Rising natural gas bills and global warming concerns are driving more homeowners “underground” – to an environmentally friendly energy source.

Geothermal energy, the Earth’s natural energy source, has been used for years to heat and cool large commercial buildings in Alberta.

But now a growing number of homeowners are choosing geothermal technology over a conventional, gas-fired furnace or electric heating.

Increasing demand for residential geothermal systems is being spurred mainly by escalating natural gas costs. But some homeowners also want to do their part to reduce greenhouse gas emissions produced by burning fossil fuels.

“We chose the (geothermal) system because we wanted to do something for the environment,” says Calgary-area resident Carol Haika.

Larry MacDougal, Business Edge
Carol Haika was looking for an environmentally friendly temperature-control system.

She and husband Frank and their family had a geothermal system installed in their home in the Elbow Valley community just west of the city.

Geothermal is “a bit more expensive up front” compared with a regular gas-fired furnace, Haika says. “But when we did our research, looking at other installations, it appears that the payback period was about three years.”

Don Parsons, systems designer at Earth Geothermal Inc. in Red Deer, says studies by Natural Resources Canada’s Office of Energy Efficiency and other independent organizations show the payback period on a geothermal system for an average-sized home is about four to six years for a “properly designed and installed system.”

With homes that are larger than average, cost efficiencies shorten the payback time. And as gas prices go up, geothermal becomes more attractive.

“We’ve seen a growth in demand in the past four years of probably about 100 per cent per year,” Parsons says. “It really has picked up this year,” agrees Denton Hocking, residential representative for Calgary-based Histech Energy Solutions Inc.

Rick Richards of Alberta Geothermal Inc. in Calgary says homeowners are feeling anxious about unpredictable natural gas prices and the future of fossil fuels.

“People are just starting to think, ‘We’ve got to do something to have efficient heating for our homes, as well as do something for the environment.’ ”

Natural gas, although a relatively clean-burning fossil fuel, still emits carbon dioxide – the main greenhouse gas blamed for global warming.

Geothermal, on the other hand, is virtually emission-free. The Haikas’ home system keeps an estimated 12 tonnes a year of CO2 out of the atmosphere.

Geothermal technology for homes and commercial buildings has been widely used in Europe for more than 50 years, and in the United States and Eastern Canada for more than two decades.

The technology is based on “taking advantage of the constant temperature in the Earth,” says Histech Energy’s Hocking.

Three or more metres deep in the ground, below the frost line, the temperature year-round is a fairly constant 7° C. Geothermal technology taps into this subterranean climate.

First, a closed network of polyethylene pipes is laid in trenches below the frost line, or the pipes are installed vertically in small holes drilled to depths of 70 metres or more.

An antifreeze liquid is then pumped through the pipes, looping down into the ground and running back into the geothermal unit in the home.

“In the wintertime, (the liquid) comes back warmer than what the temperature is outside,” Hocking says. “In the summertime, it comes back cooler.”

The liquid is passed through a heat exchanger and compressor to maximize heat production, either in the form of forced hot air or in a heated solution circulated through tubes embedded in concrete floor slabs.

The entire system works in reverse in the summer as an air-conditioner, moving heat from the house into the ground.

Haika says geothermal efficiently heats or cools her family’s spacious home, which is about 8,000 sq. ft. including a fully developed attic and basement.

Industry experts say the cost of a geothermal system for an average-sized home is about $15,000 to $20,000, depending on the sophistication of the components. That’s about 1.5 to two times the cost of installing a conventional gas-fired furnace and air conditioning unit for the entire house.

Once a geothermal system has been installed, however, monthly energy costs are typically about half those for a conventional heating-air conditioning system, says Alberta Geothermal’s Richards.

The geothermal system’s heat exchanger, compressor and other electrical components do add to the household electricity bill. But this extra cost isn’t substantial, industry experts say.

Although demand for residential geothermal systems is heating up in Alberta, the province lags British Columbia, Manitoba, Ontario and the Maritimes in adopting the technology. That’s because until recently, natural gas has been comparatively cheap for Alberta consumers.

Parsons also points out that in other places, the provincial government or local utility company offer financial subsidies for residential geothermal systems, to help offset the initial up-front investment.

Earth Geothermal has been lobbying the Alberta government – so far without success – to offer a similar incentive, Parsons says.

Richards says one of the biggest obstacles to expanding geothermal technology here is the attitude that the province has a limitless supply of natural gas.

“We might,” he acknowledges. “But are we willing to pay for it?’” Despite the lack of government support, geothermal is catching on.

Parsons says he’s working on a design for a corporation’s proposed 400-unit condominium complex in Southern Alberta that would be heated and cooled entirely with geothermal energy.

Home developer United Com- munities is installing geothermal systems in five of its showhomes, to open early this summer in the New Discovery community in Elbow Valley.

If prospective homebuyers like the technology, it could be used in all of the developer’s new projects, says a spokesman for United Communities.

Richards points out that even U.S. President George W. Bush, despite his opposition to the Kyoto Accord, relies on a geothermal system in his ranch house in Texas. “So if George can do it, we can do it.”

Web watch: www.earthgeothermal.com/ www.albertageothermal.ca/