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Ground-Source Heat Pumps (GSHP)
Closed-loop borehole, open-loop groundwater, performance, installation.
11 min read · Jacob Willis, Net Zero Lead · Last reviewed July 2026
A few metres below the surface, UK ground holds a steady 8 to 12 °C all year: warmer than winter air exactly when heating demand peaks, cooler than summer air exactly when cooling demand peaks. A ground-source heat pump (GSHP) swaps the air-source machine's fickle outdoor coil for that stability, buying a consistently smaller temperature lift at the price of serious groundworks. This lesson covers how the ground loop works, what the stability is worth, and the honest economics of when the digging pays.
In this lesson
- 01The ground loop
- 02What the steadier source is worth
- 03Design realities
- 04Sources and further reading