Beneath our feet

From rural schools and retirement villages to high-rise flats in bustling cities, closed loop ground source heat pump (GSHP) systems are quietly reshaping Britain’s energy landscape. Mike Moggeridge, Managing Director of Qvantum Solution Design, explains how this technology is unlocking the vast geothermal resources hidden beneath our towns, campuses and coalfields.

In an era defined by climate commitments, energy price volatility and a need for infrastructure that delivers quietly and efficiently, ground source heat is making a powerful resurgence. Once an underused niche, closed loop systems have emerged as a leading low-carbon heating and cooling solution for buildings across the public, residential and community sectors. At their core, these systems harness the Earth’s natural and stable subsurface temperatures by circulating a heat transfer fluid through a sealed underground pipework loop. This fluid absorbs heat in winter and dissipates it in summer in cooling mode — providing a renewable, low-carbon source of comfort that operates silently, safely and with minimal maintenance.

 

Where closed loop GSHPs deliver best

One of the greatest strengths of closed loop GSHP systems is their adaptability. With proper site investigation and ground modelling, they can be deployed across a wide variety of developments:

Schools and education campuses: With consistent, term-time heat demand and accessible outdoor space, schools are ideal candidates. GSHPs can be installed below playing fields or car parks, delivering reliable heat with lower running costs and emissions —a critical factor for councils and academy trusts managing tight budgets.

Retirement villages and care homes: In environments where quiet, consistent warmth is essential, GSHPs outperform combustion systems. They integrate well with underfloor heating, reduce indoor air pollution, and support Net Zero ambitions in the care sector.

High-density residential and urban flats: Vertical boreholes allow these systems to serve multi-storey blocks, even in space-constrained areas. Central plantrooms can feed multiple apartments via low-temperature distribution systems — decarbonising urban living with no rooftop space required.

Community and district-scale networks: With the right borehole array and thermal modelling, closed loop systems can anchor localised heat networks for clusters of buildings or even entire developments — making them ideal for regeneration zones, public sector estates and campus-style layouts.

 

Why closed loop?

Unlike open loop systems that extract and discharge groundwater, closed loop boreholes are entirely sealed. They exchange heat through direct contact with the surrounding geology — removing the need for Environment Agency abstraction licences, groundwater risk assessments, or f low-based performance dependency.

This makes them ideal for sites where:

• Water quality is poor or uncertain;
• Regulatory timelines are tight;
• Simplicity and predictability are critical;
• Infrastructure must be installed and left to operate with minimal intervention.

With design lives of up to 100 years for boreholes and 25–30 years for heat pump units, closed loop systems offer unparalleled long-term value. Once installed, the energy beneath the building is forever available, making them a form of ‘subsurface energy security’.

 

Geology as an energy asset

Thermal conductivity — the rate at which heat moves through the ground — is a key metric for GSHP performance. And in this respect, UK geology is a strategic advantage. Sherwood and Warwickshire Sandstones, widespread across England, consistently return thermal conductivities of up to 3.45 W/m·K in Thermal Response Testing (TRT), while volcanic tuff formations in the Midlands have demonstrated conductivity results of up to 5.91 W/m·K, placing them among the highest recorded in the UK. Meanwhile, beneath cities like London, ground temperatures at depth reach 16.15°C — greatly enhancing winter heating performance. Yet it is in the coal measures that perhaps the most potential lies. The UK’s coalfields represent more than legacy — they offer real opportunity. Beneath towns from Glasgow to Cardiff, Nottingham to Newcastle, lie vast reserves of subsurface heat stored in the carboniferous coal measures. And it is now understood that the geothermal energy contained within Britain’s coal-bearing strata exceeds all the energy ever extracted from them as coal.

 

Supporting energy security and grid resilience

Closed loop GSHPs don’t just cut emissions — they help to reshape energy economics. By relying on local thermal resources rather than imported fuels, they improve the UK's energy independence, reduce exposure to price volatility, and shift heating loads away from peak electricity demand. They are uniquely well-placed to support electrification of heat strategies alongside:

• Smart controls and demand-side response
• Low-temperature heat networks
• Grid-stabilising infrastructure in all-electric buildings

As fossil fuel heating systems are phased out, these systems form a quiet but crucial backbone of the UK’s clean energy transition.

 

Financing the future

To support the deployment of GSHPs at scale, public and private sector access to capital is essential. Fortunately, two major government funds are actively enabling this:

Green Heat Network Fund (GHNF)1: The GHNF provides capital support for new and expanded low-carbon heat networks that use renewable sources—including GSHPs. Projects that incorporate closed loop borehole systems as the heat source, particularly within public or multi-building developments, are eligible for substantial grant support under this scheme. This fund is ideal for:

• Council-led district energy systems
• NHS estates or higher education campuses
• Regeneration zones with centralised plant

Warm Homes: Social Housing Decarbonisation Fund (SHDF)2: The SHDF supports upgrades to low-income and social housing stock to improve energy efficiency and reduce fuel poverty. Closed loop GSHPs, particularly when replacing gas boilers in apartment blocks or off-gas communities, can be part of a broader retrofit package funded under SHDF Wave 2. Registered providers and housing associations can apply individually or in consortia to secure funding that includes GSHP installations as part of a fabric-first, whole-home approach. With the right feasibility studies and stakeholder coordination, these funds can unlock entire portfolios of sites — ensuring low-carbon warmth for the households who need it most.

 

Conclusion: Beneath our feet lies the future

Closed loop borehole GSHP systems are a vital part of the UK's decarbonisation and energy security toolkit. Quiet, powerful, and engineered for the long-term, they offer a renewable heating and cooling solution ready to scale — across city centres, suburbs, rural towns and former coalfield communities. With the right funding, the right geological intelligence, and the right delivery partners, we can embed this technology across Britain’s infrastructure — turning dormant geology into a strategic asset. The transition is already underway. The question now is not if we drill, but where next.

 

www.qvantum.com/uk/about-solution-design

 

Source

1. www.gov.uk/government/publications/green-heat-network-fund-ghnf

2. www.gov.uk/government/publications/social-housing-decarbonisation-fund-wave-22