What is geothermal energy?
Geothermal energy is heat that is naturally present in the earth’s subsurface. This heat is generated by the decay of radioactive elements in the earth’s core and mantle. The deeper you go, the warmer it gets — on average, the temperature rises by about 3 °C per 100 metres of depth.
How does geothermal energy work in construction?
In the construction sector, geothermal energy is used as a sustainable energy source for heating and cooling buildings. There are two main types:
- Shallow geothermal energy (up to approx. 500 m) — a ground heat exchanger (borehole or horizontal collector) is installed. A heat pump extracts low-temperature heat from the ground and raises it to a usable temperature for underfloor heating or radiators
- Deep geothermal energy (from 500 m to several kilometres) — hot water is pumped up from deep rock layers. This water has a temperature of 60 °C to over 100 °C and can be used directly for heating or a district heating network
Application
Geothermal energy is increasingly used in new construction and energy retrofits:
- New-build homes — a ground-source heat pump with vertical boreholes is a popular choice for gas-free homes
- Commercial buildings — offices and schools use ground-coupled heating and cooling systems
- District heating networks — deep geothermal sources supply entire residential areas via a collective heat network
Advantages
- Sustainable — geothermal energy is virtually inexhaustible and low in CO₂
- Constant source — the ground temperature is stable regardless of the season
- Low energy consumption — a heat pump delivers 3 to 5 times more energy than it consumes
- Dual use — in summer the system can also provide cooling
Related terms
- Heat pump
- Insulation
- Sustainable building
- Foundation
- Underfloor heating
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.