Energy & EPC

Ground Source Heat Pumps, How They Work and Whether They Suit Your Property

Ground source heat pumps extract heat from below ground and can deliver highly efficient home heating, but they require significant installation work and sufficient land. This guide covers how they function, their costs, and suitability criteria.

Published: 16 Mar 2026 · Updated: 16 Mar 2026 · 7 min read

#EPCRating#EnergyEfficiency#GroundSourceHeatPump#HeatPump#GreenEnergy#PropertyPassportUK

How Ground Source Heat Pumps Work

A ground source heat pump (GSHP) transfers heat from the ground into your home. The ground at a depth of around one to two metres or more maintains a relatively stable temperature year-round, typically between 8°C and 12°C in the UK, regardless of air temperature above.

The system works by circulating a water-antifreeze mixture through a network of pipes (the ground loop) buried in the earth. The mixture absorbs heat from the ground and carries it to a heat pump unit inside the building. The heat pump then uses a refrigerant cycle, similar in principle to a refrigerator operating in reverse, to concentrate that heat to a useful temperature for space heating and hot water.

Because the system moves heat rather than generating it through combustion, a GSHP can deliver significantly more energy in heat than it consumes in electricity, a ratio expressed as the Coefficient of Performance (CoP). Typically, a well-installed GSHP in a suitable home achieves a seasonal CoP of 3 to 4, meaning three to four units of heat for every unit of electricity consumed.

Ground Loop Options

Type	How it works	Land requirement
Horizontal loop	Pipes buried 1–2 m deep in trenches	Large, typically 2–3× the floor area of the property
Vertical borehole	Pipes inserted into boreholes 50–150 m deep	Minimal footprint, suits smaller plots
Ground array (slinky)	Coiled pipes in shallower, wider trenches	Moderate, between horizontal and vertical

Horizontal loops are the most common in rural properties with large gardens. Vertical boreholes cost more to drill but require far less land, making them viable for suburban properties.

Comparing Ground Source and Air Source Heat Pumps

Factor	Ground source	Air source
Seasonal efficiency (CoP)	Typically higher (3–4+)	Typically 2.5–3.5
Installation cost	Higher (groundwork required)	Lower
Land requirement	Significant (or borehole)	Minimal
External noise	None (unit is internal)	Fan unit audible outdoors
BUS grant	£7,500	£7,500
Planning permission	Rarely required	Rarely required

Is Your Property Suitable?

Ground source heat pumps are most effective in properties that are:

Well insulated, with low heat loss
Fitted with underfloor heating or large radiators capable of operating at lower flow temperatures (typically 35–45°C, compared to 70–80°C for a conventional gas boiler)
Not reliant on a district heat network or communal system
Located on a plot with sufficient outdoor space for a horizontal loop, or able to accommodate borehole drilling

Properties with poor insulation can still use a GSHP, but the efficiency will be lower and the running costs higher. Before installation, a heat loss calculation should be carried out by the MCS-certified installer to correctly size the system.

Cost

Ground source heat pump installation in the UK typically costs considerably more than air source, due to groundwork. A horizontal loop system in a medium-sized house commonly runs to a total installed cost of £15,000 to £30,000 before grant. A vertical borehole system can be higher still. After the £7,500 Boiler Upgrade Scheme grant, the net cost remains substantial.

Running costs depend heavily on your electricity tariff. Economy 7 and heat pump-specific tariffs offered by some suppliers can reduce the cost of operation.

The Boiler Upgrade Scheme

Ground source heat pumps are eligible for the same £7,500 BUS grant as air source heat pumps. The same eligibility rules apply, your property must have no outstanding EPC recommendations for loft or cavity wall insulation, and installation must be carried out by an MCS-certified contractor. See Property Passport UK to check your current EPC status and recommendations before applying.

Planning and Permitted Development

Installing a ground source heat pump is considered permitted development in most circumstances in England and Wales, meaning planning permission is not normally required. However, in listed buildings, conservation areas, or Areas of Outstanding Natural Beauty (AONBs), restrictions may apply. Always confirm with your local planning authority before groundworks begin.