the Green Building Festival which SustainableBiz will chronicle in a mini-series over the next few days. Part II features a project at the Univ. of Calgary

“We achieve these performance results, including a low-energy use intensity and upwards of 60, 80 per cent savings in energy and GHG (versus) the pre-retrofit conditions.”

Once complete, the building will accommodate staff from several government departments and agencies, including Canada Revenue Agency, Canada Border Services Agency as well as the Immigration and Refugee Board. Approximately 1,500 federal employees will work in the building.

The base building will be complete in spring 2023, and fully complete that summer with the tenants to move in by the fall. The project has created over 300 full-time construction and consultancy jobs during its four-year duration.

25-55 St. Clair rehabilitation project

All building systems, including electrical, plumbing, mechanical, heating, ventilation and HVAC are being replaced.

That 80 per cent in energy savings will work out to a reduction of 700 tonnes of GHG per year. The building is forecast use 72 kW-h per square metre each year.

Upgrades include a geothermal system – 58 ground source boreholes drilled 150 metres under the existing parking garage. 

“These projects are possible with the right dedication, the right buy-in and the right objective set,” Marshall said.

Occupancy sensors and smart metering will assist with reducing energy use. As well, a basement cistern will collect rainwater from the roof to reuse in the building’s mechanical systems.

The building will utilize 850 solar photovoltaic panels generating 348 mW-h per year, providing 15 per cent of total energy use and reducing GHG emissions by 15 tonnes annually.

“This is probably the lowest TEDi (thermal energy demand intensity) building that we’re currently working on, but the predicted TEDi is about 15 kilowatt hours per square metre per year,” he said. “So the specific technical solutions may vary, but getting those heating-cooling loads absolutely down is absolutely critical.”

Bird-friendly glazing will be implemented on the first 12 metres of building height – to prevent bird strikes with windows and reflective surfaces.

There will be bicycle storage lockers and showers, as well as easy access to the TTC. Over 40 electric vehicle charging stations will be installed.

Embodied carbon in the building

Also noted was the reuse of existing concrete and steel structures. Marshall discussed a lifecycle assessment of the building that revealed up-front carbon amounts for 91 per cent of total embodied carbon emissions. Reusing those structures saves about 75 per cent – 7,800 tonnes of carbon – in the building.

“These projects are strategic, it really requires careful analysis of a building and scenarios to identify the right solutions, that almost inevitably requires deeper investment and recapitalization of the building,” Marshall told the festival audience.

As he told SustainableBiz in a later interview, the construction industry is risk-averse. Having shown that certain net-zero technologies have been de-risked, his hope is for 25-55 St. Clair and other buildings featured during his festival presentation to become more commonplace over the years as Canada continues moving toward its net-zero goals.

"We're trying to get to a 37 per cent reduction in the buildings sector by 2030. I'm an engineer, so I'm a big fan of simple math," he explained. "But how do you get to 37 per cent? Well, you go find half the buildings, because that's probably as many as we could possibly get to, and you retrofit them by 75 to 80 per cent."

"Then you would get to your 37 per cent right?"