Learn · Sustainable Energy
A few meters down, the earth stays the same temperature all year. That steadiness is the energy you tap.
Say geothermal and people picture volcanoes and steam. That kind exists, but it needs rare geology. The version almost anyone can use is quieter and stranger. It runs on the fact that the ground barely changes temperature.
Dig down a few meters and the soil sits at a steady mild temperature through summer heat and winter cold. That stable ground is a reservoir you can pull heat from in winter and push heat into in summer.
A ground source heat pump does not make heat. It moves heat between your home and the steady earth, which takes far less energy.
Moving Heat Beats Making Heat
Burning fuel makes heat from scratch. A heat pump just relocates heat that already exists. Because moving is cheaper than making, a good ground source system can deliver several units of heat for one unit of electricity.
- ▸In winter it pulls warmth from the ground into the house.
- ▸In summer it runs in reverse and dumps house heat into the ground.
- ▸One system covers both heating and cooling.
▶ Watch
How the steady temperature underground becomes heating and cooling you can build around.
The earth is the most reliable battery you already own. It never runs out, and it holds the same charge every season of the year.
The Loop in the Ground
The heart of the system is a loop of pipe buried in the soil. A fluid circulates through it, trading heat with the ground. The loop can lie in long shallow trenches if you have land, or drop into deep boreholes if you do not.
That buried loop is also why the cost lands where it does. The digging is the expensive part. The running is the cheap part.
High to Install, Low to Run
This is the trade that defines ground source energy. You pay more up front to put the loop in the ground, then enjoy years of low, steady bills. It rewards people who plan to stay put and who value a system that barely changes once it is in.
- ▸Best installed during new construction, when the digging is already happening.
- ▸Strongest in climates with both cold winters and hot summers, where it earns its keep twice.
- ▸The loop outlasts almost everything else in the building.
Steady Is the Selling Point
Solar and wind chase a moving source. Ground source energy leans on something that does not move at all. That steadiness is unglamorous, and it is exactly what makes it dependable.
The takeaways
- →The ground stays a steady mild temperature you can heat and cool with.
- →A heat pump moves heat instead of making it, so it uses little power.
- →High to install, low to run. Best when you are building or staying put.