Ground-Source Heat Pumps (Commercial): Heat pumps for businesses

Why ground-source earns its place for year-round commercial buildings

Where a business runs its building all year and wants the highest, most stable efficiency money can buy, a ground-source heat pump is the strongest long-term answer. Instead of drawing heat from the outside air, it draws it from the stable temperature of the ground through a borehole array or horizontal ground loops, and because the ground stays at a steady temperature whatever the weather, the system holds its performance even in the coldest snaps when an air-source unit would dip. For commercial buildings with constant occupancy and a serious heat demand, that consistency is exactly what makes the case, and it is why ground-source remains the premium choice for the right kind of business rather than the default one.

Ground-source heat pumps for businesses suit organisations that intend to stay in their building for the long haul and need both heating and, often, cooling. The same plant can deliver low-cost passive or active cooling in summer by reversing the flow, which is valuable for offices, care homes, hospitals, hotels and leisure centres, and for spaces carrying IT or process heat. One plant set covering both seasonal duties improves the whole-life business case considerably. The capital is higher and the lead time longer because of the ground works, so this is a deliberate, modelled decision rather than a quick swap, and it earns its premium where the building runs year-round or where public-sector or heat-network funding can meet the capital.

The reason ground-source can hold an SCOP often above 4.0 all year comes down to physics. An air-source unit's efficiency dips when the outside air is coldest, which is unfortunately the exact moment a building needs the most heat. The ground a few metres down stays at a stable temperature regardless of the weather, so a ground-source system performs just as well in a January cold snap as in mild autumn weather. For a year-round building, that stability is worth real money, because the worst-case days are no longer the days the system struggles. It also removes on-site combustion entirely, so the only emissions are from grid electricity, which keeps falling as the grid decarbonises. That makes ground-source a particularly clean line in a net-zero report and a strong piece of Scope 1 and Scope 2 evidence for a business that has committed to a target and needs to show progress against it.

What a typical install looks like and how we size it

A commercial ground-source system usually falls in the 50 to 1,000 kW thermal range, served by a borehole array (typically 100 to 200m deep) or horizontal ground loops, with the ground or borehole field varying hugely in footprint from site to site. A system on that scale delivers in the region of 120,000 to 2,500,000 kWh of heat a year and removes between 22 and 450 tonnes of CO2 annually. As with all heat-pump work, we size from the building's peak heat-loss and annual demand profile rather than floor area, running a heat-loss survey and reviewing at least twelve months of gas or oil consumption. For ground-source we also recommend a ground investigation and thermal response test before final design, so the array is matched to the actual ground conditions rather than an assumption. Designed well, ground-source delivers an SCOP often above 4.0 year-round, and we hold the flow temperature as low as the emitters allow to keep that efficiency high, specifying to BS EN 14825 and BS EN 14511 so the figures are comparable.

Costs, payback and tax relief

Ground-source carries the highest capital of the standard commercial options, typically £150,000 to £2,000,000 and beyond, because of the drilling and ground works, with a simple payback in the region of 11 years on a self-funded basis. It earns that premium through the highest and most stable efficiency available, plus the bonus of low-cost summer cooling, so the whole-life cost on a year-round building is often very competitive once you model it properly. As with any heat-pump project for a business, the capital qualifies as plant and machinery, so a company can claim full expensing at 100% with no cap (permanent from April 2026, worth up to 25p of tax saved per pound at the 25% corporation-tax rate), and an unincorporated business uses the Annual Investment Allowance up to £1m. The high capital is also exactly why ground-source so often pairs with grant funding, which can transform the payback. Our cost guide compares air-source and ground-source side by side, and you should confirm tax treatment with your accountant.

Funding routes in detail

Grant funding frequently decides whether a ground-source scheme makes sense, and for the right organisation it can meet the bulk of the capital. Public-sector bodies, including NHS trusts, schools, colleges, universities, local authorities and emergency services, should look to the Public Sector Decarbonisation Scheme run by Salix for DESNZ, which funds low-carbon heating over and above a like-for-like fossil replacement through competitive windows, and which routinely backs ground-source on year-round public buildings such as leisure centres and care settings. Where the ground-source plant sits inside a multi-building or campus scheme, the Green Heat Network Fund can contribute up to 50% of eligible commercialisation and construction costs, with awards regularly running to several million pounds. Any business can layer full expensing or the Annual Investment Allowance on top of the qualifying capital. The domestic Boiler Upgrade Scheme does not apply to commercial buildings, so we map the routes that genuinely do.

