Geothermal technology on the rise in residential developments
By Megan HoeglerConstruction
High upfront costs have traditionally led developers to shy away from geothermal technology to heat and cool residential developments. But advancements in technology and a demand for sustainable building methods is recalibrating this way of thinking.
“Technology is advancing,” said Adel Esayed, dean of the Centre for Construction and Engineering Technologies at Toronto’s George Brown College. “As a result, customers want to see that reflected in their homes.”
Birchcliff Urban Towns, a new townhouse development in Toronto’s east end, exemplifies that mindset change. The project includes 52 townhouse units in a U-shaped two-storey building that’s tied together through a central courtyard. A geothermal system will heat and cool the development, which is currently under construction at Kingston Road and Birchcliff Avenue.
“There’s been a big shift towards sustainability, so developers are starting to say ‘Hey, this is something we can use as a marketing tool,’” said Lane Theriault, president of Subterra Renewables, a Toronto-based green energy supplier working on the Birchcliff Development. “I can think of 100 or so buildings in the Golden Horseshoe that use geothermal and were built in the last 10 years.”
Geothermal uses the ground as a source for transferring heat between the earth and the building. In doing so, Esayed noted, the geothermal systems use very little energy, reducing a building’s GHG emissions by up to 80 per cent.
“It has a much lower operating cost than other systems,” Esayed added. “Geothermal heating pumps can save customers between 35 to 60 per cent on their heating and 25 to 50 per cent on cooling compared to a conventional heating and cooling system.”
The greatest drawback is the steep installation cost. To install geothermal pipes, boreholes must be dug anywhere from 60 to 250 metres (200 to 800 feet) below ground. Depending on the size of the site, system size, accessibility and how much drilling is required, geothermal installation can cost anywhere from $10,000 to $30,000.
“What determines how deep you go is the cost of the drilling,” Theriault said. “What a lot of people don’t understand is that the first part of the hole, the top layer, is actually the most expensive to dig through. Because that’s where all of the clay and sand is, because it’s prone to caving, you have to case that part of the well.”
It also requires a certain level of skill to install.
“Sizing, design and installation of geothermal requires pro expertise for the most efficient system,” Esayed said. “It’s still relatively new, so there are fewer installers and less competition, this is why installation prices for geothermal are still so high.”
While it may be expensive to install, geothermal costs next to nothing to run. “Once it’s installed, it’s basically free energy,” Theriault said.
“Conventional equipment is sort of the opposite—cheap to install but very expensive to run,” he added. “They use a lot of energy, they break down a lot and you’ve got to replace them. With geo, once it’s in the ground, it sort of lasts forever.”
According to Birchcliff Towns’ general contractor, John Wyman, there are currently 10 workers on site. He anticipates the build will need between 30 to 40 workers as it progresses into the later stages.
Cast-in-place concrete is being used for the below-grade portion of the building, including the underground parking lot, while crews are using conventional wood frame construction for the rest of the complex.
The development will be free of natural gas as well as rooftop heating and cooling units, eliminating a noisy eyesore, Theriault noted. Instead of rooftop heating and cooling units, each suite will have a mechanical box connected to a two-in-one heating and cooling pump.
Construction on the Birchcliff Development began in June 2019. The current completion timeline is set for the end of 2020.