Harnessing one of earth’s great powers
Geothermal heating and cooling systems’ small carbon footprint makes fans of condo builders
After Dave de Sylva built a house for his parents in 1989 that incorporated a geoexchange system, he was astonished at how inexpensively it heated and cooled the home.
“My father worked all his life for Orenda Engines in Malton until his retirement in 1985. Shortly afterwards, he and I designed a little bungalow in the hamlet of Ashgrove,” de Sylva says of the early geoexchange house built for his folks, James and Angela, just south of Georgetown. Del Ridge Homes — the company de Sylva co-founded with George Le Donne — adopted the technology, starting with Appleby Woods condominiums in Burlington eight years ago. Del Ridge is now finishing its ninth geo-exchange building and the system has become a cornerstone of the company’s sustainable-building philosophy.
Geo-exchange takes advantage of the Earth’s constant below-ground temperature, about 10 C around the GTA. It uses the natural energy by boring holes hundreds of feet into the ground and installing liquid-filled loops of piping that are connected to heat pumps, used to concentrate the heat distributed by the building’s HVAC (heating, ventilation and air conditioning) system. Savings are estimated to be 70 per cent of current heating expenses. (Geo-exchange is often referred to as geothermal energy, which involves extracting heat as hot water or steam.)
While Del Ridge was one of the early adopters of geo-exchange for condos in Ontario, including its GreenLife buildings in Milton and Markham, more builders and developers are beginning to use the system, which has been around for about 30 years. Examples include Club Leisure’s TreeTops at Hidden Valley in Huntsville, Ont., City Corp. Development’s Harmony Village in Scarborough,
“The average consumption is $12 a month for heating and cooling.” DAVE DE SYLVA DEL RIDGE HOMES PRINCIPAL ON USING GEO-EXCHANGE ENERGY
the Molinaro Group’s Strata in Burlington and Castleridge Homes’ the Clairington in Brampton.
Geo-exchange systems typically use 40 per cent to 65 per cent less energy than those using fossil fuels; they also eliminate CO2 and greenhouse gas emissions. However, they are expensive to install and the electricity costs to run the heat pumps can be significant. So why are more builders investing in this energy source?
A major impetus is the change to build- ing codes and municipal rules directing “green” building, says AEC Consultants’ Greg Winokur, an engineer on multiple geothermal projects around the GTA.
“As of 2017, any new buildings in the province of Ontario are going to have to increase the threshold for energy efficiency,” says Winokur.
“Existing technologies are getting stretched to the limit. You can insulate a building as much as you can, put in as few windows as you can, but once you finish with the envelope, the usual mechanical systems don’t allow much more movement (in terms of increasing efficiency).”
Coupled with that, Winokur points to additional rules — such as the city of Toronto Green Standard on midrise and highrise residential buildings (four storeys or taller) and standards such as LEED (Leadership in Energy and Environmental Design) that encourage sustainable construction and reduction of CO2 emissions.
“Codes are putting pressure on the amount of carbon footprint a development can create and the province is pondering a carbon tax. There are a conglomeration of influences overtaking the consideration of natural gas (as a heating source),” says Winokur. “Gas prices are low, but people are doing it for other reasons.”
One is peak demand for electricity and geo-exchange can reduce that demand, says Winokur. He says while the heat pumps needed for geo-exchange systems do use electricity, it’s used efficiently.
“We find that when the system is in cooling mode, 85 per cent of the energy use is renewable, with 15 per cent coming from electricity driving the heat pumps,” he says. “In heating mode, about 90 per cent comes from energy stored in the ground and 10 per cent from electricity. They maintain constant, comfortable temperatures and don’t have peaks, so you reduce peak demand on the grid.”
Vince Molinaro, president of the Molinaro Group and current president of the Ontario Home Builders Association, says his company’s decision to use geo-exchange “started with us wanting to do more sustainable projects and construct LEED buildings — and geo-exchange followed.” They used it in their 186-unit Strata, a LEED condominium in Burlington, and in a project they’ve retained as a rental building.
With Strata, “we had a good consultant and it was a calculated risk, but we couldn’t justify adding the cost of the field (the area below the earth required to source the heat),” says Molinaro, estimating the cost would mean the condo units would be priced about $10,000 to $20,000 more than competing projects. So Molinaro entered into a 30-year agreement with Ameresco Canada, a renewable energy management company, to install and manage the system at a cost of about eight cents a month per condo owner. Strata, a luxury building, has been occupied for two years and is a sought-after address for resales.
“The electrical costs are higher than compared to a building heated by natural gas, but you have to look long-term and over the full life cycle of the building, there will be spikes in gas prices,” says Molinaro. “Overall, your condo fees will be lower, your carbon footprint will be lower.”
Condo fees are reduced with the buildings’ significant drop in energy costs. Other expenses also fall with sustainable features such as solar lighting in outdoor parking lots and driveways and dual-flush toilets that reduce water use.
At TreeTops at Hidden Valley in Huntsville, natural gas was not an option and the developers felt geoexchange was a better choice than electricity or propane, says Club Leisure partner Lesley Gregory. TreeTops also has a contract with Ameresco to install and manage the system.
“We felt that we should be looking to the future and one of the things was to think of the energy efficiency of the buildings,” says Gregory.
De Sylva, an engineer, says it’s possible to include geo-exchange systems at no greater cost than more conventional systems.
“We have never priced our units more than the market average and they are often priced below,” says de Sylva. “If it’s not attainable, it’s not sustainable.
“We are efficient in what we do and we are multi-disciplined. We are a building company that builds residential and commercial buildings, a property management company, we design and service our own buildings and have our own trades.”
He says Del Ridge’s GreenLife buildings are designed to complement and get the most from the geoexchange technology. By building with Insulated Concrete Forms (ICFs), heavily insulating walls and roofs and using triple-glazed windows, the condo suites’ energy use is low. The buildings incorporate photovoltaic panels on the roof to collect solar energy and any additional electricity is purchased from green energy supplier Bullfrog Power.
De Sylva estimates the GreenLife buildings have about 15 per cent of the energy demand of a typically constructed building and the condo fees are a fraction of other condos (about 14 cents per square foot).
“We do a lot of data monitoring and we’ve had residents say their furnace hardly ever comes on. The average consumption is $12 a month for heating and cooling,” says de Sylva.
But geo-exchange is not a one-sizefits-all solution. De Sylva says a typical glass-and-concrete point highrise tower with a poor R value is not going to be a good candidate for geoexchange; as well, such a building would require a large bank of soil to accommodate the many deeply bored holes.
Geo-exchange is not yet a major energy contender in detached homes — except for green-minded homeowners who build custom homes — with its approximately $20,000-plus cost per house. As well, the payback is too lengthy, even in areas where natural gas isn’t available, says John Godden, a green building consultant and founder of the Sustainable Housing Foundation.
Craig Marshall, president of Marshall Homes, offered geo-exchange as an option at Copperfield, a lowrise site in Oshawa, but discontinued it. More efficient furnaces and the low cost of natural gas do not make it feasible yet for single family homes, he says.