With special rebates available and the promise of long-term savings, green technologies like geothermal heating and cooling are piquing the interest of homeowners.

But can geothermal be installed in the city? Can you retrofit a home to run a geothermal system? And what the heck is geothermal heating and cooling anyway?

«The common misconception is that we need to drill down into the earth into somewhere where it’s warm and we bring that warm liquid or air or whatever it is up and we circulate that through the house, which absolutely isn’t true,» says Kevin Bergeron, co-owner and president of Dwight’s Next Energy.

«We’re actually creating heat through a refrigeration cycle based on the energy we’re grabbing from the earth.»

How Does Geothermal Work?

Under the frost line, the earth stays a relatively consistent temperature all year long, and geothermal systems take advantage of that.

In the winter, the system sends out a cold, engineered fluid through a closed loop system under the frost line. As it travels through the pipes, it warms up.

The warmed up fluid is still cold to the touch, like cool tap water, but it contains more energy than when it was sent out, and that extra energy is what’s important to the geothermal technology. The fluid then exchanges its energy with a refrigerant that boils at a very low temperature.

«We take that refrigerant and we run it through a compressor, just like the compressor on the back of your fridge, or a regular air conditioner,» explains Bergeron.

Because compressed refrigerant creates heat, they’re able to get temperatures up to about 43 to 65 degrees Celsius from the refrigerant.

«We take that hot refrigerant, and we now will circulate it through an air coil and then blow air across that air coil, just like a regular furnace blows air across an air coil that’s heated by natural gas or electric.»

During the summer, the system essentially reverses, pulling heat from the air in the house to warm the liquid, then depositing the heat in the ground outside, and bringing the liquid back at a lower temperature.

Pros and Cons

In the past 13 years, Dwight’s Next Energy has installed about 1,200 geothermal systems in the province. About 99 per cent of those were in rural areas because geothermal is cheaper than the alternatives of either propane or diesel, or getting a natural gas line out to the home. For rural homeowners, the capital costs can be recovered in four to five years.

In the city, though, it costs next to nothing to connect a home to a natural gas line, while a geothermal system will cost around $10,000. (This figure is the average cost a geothermal system would cost compared to a natural gas system). And because natural gas is so cheap, Bergeron estimates you might only save $500 per year with a geothermal system compared to a high-efficiency furnace and air conditioner. At that rate, it could take 15 to 20 years to recoup the upfront costs.

Retrofitting a home is possible, but Dwight’s needs to be able to get access to the backyard to do the drilling, through a back alley, for example. New builds are easier because they can install the loops before the foundation is dug.

But there are still benefits for city slickers: the system is quiet, there’s no air conditioner eyesore in the yard, your natural gas bill will disappear completely, and there’s zero risk of carbon monoxide poisoning because no natural gas is hooked up to the house.

The temperature in the house also remains more steady because geothermal systems run longer and circulate more air at a lower temperature compared to most furnaces that blast a house with hot air then turn off until the temperature dips again. The increased circulation also keeps humidity in check, and can help with allergies.

A Homebuilder’s Perspective

Cam Skoropat, co-owner of Lexis Homes, worked with Dwight’s to install a geothermal system in a new build in Evergreen recently, and he says the process was painless. technology were relatively minor: they needed an engineer to supply site drawings, the build started with drilling for the geothermal pipes instead of starting with the foundation, and trades needed to be informed that they’d be working with the technology.

Geothermal also didn’t affect the design of the house in any way, says Skoropat.The system fits neatly in the utility room just like a regular furnace. You would never know the house has geothermal heating and cooling unless you visited the utility room and noticed the equipment was different.

Since completing the Evergreen home, Skoropat says they ask all homeowners if they’re interested in geothermal heating and cooling.

Ashleigh Mattern

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