Is ground source heating right for your home?
Ground source heating suits homes that are well insulated, have a low-temperature way to spread heat and have room for a loop. Where those conditions are met, it can supply most of a house's heat at low running cost, and where they are not, the design needs extra work or a different system.
Which homes suit ground source heating best?
New builds are the easiest case, because the loop, the floor heating and the insulation can be planned together. Among existing homes, the best matches are those that have been air sealed and insulated, with a heating system the heat pump can use. Houses that now burn oil or propane or use electric resistance have the most to gain, since those fuels cost a lot per unit of heat. Homes on low-cost natural gas see a longer payback, which the worth-it guide explains.
The load decides the size of the loop. Cutting heat loss before the system is designed means a smaller, cheaper loop, so insulation work comes first, as the insulation upgrade priorities show.
How does the way you spread heat matter?
A ground source heat pump works best when it delivers heat at a lower temperature. Floor heating and large low-temperature radiators let the unit run at a better efficiency than a high-temperature baseboard system, because the pump lifts the heat less. Forced-air systems work too, but the ducts must be sized for the airflow the heat pump needs, and leaky or undersized ducts reduce the benefit.
This is the same principle that made the Drake Landing district loop work. Its water ran at roughly 40 to 50 degrees Celsius, which low-temperature air handlers in the houses could use, as described on the air handler page. The theory is in low-temperature hydronic heating, and floor systems are covered in radiant floor heating.
What does the lot need to offer?
A vertical loop needs a spot for a drill rig and a few small boreholes, which suits narrow lots. A horizontal loop needs a larger open area for trenches, and a pond loop needs a suitable water body. Utilities, septic fields, buried services and trees all constrain the layout, so a site survey is part of the design. If drilling is not possible, an open-loop system may be, subject to water rules. Loop types are compared in horizontal and vertical ground loops.
The ground itself matters. Rock, clay, sand and groundwater conduct heat differently, which changes the amount of pipe needed. A thermal response test on a trial borehole can measure this for larger projects.
What are the limits of ground source heating?
Installation cost is the main limit. The loop is a heavy upfront investment, and on small or hard-to-reach sites it may not pay back within a reasonable time. Heating-dominated climates also load the ground heavily, which has to be accounted for in the design, because taking more heat than flows back can cool the ground year after year. The guide to borehole depth and spacing explains how designers handle this.
Not every contractor is equipped to do the work, and short supply of drillers can add delay in some regions. Cost drivers are listed in geothermal heat pump cost in Canada.
What should you do before you ask for quotes?
Know your house. A recent energy audit gives the heat loss and points to the cheapest improvements, and the steps are described in home energy audit in Canada. Check your yard for access and buried services. Decide whether you would add floor heating or use the existing ducts. Then ask each bidder for the load calculation, the loop design and the expected energy use in writing, so the offers can be compared on the same basis. The guide to geothermal rebates and financing says where to confirm current programs.
Quick answers
Can I use ground source heating with radiators?
Yes, if the radiators are large enough to heat the house with lower water temperatures. Small old radiators may need to be replaced or supplemented.
Does ground source heating work for older homes?
Often, after air sealing and insulation. Ducts or distribution may need work, and the loop size depends on the improved heat loss.
How much land does ground source heating need?
A vertical loop needs little surface area, while a horizontal loop needs a large open area. The design and the soil decide the actual need.
Does the ground get colder after years of heating?
A well-designed loop is sized so the ground recovers over the year. Poorly sized loops can slowly cool the ground, which is why the design matters.