Compliance and sector considerations

Ground works bring their own compliance layer. Borehole drilling requires Environment Agency awareness, and while closed-loop systems do not need a permit (they follow EA closed-loop guidance), open-loop systems that abstract and discharge groundwater do require an abstraction and discharge permit. We recommend a ground investigation and thermal response test before final design, and we design to CIBSE TM51 ground-source guidance and MIS 3005 design principles. For systems up to 45 kWth, MCS certification or a recognised commercial equivalent is required for most grant routes, with MCS 025 competency for the installer. Above that we work to CIBSE and BSRIA standards. Large heat pumps add significant electrical load, so we confirm DNO supply capacity early because an upgrade can be the longest-lead item, and all refrigerant work is carried out by F-Gas certified engineers under the UK F-Gas Regulation. Ground-source borehole arrays may require planning depending on scale, which we confirm at feasibility. Because the ground works carry a longer lead time and higher capital than an air-source install, we sequence the project so the drilling, the ground investigation and the planning and Environment Agency confirmations happen in the right order, and we factor the full timeline into the business case rather than presenting an optimistic best case that ignores the realities of working below ground.

How we approach this kind of project

Ground-source is a commitment, so our job is to make the decision on evidence, not optimism. We model air-source and ground-source side by side from your own half-hourly meter data and twelve months of consumption, so you see the whole-life cost of each before choosing, and we size for self-consumption and a low flow temperature to protect the SCOP. We carry out the heat-loss survey, the ground investigation and the emitter survey up front, confirm the planning and Environment Agency position, and submit the G99 grid application early where a supply upgrade is needed. You receive a fixed-price proposal and an insurance-backed warranty, with performance quoted to BS EN 14825 so it stands up against any compliant supplier. We would rather lose a job to honest maths than win it on a number we cannot stand behind.

Because the boreholes are the part that worries finance directors most, it is worth being honest about them. Yes, the drilling adds capital and lead time, and that is exactly why we model air-source and ground-source against each other rather than steering you toward the higher-value job. Where ground-source earns its premium it earns it convincingly: the stable year-round SCOP, the low-cost summer cooling, and the long life of the array, where the borehole field itself can last decades and the heat pump is serviced on the usual annual or six-monthly cycle. For a building that runs all year, or where PSDS or GHNF funding can carry the capital, the whole-life cost frequently comes out ahead despite the higher sticker price. Where it does not, we will tell you so and recommend air-source or a hybrid design instead, because the right answer is the one your building and your numbers support.

The running-cost logic is the same as for any heat pump but more favourable, because the higher SCOP offsets more of the electricity-to-gas unit-price gap. Electricity currently costs roughly three to four times the unit price of gas, but an SCOP above 4.0 means each unit of electricity buys more than four units of heat, so a well-designed ground-source system with low flow temperatures is comfortably positioned against gas running cost and improves further as carbon levies on gas rise and the grid decarbonises. We model that from your actual consumption at current and forecast prices, share the full model, and design for 45 to 55C flow wherever the emitters allow, with selective upgrades rather than a wholesale strip-out, so you are not paying to re-emitter a building that does not need it.

An illustrative example

As an illustrative composite based on a typical year-round commercial scheme, a council-owned leisure centre with a swimming pool, sports hall and continuous hot-water and space-heating load on an end-of-life gas boiler secured Public Sector Decarbonisation Scheme funding and installed a 450 kW ground-source heat pump on a borehole array, providing heating in winter and free cooling support to the sports hall in summer. It delivered around 1,050,000 kWh of heat a year at an SCOP near 4.1 and saved in the region of 190 tonnes of CO2 a year, with the bulk of the capital over the like-for-like boiler-replacement cost met by the PSDS grant. The figures are illustrative and depend on your building, ground conditions, occupancy and funding position.

If a faster, lower-capital route fits better, compare commercial air-source heat pumps or a hybrid boiler-replacement retrofit, and for campus-scale schemes see heat networks and ambient loops. When you are ready, request a feasibility study, review the cost guide and funding routes, or read the heat pump FAQs.