Ground Source Heat Pumps: Are They Worth It?

What Is a Ground Source Heat Pump?

A ground source heat pump (GSHP) extracts heat from the ground — which remains at a relatively stable 8–12°C year-round in the UK — and uses a refrigerant cycle to deliver that heat to your home at a useful temperature.

Unlike air source heat pumps, which extract heat from outside air (which varies with the weather), ground temperatures are stable. This gives GSHPs a more consistent and typically higher efficiency throughout the year.

How Ground Source Systems Work

Heat is collected from the ground via one of two methods:

Horizontal Ground Loops

Pipes are laid in trenches approximately 1–1.5 metres deep across a large area of your garden. A typical 3-bedroom home requires around 400–600 metres of pipe, needing a garden area of at least 200–300 square metres.

Vertical Boreholes

Where garden space is limited, boreholes are drilled to a depth of 50–150 metres. More expensive to drill but requires far less surface area.

Performance and Efficiency

GSHPs typically achieve a COP (Coefficient of Performance) of 3.5–5 — meaning 3.5 to 5 units of heat for every unit of electricity. This is generally higher than air source heat pumps, particularly in cold weather.

Annual SPF (Seasonal Performance Factor) of 3–4 is typical for a well-designed ground source system.

Costs

| Item | Typical Cost |

|------|-------------|

| Heat pump unit | £8,000–£15,000 |

| Horizontal ground loop installation | £5,000–£10,000 |

| Vertical borehole(s) | £10,000–£20,000 |

| Internal pipework, cylinder, electrical | £3,000–£6,000 |

| **Total (horizontal)** | **£18,000–£30,000** |

| **Less BUS grant** | **-£7,500** |

Is a GSHP Worth It?

Advantages over air source:

Higher, more consistent efficiency

Quieter operation (no outdoor unit fan)

Longer lifespan (25–50 years for the ground loops)

Performance doesn't degrade in cold snaps

Disadvantages:

Much higher installation cost

Requires significant garden space (or expensive boreholes)

Disruptive installation process

Our verdict: GSHPs are worth considering for larger rural properties with available land, where the higher COP justifies the additional installation cost over the long term. For most suburban homes, an air source heat pump offers a better cost-benefit ratio.

Call Halo Heating on 01483 676108 to discuss which heat pump type is right for your property.