What is a Ground Source Heat Pump?
A ground source heat pump (GSHP) extracts heat from the ground to heat your home. It uses a network of underground pipes (a ground loop) filled with fluid that absorbs heat from the soil. This low-grade heat is then compressed, raising its temperature, and transferred into your home via radiators, underfloor heating, or hot water systems.
The ground stays at a fairly constant temperature all year round (around 10°C in the UK), which means GSHPs can operate very efficiently, even in winter.
How does a GSHP work?
The process is similar to an air source heat pump, just with a different heat source:
- Heat collection – Fluid in underground loops absorbs heat from the soil.
- Compression – A compressor increases the temperature of the collected heat.
- Heat exchange – The now-hot fluid transfers its heat into your home’s system.
- Cycle continues – The cooled fluid returns to the ground to collect more heat.
There are two main types:
- Horizontal loops – require a large area of land for trenching.
- Vertical boreholes – require deep drilling, often 50m+ per borehole.
So why don’t we install many in the UK?
At Heat Geek, we focus on system design, efficiency, and real-world outcomes. And while GSHPs can be excellent in the right conditions, we rarely recommend them. Here’s why:
1. Cost
Ground source systems are expensive. Drilling boreholes or digging large trenches adds thousands to the upfront cost. That spend often doesn’t deliver better performance than a well-designed air source heat pump (ASHP).
2. Space requirements
You need either a large garden (for horizontal loops) or space for drilling rigs (for vertical boreholes). Most UK homes simply don’t have the land or access.
3. Complexity
Install logistics are harder, riskier, and more time-consuming. Ground conditions vary. Planning is more involved. Fixing issues later is harder.
4. Comparable performance
Modern air source heat pumps are now extremely efficient, especially when designed properly. The real-world performance gap between GSHP and ASHP is small when systems are well-specified.
5. Lower disruption and faster installs with ASHPs
An air source heat pump can be fitted externally with minimal disruption in days, not weeks.
Why we install Air Source Heat Pumps instead
For most homes in the UK, air source heat pumps are:
- More cost-effective
- Easier to install
- Space-efficient
- Supported by the Boiler Upgrade Scheme (BUS)
And when designed properly – which is what we do best – they can deliver seasonal efficiencies on par with ground source systems.
When would a GSHP make sense?
We’re not anti-GSHP. In fact, they can be a great choice if:
- You’re building from scratch
- You have significant outdoor space
- You want to hide the whole system underground
- You have the budget for the upfront cost
But for 99% of UK homeowners, an air source heat pump offers 95% of the benefits for much less money.
Want to find out what suits your home?
Every install starts with proper system design. Book a Design Consultation and we’ll spec the best system for your home.
FAQs
Are ground source heat pumps more efficient than air source?
Slightly, in theory. But in real-world UK homes, a well-designed ASHP can match or exceed GSHP performance.
Do ground source heat pumps work in winter?
Yes. The ground stays warm relative to the air, so performance remains stable year-round.
Is it worth paying more for a ground source heat pump?
In most cases, no. The extra cost and disruption outweigh the small efficiency gains.
How deep do boreholes need to be?
Typically 50–100 metres deep, depending on heat demand and ground conditions.
Do air source heat pumps work as well in cold weather?
Yes. Modern systems are designed for UK winters and work efficiently even below freezing.
