The short answer for Cornwall: a 4kW south-facing system in Cornwall generates about 4,260 kWh a year on the EU's PVGIS model — about 5% more than London. Installed prices for that size run roughly £6,600–£7,800 on the government's 2025/26 cost data, and at October–December 2026 South West electricity prices (26.58p/kWh) it is worth roughly £800 a year without a battery, or £900 if a battery lets you use most of it yourself.
Cornwall has some of the best solar yields in England — and some of its hardest installation conditions: salt-laden coastal air, slate roofs, protected landscapes and a large share of homes heated without mains gas. All four shape a good Cornish quote.
How much a solar panel system generates in Cornwall
The table uses the European Commission's PVGIS tool for Truro: crystalline panels at a 35° pitch, with PVGIS's standard 14% allowance for system losses and the local horizon. Your installer's MCS estimate will differ a little because MCS uses its own irradiance tables and your actual pitch and shading, but the gap between places and orientations is what matters here.
| Roof faces | Per kW | 3kW system | 4kW system | 6kW system |
|---|---|---|---|---|
| South | 1,066 kWh | 3,200 kWh | 4,260 kWh | 6,400 kWh |
| East | 845 kWh | 2,540 kWh | 3,380 kWh | 5,070 kWh |
| West | 861 kWh | 2,580 kWh | 3,440 kWh | 5,170 kWh |
Annual output, PVGIS 5.3 (SARAH3 satellite data, 2005–2023) for Truro, fetched 23 September 2026. Actual output varies year to year.
Of the 8 areas we cover, Cornwall has the highest south-facing yield (Manchester is lowest at 886 kWh per kW). The seasons matter as much as the location: in December a 4kW system here makes about 137 kWh for the whole month, against 518 kWh in June — which is why a battery is mostly a summer and shoulder-season tool, and why nobody should promise you winter bills near zero.
Output rises as you head west: on the same PVGIS settings a south-facing kW produces about 1,050 kWh a year at Bude, 1,070 at Truro and 1,100 at Penzance — all well above London. The table uses Truro as the mid-point. Cornwall's summers also carry more of the year's output than its winters, so the value of a battery is highest here from April to September.
Coastal homes: within sight of the sea, ask for panels certified for salt-mist corrosion (IEC 61701) and stainless or suitably coated mounting hardware, and check the warranty doesn't exclude coastal exposure.
What solar costs and saves in Cornwall
There is no separate "Cornwall price" for solar — installers price by system size, roof and access — so the fairest benchmark is the government's own cost series. Across domestic installations registered with MCS between April 2025 and March 2026, the average installed cost was £1,955 per kW for systems up to 4kW and £1,645 per kW for 4–10kW, VAT included and batteries excluded.
| System | Output in Cornwall | Typical installed price | Year-one value, no battery | Simple payback |
|---|---|---|---|---|
| 3kW | 3,200 kWh | £4,900–£5,900 | £600 | 9–10 years |
| 4kW | 4,260 kWh | £6,600–£7,800 | £800 | 9–10 years |
| 6kW | 6,400 kWh | £9,900–£11,700 | £1,100 | 9–10 years |
Price range: DESNZ Solar PV cost data (published 28 May 2026), each size priced between the 4–10kW average (£1,645/kW) and the up-to-4kW average (£1,955/kW); bigger systems tend towards the lower figure per kW. Value: south-facing PVGIS output, 40% used in the home at the South West price-cap unit rate of 26.58p/kWh (1 October to 31 December 2026), the rest exported at 12p/kWh (the 12p rate several large suppliers pay their own import customers in September 2026). Payback ignores panel degradation, future price changes and inverter replacement.
Two things move those numbers more than anything about Cornwall itself. First, how much you use yourself: every unit you use saves 26.58p, every unit you export earns only what your export tariff pays — 12p in this illustration. Our illustration assumes you use 40% without a battery; with a battery taking that to around 70%, the same 4kW system is worth about £900 a year — but the battery adds several thousand pounds, so price it as its own line and judge it on its own payback (battery storage guide). Second, the export tariff: rates are set by suppliers, not Ofgem, and range widely — see the solar payback guide for current examples.
VAT on solar panels and batteries installed in homes is 0% until 31 March 2027 (how the relief works), so a quote that adds 20% VAT to a domestic install is wrong.
Cornwall homes and what they mean for your roof
Census 2021 counted 250,535 households in Cornwall: 26.5% semi-detached, 21.9% terraced, 37.2% detached and 12.8% flats or maisonettes, with 66.2% owner-occupied and 19.7% privately rented (England and Wales: 61.6% owned).
More than a third of Cornish homes are detached — well above the England average — and two-thirds are owner-occupied, so many roofs are large enough for a 5–6kW system if your use justifies it. Natural slate is common and slower to work on than concrete tile; ask how brackets will be fixed and who covers any broken slates.
Cornwall's heating is unusual: fewer than half of households heat by mains gas alone, 14% use only oil and 15% only electricity (Census 2021). For all-electric homes, solar offsets expensive daytime units directly; for oil homes, pairing solar with a future heat pump is worth planning — see oil to heat pump in Cornwall.
Planning permission in Cornwall
For houses in England, roof-mounted solar is permitted development — no planning application — as long as the panels stand no more than 20cm proud of the roof slope and don't rise above the highest part of the roof. The main exceptions are listed buildings (which need listed building consent), panels mounted on a wall that faces a road in a conservation area, and properties where the council has removed permitted development rights with an Article 4 direction. Blocks of flats have their own, similar permitted development rules, but panels on a shared roof still need the freeholder's consent. The rules were last amended on 27 August 2026.
