Solar panel pricing has continued to fall through 2025 and into 2026 — panel costs are at their lowest since the FiT era. Inverter and battery prices have also softened. Here's what 2026 actually looks like.
Domestic systems
- 3 kW system, no battery: £4,999 to £6,200 fitted
- 4 kW system, no battery: £6,500 to £8,500 fitted
- 6 kW system, no battery: £8,200 to £10,800 fitted
- 4 kW + EcoFlow 5 kWh: £11,200 fitted
- 4 kW + Tesla Powerwall 3: £14,500 fitted
- 6 kW + Tesla Powerwall 3: £15,800 fitted
Variance comes from roof complexity (scaffolding, tile cuts), panel choice, and inverter type (string vs hybrid vs microinverter).
What you're paying for
A typical £8,000 4 kW install breaks down roughly: - 11 panels at £160 each: £1,760 - Inverter (SolarEdge or GivEnergy): £1,200 - Optimisers (where shading needs them): £400 - Mounting hardware and bracketry: £450 - DC and AC cabling, MC4 connectors: £180 - Scaffolding hire (3 days): £600 - Labour (2 engineers, 1 day): £900 - DNO paperwork, MCS cert, SEG registration: £350 - Margin and overhead: ~£2,200
So material + labour is roughly 75% of price, with the rest going to overheads, paperwork, and the warranty obligation.
Commercial systems (per kWp)
- 50–100 kWp: £950–£1,100 / kWp
- 100–250 kWp: £820–£950 / kWp
- 250–500 kWp: £750–£850 / kWp
- 500+ kWp: £680–£780 / kWp
Add Annual Investment Allowance (AIA) tax relief and the effective cost drops 19–25% for taxable companies.
What's NOT included in most quotes
- Roof repairs (often needed on systems over 15 years old)
- DNO substation upgrade fees (commercial only — varies £0 to £40k)
- Bird mesh (£499 typical add-on)
- EV charger (£799 fitted typical)
- Heat pump bundle (separate £8,500 install)
Honest cost-saving advice
Quotes vary wildly because installers vary in quality. The cheapest quote is rarely the right one — most installers cut corners on optimisers (omitting them where shading exists) or use unbranded panel/inverter combinations that don't hold their performance.
Get three quotes. Verify MCS certification on each. Ask each to walk you through their PV*SOL or Aurora simulation. The right installer will quote middle-of-the-pack on price but show their working.