The highest capital cost of anything we install, the longest life, and the largest single federal credit available on a building measure. It is the right answer less often than it is sold, and unbeatable when it is.
A ground loop gives a heat pump a source temperature that barely moves through the year. That stability is what produces efficiencies an air-source machine cannot reach in February, and it is why the technology suits buildings with long ownership horizons and steady load.
It also costs two to three times what an air-source system costs, because most of the money is in the ground rather than the equipment. On a building that will change hands in five years, or one with a short heating season and a small load, an air-source system is the better investment. We will say so.
The Canadian design and installation standard is CSA/ANSI/IGSHPA C448 Series:25 — the 2025 edition, which replaced the 2017 version and runs to roughly 250 pages. It is the basis for current IGSHPA training.
The 2025 edition added district energy systems, energy foundations and energy piles, a waste water energy transfer annex, PE-RT piping, and additional heat transfer fluids including glycerin-based and detoxified ethylene glycol.
"Do you design to CSA C448, and which edition?"
It is a standard most Ontario geothermal contractors will not claim and will not contest. An undersized loop field does not fail on day one. It fails in year seven, when the ground has not recovered between seasons and the capacity is no longer there — at which point the fix is another drilling programme.
| Loop | Needs | Where it fits |
|---|---|---|
| Vertical closed loop | Drilling rig access; boreholes typically 100–180 m | Constrained sites, commercial and institutional. The default. |
| Horizontal closed loop | Open land and excavation | Rural and low-rise sites with the acreage. Cheaper per ton where land exists. |
| Pond or lake loop | A suitable body of water and approvals | Rare, cheap when available, heavily permit-dependent. |
| Open loop | Adequate groundwater and a discharge route | Lowest capital, highest regulatory and water-chemistry risk. |
A commercial loop field is designed, not estimated. On projects above a threshold that depends on load, that includes a formal thermal conductivity test — a test bore, instrumented and run long enough to characterise how quickly the ground around it gives up and takes back heat.
It costs money before the project is approved. It costs considerably less than a loop field sized on an assumed conductivity that turns out to be wrong.
On a commercial system the Clean Technology Investment Tax Credit returns 30%, refundable, on the qualifying system — loop field included. On a project where most of the cost is in the ground, that is the largest single credit available on any building measure in Canada.
Residential ground source does not qualify for the federal credit. The Ontario residential position is set out on the incentives page, including the 30 November 2026 date.
The heat pump equipment has a service life comparable to other mechanical plant. The loop field, correctly installed, is generally expected to outlast it by decades, which is why the ownership horizon matters so much to the business case.
A vertical loop needs rig access rather than acreage, which is why it is the default on constrained commercial sites. A horizontal field needs real land and is cheaper per ton where that land exists.
Not on small residential systems. On commercial loop fields it is how you avoid sizing the most expensive part of the project on an assumption, and we recommend it on anything of scale.
Commercial and industrial systems, yes, including the loop field, where the claimant is a taxable Canadian corporation. Residential systems are excluded from the credit.
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