Cornwall has around 145 conservation areas (council dataset), the Cornwall National Landscape covering roughly 27% of the county (Cornwall Council), and the Cornwall and West Devon Mining Landscape World Heritage Site. Cornwall Council's solar guidance says its Article 4 directions do not remove permitted development rights for solar panels: "none of these Directions remove permitted development rights for solar panels" (council guidance). In a conservation area or the World Heritage Site, panels on a wall facing a road still need permission, and listed buildings always need consent.
Connecting to the grid: National Grid Electricity Distribution (South West)
Cornwall's local network is run by National Grid Electricity Distribution in its South West licence area. Rural parts of the county sit at the end of long lines, and larger systems — or panels plus a big battery — are more likely to need G99 approval or an export limit than in a city, so ask early whether your design needs one.
For a typical home system the installer handles this. A single-phase installation up to 3.68kW of inverter capacity (16 amps per phase) is connected under the G98 process and the network operator is notified within 28 days of commissioning. Anything larger — including a bigger system, or panels plus a battery whose combined inverter capacity passes that limit — goes through G99, which needs the network operator's approval before installation and can add weeks. Ask your installer which route your design needs and whether an export limit is being applied.
Getting a quote in Cornwall
Tell us about your home
Postcode, property type and how you'd pay. Two minutes.
We pass it to one installer
If an accredited (MCS-certified) installer covers your area, we'll pass your enquiry to them, and only them. They can arrange a roof survey and quote.
Judge the quote
Check it against the figures on this page. If it's out of range, you can say no. No obligation at any stage.
How your enquiry is handled
- One installer introduction, fulfilling your request. If an accredited (MCS-certified) installer covers your area, we'll pass your enquiry to them, and only them — not a list of companies.
- No obligation, at any stage. You can say no at any point, including after the survey or the quote, and owe nothing.
- It costs you nothing. An installer may pay Great British Energy a referral fee if you go ahead, and that fee does not change your price.
- We are an independent guide, not an installer. Great British Energy Guide doesn't install anything and isn't the government body of a similar name. Your consent is recorded with the enquiry, as set out in our privacy policy.
Get your solar quote in Cornwall
One MCS-certified installer who covers your postcode. Nothing is shared until you submit.
What the quote should show
- The installer's MCS certificate number — needed for a Smart Export Guarantee tariff — and their consumer code (RECC or HIES).
- Named panel and inverter make and model, with quantities, and the MCS performance estimate for your roof in kWh a year. Every saving quoted to you should come from that estimate.
- Scaffolding stated as included or excluded, and any battery priced as a separate line.
- No VAT added on a home installation (0% until 31 March 2027), warranty terms split out, and, if financed, the total repayable next to the cash price.
The full checklist is on the solar quotes page.
Questions from Cornwall homeowners
Is Cornwall the best place in England for solar?
It is among the best. On PVGIS, south-facing output across Cornwall runs from about 1,050 kWh per kW a year in the north-east to about 1,100 in the far west, well above most of England. Coastal parts of Devon and the south coast are similar.
Do panels cope with sea air?
Good ones do, but check. Ask for modules tested to the salt-mist standard IEC 61701, corrosion-resistant fixings, and a warranty that doesn't exclude coastal sites.
Do I need planning permission in the Cornwall National Landscape?
Roof panels on a house are generally still permitted development there, but wall-mounted panels facing a road are not, and listed buildings always need consent. The planning section above has the council's guidance.
I heat with oil. Should I get solar or a heat pump first?
They work well together. A heat pump uses electricity, and solar offsets some of it from spring to autumn. If you're replacing an oil boiler in a home with no mains gas connection, the Boiler Upgrade Scheme pays £9,000 towards an air or ground source heat pump until 31 March 2027 — see the Cornwall heat pump page.
Other areas
- Solar in Birmingham
- Solar in Newcastle
- Solar in Manchester
- Solar in Bristol
- Solar in Sheffield
- Solar in Doncaster
- Solar in Nottingham
Heat pump pages: Birmingham, Bristol, Newcastle, Nottingham, Sheffield, Doncaster, and all heat pump quotes.
Sources
- European Commission JRC, PVGIS 5.3 — grid-connected PV, Truro, 1kWp crystalline silicon, 35° slope, 14% system loss, south/east/west, SARAH3 2005–2023; queried 23 September 2026.
- Office for National Statistics, Census 2021 tables TS044 (accommodation type), TS046 (central heating), TS050 (bedrooms) and TS054 (tenure), local authority level, via Nomis.
- DESNZ, Solar PV cost data, updated 28 May 2026 — domestic, mean cost per kW, Total Installed Capacity basis, 2025/26 (Official Statistics in development).
- 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).
- Ofgem, Smart Export Guarantee: tariffs must be above zero; suppliers with 150,000+ domestic customers must offer one. Supplier export rates checked on supplier websites, 23 September 2026.
- HMRC, VAT Notice 708/6: 0% on installing energy-saving materials in homes, 1 May 2023 to 31 March 2027.
- Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2 Part 14 Class A, as amended to 27 August 2026.
- Network connection thresholds (G98 up to 16A per phase — 3.68kW single-phase; larger systems G99): SP Electricity North West; find your operator via the Energy Networks Association.
- Cornwall Council, solar panels and planning permission, National Landscape management plan review; Cornwall Council conservation areas dataset (data.gov.uk).