Ground-Source Heat Pumps (Commercial): Commercial heat pump installers

Why ground-source is the long-game choice, and why the installer matters most here

Ground-source is the heat-pump technology that rewards patience and good engineering. Instead of pulling heat from outside air, it draws on the stable temperature of the ground through boreholes or horizontal loops, and because that source barely changes through the seasons the efficiency holds up even on the coldest day of the year when air-source dips. For a commercial building that runs year-round, a care home, a hospital, a hotel, a leisure centre, that stability is worth a great deal. As commercial heat pump installers we are clear-eyed about ground-source: it costs more up front and it takes longer to deliver because of the ground works, but on the right building it produces the highest and most stable performance of anything we install, an SCOP often above 4.0 all year, plus the bonus of low-cost cooling in summer.

This is also the technology where the choice of installer matters most, because so much of the risk and value sits underground where you cannot inspect it after the fact. The ground array has to be designed from real ground data, the drilling has to be done properly, and the system has to be balanced so the ground does not gradually cool over years of operation. Get that wrong and the headline efficiency erodes; get it right and the borehole field can last for decades while the heat pump itself runs reliably. Our job is to bring that rigour to a piece of plant most buyers will never see.

There is a thermal-balance point that separates competent ground-source design from the rest. If a building only ever extracts heat from the ground in winter and never returns any in summer, the ground around the boreholes can cool slowly over the years and the efficiency drifts downward. On a building that also needs cooling, that is a gift, because rejecting summer heat back into the array both delivers that cooling cheaply and recharges the ground for the next heating season. Designing the array to stay in thermal balance over its life is exactly the kind of long-horizon engineering that a serious commercial heat pump installer thinks about and a price-led contractor does not, and it is the difference between a system that holds its performance for decades and one that quietly fades. It is also why the cheapest borehole quote is so often the most expensive choice over twenty years: an under-sized array drilled to save a few boreholes will draw the ground down and erode the SCOP you were sold, and you cannot drill more boreholes once the building is finished and the car park is back in place.

What a typical install looks like and how we size it

A commercial ground-source install from us usually sits in the 50 to 1,000 kW thermal range, served by a borehole array, typically 100 to 200m deep, or horizontal ground loops where land allows, with the ground or borehole field footprint varying hugely from site to site. Heat delivered runs from about 120,000 to 2,500,000 kWh a year, removing in the region of 22 to 450 tonnes of CO2 annually. Sizing is driven by peak heat-loss and annual demand, never floor area, so we begin with a heat-loss survey and at least twelve months of consumption. Crucially for ground-source we also recommend a ground investigation and thermal response test before final design, so the array is matched to the actual thermal conductivity of your ground rather than a textbook assumption. As with all our work we design to keep flow temperatures low, because every degree shed lifts the SCOP, and we specify to BS EN 14825 and 14511 so the performance is comparable across suppliers.

The choice between a borehole array and horizontal ground loops comes down to the land you have. Boreholes, typically 100 to 200m deep, need only a modest surface footprint and suit constrained urban or built-up sites, but the drilling is the larger cost. Horizontal loops are cheaper to install where there is open ground to trench, but they need a substantial area and are more affected by surface seasonal temperature than deep boreholes. We size the array from the thermal response test results so the ground can supply the design load year after year without being over-drawn, and we set the number and spacing of boreholes accordingly rather than to a rule of thumb. Where summer cooling is part of the brief, the array is sized to handle both the heating extraction and the cooling rejection, which is one of the reasons ground-source whole-life economics can be so strong on a building that needs both.

