The short answer for Carmarthenshire & Pembrokeshire: if your home is heated by oil or LPG and has no mains gas connection, the Boiler Upgrade Scheme pays £9,000 towards a heat pump for applications from 21 July 2026 to 31 March 2027 — £1,500 more than the standard grant. On today's prices a well-designed heat pump costs less to run than an oil or LPG boiler in the same house; how much less depends on its efficiency.
The Boiler Upgrade Scheme applies in Wales exactly as in England, including the £9,000 rate for air or ground source heat pumps in oil and LPG homes with no mains gas connection. In Carmarthenshire and Pembrokeshire around 32,000 households heat with oil alone — about 23–24% of homes — roughly seven times the England and Wales average — so the uplift is relevant to far more households here than in most of Britain.
How many Carmarthenshire & Pembrokeshire homes are off the gas grid
| Area | Households | Oil only | LPG only | Electric only | Mains gas only |
|---|---|---|---|---|---|
| Carmarthenshire | 81,761 | 23.7% | 3.2% | 4.0% | 54.3% |
| Pembrokeshire | 55,489 | 22.7% | 4.4% | 5.3% | 51.8% |
| England and Wales | 24,783,199 | 3.5% | 1.0% | 8.5% | 73.8% |
Census 2021, table TS046 (central heating), share of households using each fuel as their only type of central heating. Homes with two or more heating types are not in these columns, so the true number using some oil or LPG is higher.
Wales has its own funded scheme for lower-income households — Nest, under the Welsh Government's Warm Homes Programme; the Boiler Upgrade Scheme is separate and has no income test. If you might qualify for funded work, see the Carmarthenshire or Pembrokeshire grants pages before getting quotes.
Running costs: oil and LPG vs a heat pump in Carmarthenshire & Pembrokeshire
| Heating | Fuel bought a year | Price | Annual running cost |
|---|---|---|---|
| Oil boiler (85% efficient) | 17,650 kWh (about 1,710 litres) | 8.75p/kWh | £1,540 |
| LPG boiler (85% efficient) | 17,650 kWh | 9.50p/kWh | £1,680 |
| Heat pump, efficiency 2.78 (trial median) | 5,400 kWh electricity | 26.55p/kWh | £1,430 |
| Heat pump, efficiency 3.05 (trial upper quartile) | 4,920 kWh electricity | 26.55p/kWh | £1,310 |
| Heat pump, efficiency 3.5 (low-temperature design target) | 4,290 kWh electricity | 26.55p/kWh | £1,140 |
Illustrative 15,000 kWh of heat a year — a larger, older rural house; yours may be more or less, which is what the installer's heat-loss survey finds out. Oil and LPG prices: heating oil 90.01p a litre (DESNZ Quarterly Energy Prices, August 2026, including VAT), about 8.75p/kWh at 10.29 kWh per litre (DESNZ conversion factors 2025); LPG 9.5p/kWh (Energy Saving Trust fuel price assumptions, updated 22 September 2026). Electricity: South Wales direct-debit price cap, 1 October to 31 December 2026. Standing charges and boiler servicing excluded. Heat pump efficiencies: 2.78 is the median measured seasonal performance across 428 homes in the government's Electrification of Heat trial and 3.05 its upper quartile; 3.5 is the kind of figure a system designed to run at 45°C or below is designed to achieve, not a measured average.
Oil costs less per unit of heat than LPG, so the saving over oil is smaller than over LPG, and at the trial's median efficiency a heat pump is only modestly cheaper than oil. A low-temperature design running at an efficiency around 3.5 widens the gap considerably. Oil prices also swing more than capped electricity prices, and there are no deliveries or tank to maintain.
What it costs after the £9,000 grant
| Air source heat pump | |
|---|---|
| Typical installed price under BUS (median, April–June 2026) | £12,900 |
| Boiler Upgrade Scheme grant | −£9,000 |
| What you would pay | about £3,900 |
Median installed cost of an air-to-water heat pump under the Boiler Upgrade Scheme, April–June 2026 (lower quartile £11,128, upper quartile £15,627): DESNZ BUS Statistics: July 2026, published 27 August 2026. This is the middle figure across all installations — a small, well-insulated house can come in well under it; a large, older house needing new radiators and a cylinder can come in well over it.
Off-gas homes are often larger, older and less insulated than average, so expect quotes above the national median: a bigger heat pump, some larger radiators, a new cylinder and removing the oil tank. The extra £1,500 exists precisely because these jobs cost more.
Boiler Upgrade Scheme take-up to June 2026: Carmarthenshire 360 grants paid; Pembrokeshire 374 grants paid.
Carmarthenshire & Pembrokeshire homes: what to expect from the survey
Four in ten homes in both counties are detached, and many rural homes are old, stone-built and exposed to Atlantic weather. Heat loss through solid walls and wind exposure pushes up the heat pump size, so the room-by-room survey matters — and insulating first, where you can, lowers the cost of both the heat pump and running it.
On the coast, ask for corrosion protection on the outdoor unit suited to salt-laden air, and a warranty that doesn't exclude coastal sites.
The 31 March 2027 deadline
The higher rate is time-limited: it covers voucher applications up to 31 March 2027, after which oil and LPG homes return to the standard £7,500 unless the government extends it. A survey, design and voucher application take weeks, and installers get busier as a deadline approaches, so if your boiler is nearing the end of its life, getting a quote this autumn leaves room to decide without rushing.
