You’ve probably heard of geothermal, also known as ground-source heat pumps. This is one of the most practical, efficient, and increasingly popular home heating and cooling technologies available to Canadian homeowners today.
See If Geothermal Is Right for YouSo let’s find out what a ground source heat pump actually is, how it works step by step, what’s inside it, and how it compares to the systems most Ontario homeowners already have.
But what is geothermal, how does it work, how much does it cost, and does it make sense for your home?
A geothermal heat pump, also known as a ground-source heat pump (GSHP), is a system that heats and cools your home by exchanging heat with the ground instead of the outside air. It uses a ground loop of buried pipes through which a heat-transfer fluid circulates, absorbing heat in winter and releasing it in summer. Inside your home, the geothermal unit with a compressor, refrigerant, and heat exchanger moves heat and distributes it for year-round comfort. 
A geothermal heat pump does not create heat by burning fuel or using electric coils. What it does is move heat from the ground into your home, or from your home into the ground. This process uses a refrigerant cycle and a small amount of electricity.
All this makes geothermal heating so efficient. You are not paying to create heat from scratch, you are paying to move it.
As you already know, a ground source pump operates in two modes, namely heating and cooling. Here’s a simple look at how it works:
During winter, a geo heat pump pulls heat from the ground and moves it into your home. Here’s how the process works:
Stage #1
Ground loop absorbs heat from the earth
A mix of water and antifreeze circulates through the “ground loop” (a network of pipes buried in your yard). As it travels, it absorbs the earth’s warmth and carries it indoors.
Stage #2
The refrigerant evaporates
Inside your indoor unit, the warmed fluid passes close to a refrigerant. Because the refrigerant is cold, it instantly absorbs heat from the ground fluid, causing it to boil and turn into a gas.
Stage #3
The compressor raises the temperature
Next, a compressor squeezes that gas tightly. By doing so, the system raises its temperature significantly, creating the heat needed to warm your home.
Stage #4
Heat is released into your home
The hot gas now travels through a coil. Your home’s heating system blows indoor air past this hot coil, soaking up the warmth and distributing it through your vents (or radiant floors).
Stage #5
The expansion valve resets the cycle
After releasing its heat, the refrigerant turns back into a liquid. It passes through an expansion valve, which lowers its pressure and temperature, allowing it to absorb more heat when the cycle begins again.
In cooling mode, the system seamlessly reverses this process.
So instead of drawing warmth from the earth, it captures the excess heat from your indoor air and transfers it into the ground loop. Because the earth beneath the surface remains consistently cool compared to the scorching summer heat, it acts as a highly effective heat sink.
In this mode, the system effectively removes indoor heat, even during very hot summer days.
A geothermal heat pump system consists of several core components that work together to deliver efficient heating and cooling. 
Component | What It’s For | Did You Know? |
| Ground Loop (horizontal/vertical) | Transfers heat between the ground and the heat pump by circulating a water-antifreeze mixture | An improperly sized loop will ruin the system’s efficiency, so choose a certified installer. |
| Ground Source Heat Pump (indoor unit) | Extracts, concentrates, and moves heat between the ground loop and your home’s distribution system | This unit lasts much longer than ordinary ACs because it is housed safely indoors, away from harsh weather |
| Ductwork | Distributes heated or cooled air throughout the house through the ductwork system | Leaky ducts can waste up to 30% of your geothermal energy, so make sure yours are properly sealed |
| Communication Modules | Includes smart controls, thermostats, and zoning systems that manage system performance | Geo systems work best when keeping a steady temperature, so avoid drastic “temperature setbacks” at night |
| Accessories (flow center, pumps, valves) | Keeps the loop fluid moving through the system and helps maintain proper flow and pressure. | Opt for variable-speed circulation pumps. They automatically adjust fluid flow, using less electricity |
| Desuperheater | Recovers excess heat from the geothermal system to heat domestic hot water | This unit gives you virtually free hot water all summer long by recycling the heat pulled out of your house |
| Storage System (buffer tank/desuperheater tank) | Stores heated water, improves system performance, and can provide a reserve supply of hot water | A buffer tank prevents “short-cycling”, which protects the compressor |
Ground source heat pump (GSHP) systems are typically classified in two ways: by how they deliver heating and cooling inside the home, and by how they exchange heat with the ground.These categories work independently of each other. For example, you can have a closed-loop system that uses water-to-air or an open-loop system that uses water-to-water. To better understand the available options, geothermal heat pump heating systems can be broken down into two main categories: 
| Type | How It Works | Best Suited For |
| Water-to-air | Transfers heat from the ground loop into forced air, distributed through ductwork | Homes with existing forced-air ductwork |
| Water-to-water | Transfers heat from the ground loop into heated water for radiant floors or hydronic systems | New builds, homes with radiant floor heating |
| System Type | Best Suited For | Did You Know? |
| Horizontal Closed Loop | Large yards or rural properties with plenty of open acreage. | IT requires long shallow trenches and is the most affordable to install, but it temporarily disrupts your yard. |
| Vertical Closed Loop | Suburban homes, tight lots, established landscaping | These pipes go straight down into boreholes up to 400 feet deep. They use 80% less yard space than horizontal loops, saving your lawn and trees |
| Pond/Lake Closed Loop | Waterfront homes with a deep, permanent body of water nearby | Water transfers heat faster than soil, so submerging the pipes eliminates the need for costly digging entirely |
| Open Loop | Properties that already have a high-volume, reliable water well. | This system draws in groundwater, removes its heat, and returns it clean. It offers the highest efficiency possible but requires a steady water supply |
Whichever system combination you choose, it will benefit you for decades by turning the ground beneath your feet into a clean, highly efficient energy source.
