What is a geothermal heat pump and who is it for?
A geothermal heat pump is an electric heating and cooling system that exchanges heat with the ground through a buried loop. It costs more to install than an air-source heat pump, and in return it offers steady performance in cold weather and lower running costs for houses that suit it.
What does a geothermal heat pump do through the year?
In winter the ground loop collects heat from the earth, and the heat pump raises it to a temperature suited to the house. In summer the process reverses and the system moves heat from the house into the ground, which gives cooling and dehumidifying from the same equipment. Many units add a heat exchanger that preheats domestic hot water with spare heat, so the geothermal heat pump serves all three jobs and cuts energy use in each.
Because the ground stays closer to a constant temperature than outdoor air, the unit runs under steadier conditions all year. An air-source heat pump, by contrast, has to work harder on the coldest and hottest days. The full cycle is explained in how ground-source heat pumps work.
What are the main advantages?
- Efficiency in cold weather. The geothermal heat pump output does not drop away with the air temperature, so the system needs less backup heat than many air-source models.
- Quiet and tidy outdoors. There is no outdoor fan and compressor unit, so noise and snow on equipment are not issues.
- Long loop life. The buried pipe is expected to last much longer than the equipment indoors, as the lifespan guide explains.
- Comfort. Steady heat delivery and built-in cooling and dehumidifying.
What are the drawbacks?
The first is price. Drilling or trenching for the loop dominates the cost, so the upfront figure for a geothermal heat pump is higher than for an air-source system, even though its energy efficiency is better, and the savings take years to repay it. The drivers are in geothermal heat pump cost in Canada. The second is site: vertical drilling needs a rig to reach the yard, and horizontal loops need generous land. Lots with rock, a high water table or tight access can raise the price further.
It is also a long project, with design, permits, drilling and commissioning, and not every contractor in every region installs these systems. Retrofits in homes with old ducts can need further work. The installation process guide lays out the sequence.
Who is a geothermal heat pump best for?
The best candidates plan to stay in the house for many years, build new or replace a system at the end of its life, and have a lot with room for the loop. A tight, well-insulated home keeps the load and the size of the loop down. People heating with propane, oil or electric resistance see the largest savings, since those fuels are expensive per unit of heat. Homes already on low-cost natural gas see slower paybacks, and the question of whether it is worth it is covered in are geothermal heat pumps worth it.
For a direct comparison with the cheaper option, read air source versus ground source heat pumps.
What does ownership look like after installation?
Day to day a geothermal heat pump needs little attention: change filters, keep the loop's pressure and fluid within the range the installer sets, and book a periodic service. The schedule is in geothermal heat pump maintenance. Rebates and financing for geothermal heat pump installation exist in some provinces and from some utilities, and the terms change, so check them before you sign, using the guide to geothermal rebates and financing.
Quick answers
What is the difference between a geothermal heat pump and an air-source heat pump?
A geothermal unit exchanges heat with the ground through a buried loop, while an air-source unit uses outdoor air. The ground is steadier, which helps in cold weather, but the loop adds cost.
Can a geothermal heat pump also cool my house?
Yes. In summer it reverses and moves heat from the house into the ground, which cools and dehumidifies the air.
Does a geothermal heat pump need a backup?
Many are sized to carry the full load, so backup is smaller or optional, though some owners keep a small backup for outages and repairs. A load calculation shows what your house needs.
How long does a geothermal heat pump last?
The indoor unit lasts about as long as other heat pumps, while the ground loop is expected to last for decades. Check your model's documentation and warranty.