Planning
Wales has its own permitted development rules, updated on 1 June 2026. An air source heat pump on a house is normally permitted development provided it meets the MCS 020(a) noise standard, the outdoor unit is no larger than 1.5 cubic metres, it isn't on a pitched roof, and there is no more than one unit (two on a detached house). Listed buildings need consent, and conservation areas and National Parks carry extra restrictions — check with the planning authority if you're in one.
Carmarthenshire has 27 conservation areas (council page); Pembrokeshire County Council has 24, and the Pembrokeshire Coast National Park Authority designates a further 15, including Tenby and St Davids (council page). Inside the National Park, and in the part of Carmarthenshire within Bannau Brycheiniog National Park, the Park Authority handles planning. Pembrokeshire also has Article 4 directions in Haverfordwest, Pembroke Dock, Goodwick and Lower Town Fishguard that restrict changes to roofs.
Do you qualify?
- £7,500 off an air source or ground source heat pump (£2,500 for air-to-air). From 21 July 2026 to 31 March 2027, an air source or ground source heat pump replacing oil or LPG heating in a home with no mains gas connection gets £9,000 instead (not air-to-air).
- England and Wales only. Owner-occupiers and private landlords can apply, including for second homes and business premises; most new-build homes and social housing can't.
- The heat pump must replace fossil-fuel heating (gas, oil, LPG, coal) or direct electric heating. Since 28 April 2026 an EPC is no longer mandatory — if the home doesn't have a valid one, the installer provides other evidence.
- The installer applies, not you. An MCS-certified installer requests the voucher and takes it off your price; Ofgem contacts you to confirm. It is a discount on the price, not a free installation — you pay the balance.
- There is no income test and no benefits requirement.
Source: GOV.UK, Apply for the Boiler Upgrade Scheme (updated 16 Sep 2026); DESNZ notice of grant values (effective 21 Jul 2026); Ofgem BUS guidance for property owners v5.1 (2 Jul 2026). Full detail: Boiler Upgrade Scheme guide.
Getting a quote in Carmarthenshire & Pembrokeshire
Tell us about your home
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If an accredited (MCS-certified) installer covers your area, we'll pass your enquiry to them, and only them. They can arrange a home survey, including a room-by-room heat-loss calculation.
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Get your heat pump quote in Carmarthenshire & Pembrokeshire
One MCS-certified heat pump installer who covers your postcode. They apply for the Boiler Upgrade Scheme on your behalf if you're eligible. Nothing is shared until you submit.
What the quote must contain is set out on the heat pump quotes page. For the national rules on the uplift, see the oil and LPG boiler replacement grant guide.
Questions from Carmarthenshire & Pembrokeshire homeowners
Does the Boiler Upgrade Scheme apply in Wales?
Yes — England and Wales, with the same £7,500 standard grant and £9,000 for an air or ground source heat pump replacing oil or LPG in a home with no mains gas connection, for applications up to 31 March 2027.
Is a heat pump cheaper to run than oil here?
At October–December 2026 South Wales prices, modestly at the trial's median efficiency and clearly with a well-designed low-temperature system. See the table above.
I'm in the Pembrokeshire Coast National Park. Who handles planning?
The Pembrokeshire Coast National Park Authority. Check with it before committing, especially if the house is listed or in a conservation area.
Can I get a heat pump free in Wales?
Only through income-based schemes such as the Welsh Government's Warm Homes programme. The Boiler Upgrade Scheme is a discount on the price, not a free installation.
Other areas
- Heat pumps in Birmingham
- Heat pumps in Sheffield
- Heat pumps in Bristol
- Heat pumps in Newcastle
- Heat pumps in Doncaster
- Heat pumps in Nottingham
- Oil to heat pump: Cornwall
- Oil to heat pump: Somerset
- Oil to heat pump: Fens & Peterborough
- Oil to heat pump: Northumberland
Sources
- GOV.UK, Apply for the Boiler Upgrade Scheme (updated 16 September 2026); DESNZ notice of grant categories and values (effective 21 July 2026); Ofgem, BUS guidance for property owners v5.1 (2 July 2026).
- DESNZ, Boiler Upgrade Scheme statistics: July 2026 (27 August 2026) — median installed cost 2026 Q2; redemptions paid by local authority, May 2022 to June 2026.
- Office for National Statistics, Census 2021 tables TS044 (accommodation type), TS046 (central heating), TS050 (bedrooms) and TS054 (tenure), local authority level, via Nomis.
- Ofgem, Changes to energy price cap between 1 October and 31 December 2026 (26 August 2026) and regional unit rates and standing charges; electricity at 0% VAT from 1 October 2026 to 31 March 2027 (HMRC).
- DESNZ, Quarterly Energy Prices table 4.1.1 (heating oil, August 2026); DESNZ conversion factors 2025 (burning oil energy content); Energy Saving Trust, Our data (LPG, updated 22 September 2026).
- Energy Systems Catapult for DESNZ, Electrification of Heat demonstration project, summary report (December 2024): median measured air source heat pump seasonal performance (SPFH4) 2.78, interquartile range 2.55–3.05, 428 homes.
- Welsh Government, Planning permission: heat pumps — permitted development rights updated 1 June 2026.
- Carmarthenshire County Council, conservation areas; Pembrokeshire County Council, conservation areas (checked 23 September 2026).