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.

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. The questions to put to ground source heat pump installers before a tender are set out in ground source heat pump installers: what to ask.

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.

How a typical install is sized

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.

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. 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

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. Tax relief works differently from what many guides say: a heat pump is part of a space or water heating system, which HMRC lists as an integral feature (special-rate plant), and full expensing covers main-rate plant only. The Annual Investment Allowance gives 100% relief up to its limit (£1 million), and companies can then claim a 50% first-year allowance on special-rate plant, with a 6% writing-down allowance on the rest. Confirm the treatment with an accountant. 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.

Funding routes in detail

The Boiler Upgrade Scheme reaches ground-source systems only within its capacity caps (45 kWth single, 300 kWth for a shared ground loop), so larger plant relies on other routes. 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 funds heat networks in application rounds (Round 12 closed on 25 September 2026; check gov.uk for the next round), and a heat network pairs naturally with central ground-source plant. PSDS has had no open application window since Phase 4 closed in November 2024, and gov.uk lists no further phase.

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. 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 a sound project is approached

You receive an itemised proposal with the full model attached. The point is that you should never be asked to fund something underground on trust; you fund it on evidence.