The amount
On GOV.UK’s “what you can get” page, read on 8 October 2026, ground source and air source heat pumps are listed at the same figure: £7,500. The extra £1,500 (a total of £9,000) applies to an air or ground source heat pump where the property is heated by oil or LPG and has no mains gas connection, for applications up to 31 March 2027. A home on direct-electric heating without mains gas gets £7,500.
The size limits are 45 kWth for a single heat pump and 70 kWth where several are installed together, which comfortably covers homes.
As with air source, there is no grant for hybrid systems and you cannot use it to replace existing low-carbon heating. The ownership, property-type and new-build tests are the same as in the air source guide and on the eligibility page; there is no EPC requirement since 28 April 2026.
Which ground source grant would apply to you?
Six quick answers; contact details are optional and only needed if you want us to reply by email. Indicative only — your MCS installer checks eligibility and Ofgem makes the decision.
Likely £7,500
Owner-occupied home in England on mains gas replacing the boiler with an air-to-water heat pump.
Rules: GOV.UK “Apply for the Boiler Upgrade Scheme” and Ofgem’s property owner guidance (v5.1). Grant bands from the notice of grant categories updated 21 July 2026.
Trench, borehole or shared loop
Ground source covers a family of systems that are paid at one rate but built differently:
| Layout | What it is | Grant |
|---|---|---|
| Horizontal trenches | Pipework buried in trenches across the garden. The Energy Saving Trust puts a typical cost around £15,000 where the loop is buried in trenches. | £7,500 (£9,000 oil/LPG, no mains gas) |
| Vertical borehole | One or more drilled holes. Needs access for a drilling rig but little surface area. | Same |
| Water source | Heat taken from a pond, lake or similar water body. | Same |
| Shared ground loop | One loop serving several homes, each with its own heat pump. Limit 300 kWth in total. | Same, per property |
The line items that make ground source dearer than air source are mostly ground-works, which is why it matters whether your plot can take a trench or a borehole before you compare quotes. The ground source cost page breaks them down.
The 6-month voucher
The process matches the one for air source: your MCS-certified installer applies to Ofgem, Ofgem emails you to confirm (guidance expects a reply within 14 days), and the grant is deducted upfront on the quote. The difference is the voucher’s validity: 6 months for ground source against 3 months for air source and biomass (Ofgem guidance v5.1). That helps where drilling slots or ground conditions delay the job. A step-by-step is on how to apply.
Illustrative example
| Item | Standard | Oil or LPG, no mains gas |
|---|---|---|
| Median installed cost (DESNZ, 2026 Q3, including the grant value) | £34,630 | £34,630 |
| Grant deducted | − £7,500 | − £9,000 |
| Balance to pay | £27,130 | £25,630 |
82% of ground source grants paid went to off-gas properties and 84% to rural ones (DESNZ statistics, end of September 2026). In practice ground source is mostly chosen where there is land and no gas main, which is the setting where the larger £9,000 band can apply. Change the numbers below to match your own quote.
Ground source: cost after the grant
No details needed. Change any figure to match your own quote or bills. Results are indicative — an MCS installer’s heat-loss survey and written quote are what count.
£27,130
Payable by you on this quote. The grant is deducted on the quote and invoice — you never receive it as cash.
Default quote = the official median installed cost for 2026 Q3 (DESNZ, published 29 October 2026), which includes the grant value. VAT on installing a heat pump in a home is 0% until 31 March 2027, then 5%.
Planning and permits
In England, installation of a ground source heat pump can be permitted development under its own class of Part 14 (Class C for ground source, with its own conditions), not Class G; Class G and its limits are for air source units (noise to 37.0 dB(A) at the assessment position, unit size and siting). The planning page covers the air source rules and their exceptions. For a borehole, whether any consent or permit is needed from a regulator depends on the type of loop and site; we have not been able to confirm a general rule from a primary source this session, so ask the installer to state in writing which consents they will obtain and who pays for them. Wales and Scotland have their own planning rules.
Combining the grant with other support
- VAT: 0% VAT on installing a heat pump in a home until 31 March 2027, then 5%. Check that the quote shows the VAT treatment line by line.
- Loan: the Warm Homes Loan Scheme rules cap a ground source loan at £35,000 before the grant is deducted and expressly allow a borrower to combine a loan with a Boiler Upgrade Scheme grant. Loans come from participating lenders on their own terms, so compare the rate and total repayable. See heat pump finance.
- Other funding for the same heat pump: GOV.UK says you cannot claim where the property has already been given government funding or support for a heat pump. See other heat pump funding.
Ground source or air source?
With the grant identical, the choice comes down to cost, space and running efficiency. The DESNZ median shows ground source at £34,630 against £12,826 for air source. The ground loop’s steadier source temperature can mean cheaper running, but the extra up-front cost means payback depends on the plot and fuel replaced. Our running cost page shows the arithmetic, and 421 of 96,611 paid grants were for biomass, which is a different decision again (see biomass boiler grant).
Honest questions about the ground source grant
“Ground source costs far more, so the grant must be bigger.”
The grant is the same as for an air source heat pump: £7,500, or £9,000 for oil and LPG homes with no mains gas. The scheme does not pay more for the more expensive technology. The DESNZ median installed cost was £34,630 for ground source against £12,826 for air source (2026 Q3, both including the grant value), so the balance after the grant is larger.
The higher running efficiency of a ground loop is real, but it takes years to offset a higher installation cost, and not every plot can take a loop at all.
“I do not have the garden for it.”
A single home needs space for trenches or a borehole. Boreholes are vertical, so they need far less surface area. The scheme also supports shared ground loops that serve several properties, up to 300 kWth in total, which suits terraces, new developments and some communities.
“Why does the voucher last longer?”
Ground source vouchers are valid for 6 months rather than 3. Ofgem gives no reason, but ground source work involves groundworks that can take longer to schedule and complete.
What happens next
Ground source quotes should come after a visit to the plot. Ask each installer to state the loop type, the length of pipe or borehole depth, where the spoil goes and what is reinstated. Your enquiry comes to SEO-DONS LTD, the publisher of this guide, and we reply by email.