# Geothermal direct use and ground-source heat pumps

Earth heat used directly, or shallow ground heat moved by heat pumps.

Source page: https://www.materialinsights.org/energy/e_geo_direct/

Capture · Geothermal · No. 36

- Capture
- Output: Heat and cooling
 Capture · Geothermal · Foundation · Energy

A ground-source heat pump turns 1 kWh of electricity into about 4.3 kWh of warmth, drawing the rest from soil.

Chart: Illustration: Geothermal direct use and ground-source heat pumps

##### Where it comes from

Chart: Map of where it comes from

A few metres down, the ground stays at a steady 4.5-21 °C. Pipes in trenches or boreholes 30-120 m deep gather that heat, while deep wells tap hot water directly.

##### Three things to know

1. In a German field test, heat pumps cut CO2 emissions by 64% compared with gas heating in 2024.
2. Ground loops last 50 years or more, while the indoor heat pump units last up to about 24 years.
3. Ground-source systems cost several times more than air-source units, but the extra is typically repaid in 5-10 years.

##### The journey

1. 1 **Shallow ground**Steady 4.5-21 °C below the surface
2. 2 **Ground loop**Buried pipes carry water and antifreeze
3. 3 **Heat pump**Compressor lifts heat to useful temperature
4. 4 **Or hot wells**Deep water feeds heating networks directly
5. 5 **Buildings**Homes, greenhouses, fish farms and spas
 Covered in [Earth's energy flows: sun, wind, water, heat and lifeEnergy](https://www.materialinsights.org/learn/energy/earths-energy-flows/)

##### Go deeper pick a tab to open it in full

## Other sections

- [Overview](https://www.materialinsights.org/energy/e_geo_direct/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_geo_direct/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_geo_direct/efficiency/index.md)
- [Techniques](https://www.materialinsights.org/energy/e_geo_direct/techniques/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/e_geo_direct/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_geo_direct/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_geo_direct/links/index.md)