It is important to appreciate that geothermal systems are ideally paired with other passive house strategies if net zero is the goal. Orienting the home to maximize solar gains, daylighting and views are an obvious first step. Super-insulating walls, using triple-pane glazing for South and West-facing windows, and passive ventilation strategies all go a long way toward energy independence. In most cases in North America, the geothermal system will be designed around heating loads, so when paired with a ducted system, the ability to condition air for cooling is a bonus byproduct.
“Climatically, geothermal systems work almost anywhere,” says Jenista. “The choice between one system manufacturer or another is largely dependent on the system the mechanical contractor is aligned with, what is available and what is most cost-effective.”

As for any drawbacks, Jenista shares that other than first costs being total costs, geothermal’s only shortcoming is in its ability to heat a large volume of domestic hot water.

“A geothermal heat pump cannot keep up with six people taking a hot shower at the same time, so in larger homes, we would either add in a larger water storage tank or use a dual system incorporating an electric booster to preheat the water to the desired temperature.”

Though geothermal systems have been available for at least 50 years, they have not been widely used in residential design primarily because of the exorbitant first costs. In commercial architecture, where a building is planned as a 50-year asset, the first cost is easier to reconcile against the building’s operational costs. With greater use, equipment costs have become more manageable, and today, geothermal systems are now readily available for residential-scale spaces.