Costs, payback and tax relief

Ground-source is the largest capital commitment we quote, typically £150,000 to £2,000,000 or more, with a longer simple payback around 11 years reflecting the drilling cost. It earns that premium where the building runs year-round or needs summer cooling, and especially where grant funding meets the capital. A building that is occupied and heated every day of the year extracts far more value from a high, stable SCOP than one that sits empty for long stretches, which is why care homes, hospitals, hotels and leisure centres tend to be the strongest ground-source candidates and why a seasonally occupied building is often better served by air-source. The whole-life sum is what matters here: the higher capital is spread across two decades or more of the lowest running cost of any heat-pump technology, plus, on the right building, the value of summer cooling delivered almost for free. The tax position is the same powerful lever as for any heat pump: full expensing gives companies a 100% first-year deduction with no cap, made permanent from April 2026 and worth up to 25p in the pound at the 25% corporation-tax rate, while unincorporated businesses use the Annual Investment Allowance up to one million pounds. Where the system exports surplus on-site electricity the Smart Export Guarantee can apply, though ground-source value is overwhelmingly in avoided import and in the free summer cooling. We always model ground-source and air-source side by side from your data so you see the whole-life cost of each before deciding, and our cost guide lays out the comparison.

Funding routes in detail

Ground-source is often the technology where grant funding makes the business case, so getting the route right is central to what we do. The Boiler Upgrade Scheme remains domestic-only and irrelevant to your building. For public bodies the Public Sector Decarbonisation Scheme via Salix is the obvious route and a natural fit for ground-source, because it funds the cost over and above a like-for-like fossil replacement and takes a whole-building view, which suits a high-capital, high-efficiency system on a year-round public building such as a leisure centre or hospital. Multi-building campuses, councils and large mixed-use developments may fit the Green Heat Network Fund, which can cover up to 50% of eligible costs and pairs naturally with central ground-source plant. Any taxpaying business can stack full expensing or the Annual Investment Allowance on top. We map your eligibility and build the application around the design, working to the competitive windows and completion deadlines each scheme sets. The full picture is on our grants and funding page.

Compliance and sector considerations

Ground-source adds an environmental and ground-works compliance layer on top of the usual heat-pump rules. Borehole drilling requires Environment Agency awareness: open-loop systems that abstract and discharge groundwater need an abstraction and discharge permit, while closed-loop systems do not but must follow the EA closed-loop guidance. We design to CIBSE TM51 ground-source guidance and MIS 3005 design principles, recommend a ground investigation and thermal response test before committing the final array, and where the system is 45 kWth or below we carry MCS certification for grant access. Borehole arrays may require planning depending on scale. The standard heat-pump compliance still applies: F-Gas certified refrigerant handling, BS EN 378 safety standard, BS EN 14511 and 14825 performance ratings, and an early DNO conversation because large plant adds significant electrical load and a supply upgrade can be the longest-lead item alongside the drilling itself.

How we approach this kind of project

Because ground-source buries most of its value, our approach front-loads the engineering. We model the project from your half-hourly meter data and twelve months of consumption, run the heat-loss survey, and where the scheme warrants it commission a thermal response test so the array is sized on measured ground performance, not a guess. We model air-source and ground-source side by side so you can see exactly what the borehole premium buys you in whole-life terms before you commit a penny. We design for low flow temperatures to protect the SCOP, survey emitters so the building can give the heat up efficiently, and submit the G99 grid application and any EA paperwork early to keep the long-lead items moving in parallel. You receive a fixed-price proposal with the full model attached, and the install is covered by an insurance-backed warranty. The point is that you should never be asked to fund something underground on trust; you fund it on evidence.

An illustrative example

As an illustrative composite based on the kind of work commercial heat pump installers carry out, and not a real named client: a council-owned leisure centre with a swimming pool, sports hall and year-round heating and hot-water load, sitting on an end-of-life gas boiler, had a 450 kW ground-source system installed on a borehole array, with Public Sector Decarbonisation Scheme funding meeting the bulk of the capital over the like-for-like boiler replacement. At an SCOP of around 4.1 it delivered roughly 1,050,000 kWh of heat a year and saved in the region of 190 tonnes of CO2, removing gas from the main plant entirely, while the same plant provided low-cost summer cooling support for the sports hall. The stable year-round efficiency and the grant funding together made the case. The figures are illustrative and depend on your building, ground conditions, funding and consumption.

If the capital or lead time of ground-source does not suit, our commercial air-source page covers the faster, lower-capital route, and for buildings with stubborn high-temperature emitters our hybrid retrofit page may fit. When you are ready, see the cost guide, the funding routes, the commercial heat pump FAQs, or request a feasibility study from your meter data.