Quick answer: a typical 4 kWp UK residential solar system costs £6,500–£9,500 fully installed in 2026, including the 0% VAT rate that runs until 31 March 2027. Most families pay £7,500–£8,500. Add £4,000–£6,000 if you want a battery. Below we break down what drives the variance and why "average" prices are misleading.
Installed prices by system size
Pricing scales roughly with system size, but per-kWp installed cost actually drops as the system gets bigger — fixed costs (scaffolding, electrician day rate, paperwork) get spread over more kWp.
| System size | Panels | Installed price | £/kWp |
|---|---|---|---|
| 3 kWp | 7–8 | £5,200 – £7,500 | £1,733 – £2,500 |
| 4 kWp | 10 | £6,500 – £9,500 | £1,625 – £2,375 |
| 5 kWp | 12–13 | £8,000 – £11,000 | £1,600 – £2,200 |
| 6 kWp | 15 | £9,500 – £13,000 | £1,583 – £2,167 |
| 10 kWp | 24–26 | £14,500 – £19,500 | £1,450 – £1,950 |
What drives the variance?
The £6,500–£9,500 range for a 4 kWp system isn't random. Six factors explain almost all of it:
- Panel brand and tier. Tier-1 monocrystalline (REC, Q CELLS, JA Solar, Trina, LONGi) costs more than Tier-2 — typically £150–£250/panel difference. Premium brands (REC Alpha, Maxeon) push it further.
- Inverter choice. A basic string inverter (Solis, Growatt) is the cheapest. Hybrid (battery-ready) inverters add £400–£800. Microinverters (Enphase) or power optimisers (SolarEdge) add £600–£1,200 — worth it for shaded or complex roofs, overkill otherwise.
- Scaffolding access. Front and back of house, narrow lanes (London terraces especially), or anything above two storeys adds £300–£600. Bungalows are the cheapest.
- Roof complexity. A single south-facing pitch is the cheapest. East/west split arrays cost slightly more (longer cable runs). Hip roofs, dormers and listed-building complications add labour.
- Mounting type. Slate roofs need slate hooks (slightly more expensive than tile clamps). Flat roofs need ballasted frames. Roof-integrated panels are the most expensive option but the prettiest.
- Geography. London and South East England runs ~5–10% higher than the national average. North East and parts of Wales run slightly below. This is mostly driven by labour day-rates and travel time for installers.
What about battery storage?
Battery prices have come down significantly in the last 24 months. As of 2026:
- 5 kWh battery (e.g. GivEnergy, Solax, FoxESS): £4,000 – £5,000 fully installed.
- 10 kWh battery: £5,500 – £7,000 fully installed.
- 13.5 kWh Tesla Powerwall 3: £8,500 – £10,500 fully installed.
The economics: a battery raises self-consumption from ~50% to ~80%, adding roughly £200–£350/yr to your savings. At a £4,500 install cost, that's a 13–22 year battery-only payback, which sits awkwardly against a typical 10-year battery warranty.
Our take: if you're cash-constrained, a battery-ready hybrid inverter installed now lets you add storage cheaply later when prices drop further. If you're at home during the day or have an EV, batteries are less essential than the marketing implies.
Hidden costs to watch for
A reputable MCS-certified installer will price these in upfront. If they're missing from your quote, ask:
- Scaffolding — sometimes shown as a separate line
- Bird mesh — £150–£300 for full perimeter, recommended in most areas
- DC isolator and AC isolator — should always be included
- Consumer unit upgrade — older boards (pre-2008) often need an upgrade or new sub-board, £300–£700
- G99 commissioning — required for systems above 3.68 kWp single-phase, included in MCS-spec quotes
- EICR / electrical certification — your installer should issue this; if it's not mentioned, that's a red flag
Why 0% VAT matters so much
The 0% VAT rate on residential solar (and battery storage when installed alongside) is in effect until 31 March 2027. After that, the VAT rate is currently scheduled to revert to 5%.
In practical terms: a £8,500 system today costs you £8,500. The same system on 1 April 2027 — assuming no other price movement — would cost £8,925. Booking before the cutoff is worth an extra £400–£700 on most installs.
"0% VAT until March 2027 is the single biggest tailwind for UK residential solar in years. Booking early in the window — not late — gives installers time to schedule and gives you time to get your SEG tariff sorted."
What we don't include in our pricing
We're transparent about what isn't part of our quoting flow:
- Government grants or ECO4-style funding. We don't offer these. Our installers quote real prices with the 0% VAT discount baked in.
- "Free solar" leases. These exist in the UK market but typically cap your savings to a small share of generation while the lease company keeps the SEG payments. Not something we recommend.
- Cold-call sales. Our quote tool sends pricing by email — no high-pressure sales calls unless you ask.
Frequently asked
What's the average cost of solar panels in the UK in 2026?
A 4 kWp residential system — the most popular UK size — costs £6,500–£9,500 fully installed in 2026, including 0% VAT. The mid-point most homeowners pay sits around £7,800.
How much does a battery add to the cost?
A 5 kWh battery typically adds £4,000–£5,000 fully installed; a 10 kWh battery £5,500–£7,000. Hybrid inverter systems (battery-ready from day one) add £400–£800 versus a string-only inverter.
What drives the price variance?
Panel brand, inverter brand, scaffolding access, roof complexity, postcode, and whether you need power optimisers for shading. Battery size is the biggest single driver if you're including storage.
Want a precise number for your home? Our 60-second quote tool matches you with MCS-certified installers in your postcode and sends you real prices — not estimates.