Solar panel prices by system size (Cornwall, 2026)
| System | Typical property | Typical installed price |
|---|---|---|
| 3kW (7–9 panels) | 1–2 bed home, low usage | £4,500–£6,500 |
| 4kW (around 10 panels) | 3-bed home — the Cornwall sweet spot | £6,000–£8,500 |
| 6kW (around 15 panels) | Larger home, EV or heat pump | £8,500–£11,000 |
| 4kW + 5kWh battery | Most common 2026 spec | £9,500–£13,500 |
| 6kW + 10kWh battery | High-usage home, EV + heat pump | £12,500–£17,500 |
| Commercial / farm 30kW+ | Barns, warehouses, hospitality | Bespoke (G99 included) |
All prices include 0% VAT (in force on domestic solar and battery installations until 31 March 2027) and assume an MCS-certified install with Smart Export Guarantee setup. Your matched installer confirms a firm written price after a site survey — request a free quote and you'll usually have a survey arranged within one to two weeks.
Battery storage add-on costs
| Battery | Capacity | Typical fitted price |
|---|---|---|
| GivEnergy (AC- or hybrid-coupled) | 5–9.5kWh | £5,500–£7,500 |
| Tesla Powerwall 3 (incl. Gateway) | 13.5kWh | £8,500–£12,000 |
| Enphase IQ Battery | 10kWh | £8,500–£10,000 |
Batteries change the economics more than any other option — see our full guide to solar battery storage in Cornwall, and the detailed Tesla Powerwall Cornwall cost breakdown for what the premium option actually buys you.
What moves the price up or down
- Roof type. Slate — the default across much of Cornwall — adds 15–20% over concrete tile, because each slate is lifted to fit roof hooks and breakages need replacing. Budget an extra £500–£1,200 on a 4kW system. Scantle slate in Penwith and on the Lizard needs the most careful work.
- Scaffolding. A straightforward two-storey semi is cheap to scaffold; a three-storey townhouse, a coastal property with awkward access, or a narrow St Ives lane where vehicles can't get close all add cost.
- Battery and inverter choice. A basic string inverter is cheapest; a hybrid inverter (battery-ready) adds a little now and saves a retrofit later. Inverters last 10–15 years, so a replacement mid-life is part of the honest maths.
- Grid connection. Systems up to 3.68kW per phase are notified after install (G98). Bigger systems need G99 DNO pre-approval — no extra cost on most domestic jobs, but it adds 4–8 weeks of lead time and can constrain export on rural single-phase lines.
- Coastal exposure. Within a couple of miles of the coast, marine-grade rails, stainless fixings and bird-proofing mesh are baseline spec — a modest cost that protects yield and hardware for decades.
What you get back: payback and SEG earnings
Cornwall yields around 1,000–1,080 kWh per kWp per year — above the UK average thanks to southerly latitude and open Atlantic horizons. Honest payback figures:
- Domestic, no battery: 8–12 years
- Domestic with battery, self-consumption maximised (EV, heat pump, immersion): 7–10 years
- Commercial and farm: 5–8 years, thanks to high daytime self-consumption
Surplus electricity earns via the Smart Export Guarantee: standard fixed tariffs pay roughly 4–15p/kWh, and time-of-use tariffs like Octopus Flux can reach 25–30p/kWh at peak if you have a battery. With panels warranted for 25+ years, that leaves well over a decade of effectively free electricity after payback. Anyone quoting a 4–5 year domestic payback is misleading you — walk away.
How to pay less (honestly)
- Get two to three written quotes. Prices genuinely vary between MCS-certified installers — this is the single biggest saving available. Tell us the job once via the quote form and we'll match you rather than you ringing round.
- Install before 31 March 2027. The 0% VAT window on domestic solar and batteries runs to then — afterwards it reverts to the reduced rate, adding hundreds to a typical install.
- Size for your usage, not your roof. A well-sized 4kW system with high self-consumption beats an oversized 6kW system exporting at 4p/kWh. Not sure? Run through our roof suitability checklist first.
- Think battery-ready even if not battery-now. A hybrid inverter costs a little more today and saves an expensive retrofit if you add storage later.
Frequently asked questions
Does the price vary across Cornwall?
A little. The baseline is similar county-wide, but slate-heavy and access-awkward areas (Penwith, the Lizard, old-town St Ives) tend toward the top of the ranges. See your local page for detail: Truro, Falmouth, Bodmin, Launceston, Liskeard, St Austell, Redruth, Penzance, Helston, St Ives, Newquay, Wadebridge and Camborne.
Are there any grants in 2026?
The main incentives are 0% VAT to March 2027 and the Smart Export Guarantee. ECO4 funding may apply for low-income households, and businesses and farms can use the Annual Investment Allowance (100% first-year capital allowance on plant and machinery, subject to the AIA cap). Your matched installer will confirm what applies.
What about ongoing costs?
Panel cleaning (from £75 a visit — worth it on the coast, where grime and gull droppings cost 5–15% of yield), an inverter replacement at year 10–15, and possibly a small insurance premium bump. That's it — panels themselves are essentially maintenance-free.
Why do quotes vary between companies?
Panel and inverter brands, scaffolding arrangements, how busy the installer is, and how honestly they've surveyed the roof. This is exactly why we exist: tell us the job once and we match you with a vetted local MCS-certified installer suited to your property — no lead-aggregator cold-call carousel.