When evaluating a geothermal heat pump, you will constantly run into two metrics: COP (Coefficient of Performance) and EER (Energy Efficiency Ratio).Here is the simple breakdown of what they mean and how to read them. 
COP measures the system’s efficiency while it is in heating mode. It is a simple ratio of energy delivered versus energy consumed.
EER measures the system’s efficiency in cooling mode (acting as a central air conditioner).
While both technologies move heat rather than generating it, the key difference lies in where they get their energy. In Canada’s cold winters, this choice greatly affects how well your system works when you need it most. 
| Feature | Ground Source (Geothermal) | Air-Source Heat Pump |
| Where it gets heat | The earth (always a mild 7–10°C underground) | The outdoor air (changes with the weather) |
| When it hits -20°C | Consistent performance. Deep ground temperatures remain stable regardless of weather | Reduced capacity. The system must work harder and use more electricity |
| Heating COP | 3.0 to 5.0 (delivers up to 500% efficiency) | 1.5 to 2.5 (drops significantly in deep cold) |
| Cooling efficiency | Very high (ground acts as heat sink) | Moderate (air temp rises in summer) |
| Upfront cost | Higher ($25,000 – $45,000+) | Lower ($8,000 – $18,000) |
| Installation | Complex. Requires backyard digging or drilling | Simple. Just an outdoor unit bolted outside your wall |
| How long it lasts | 20–25 years for the indoor unit and 50+ years for the loop | 15–20 years max (it sits out in harsh weather) |
| Maintenance | Very Low. Everything important is safely indoors. | Low to Moderate. Needs clearing from snow and ice. |
Note: An air-source heat pump is cheaper to install and is a good option for moderate climates. However, in Ontario and most of Canada, where you need heat the most when it’s cold outside, a ground source heat pump is more efficient.
While both systems are designed to keep your home warm, the key difference lies in how they create that warmth.
| Feature | Ground Source (Geothermal) | Natural Gas Furnace |
| How it heats | Moves existing heat from the ground indoors | Burns natural gas to create new heat |
| Heating efficiency | COP 3.0 to 5.0 (300% to 500% efficient) | AFUE 80% to 98% (maximum 98% efficient) |
| Cooling capability | Yes. Full central air conditioning is built right in | No. Requires a completely separate central AC unit |
| On-site emissions | Zero. Clean operation with no combustion | Produces CO₂ and NOₓ from combustion |
| Monthly running cost | Lower. Minimizes monthly bills by using only electricity. | Moderate. Subject to fluctuating gas prices and carbon taxes |
| Upfront cost | Higher ($25,000 – $45,000+) | Lower ($4,500 – $9,500 for the furnace unit alone) |
| Lifespan | 20–25 years for the indoor unit and 50+ years for the loop | 15–20 years before requiring replacement |
Note:A gas furnace costs less to install at first. However, a geothermal system can be up to 400% efficient because it moves heat instead of burning fuel. For homeowners in Ontario, this means annual heating and cooling bills can drop by 40% to 70%. The typical payback period for a geothermal system is 10 to 15 years.
Professional heat pump installation ensures efficient heating and cooling for your home, improving comfort and energy savings year-round.
