Solar System Cost UK: Prices by Size (2026)
How much does a solar system cost in the UK? The answer depends heavily on size. This page compares every common system size, from a typical 4kW home install up to a 50kW commercial rooftop, with current 2026 pricing, output, and payback.
| Size | Cost range | Panels | Annual kWh | Payback | Best for | |
|---|---|---|---|---|---|---|
| 4kW | £6,600–£8,500 | 8–14 | ~3,400 | 11–13 yrs | 3–4 bedroom home, typical UK household | Details → |
| 7kW | £11,000–£13,000 | 14–26 | ~6,300 | 9–11 yrs | 4–5 bedroom home, or small business with moderate daytime use | Details → |
| 12kW | £14,000–£17,000 | 24–44 | ~11,122 | 6–8 yrs | Large home, home-office setup, or small commercial property | Details → |
| 15kW | £17,000–£20,500 | 30–56 | ~13,903 | 6–8 yrs | Large home with EV charging, small hotel, or small commercial unit | Details → |
| 20kW | £22,000–£28,000 | 40–74 | ~18,537 | 6–8 yrs | Small commercial property, farm outbuilding, workshop, or large estate | Details → |
| 50kW | £55,000–£70,000 | 100–185 | ~46,343 | 6–8 yrs | Commercial rooftop, warehouse, factory, medium farm, hotel | Details → |
How to Choose the Right Size
Bigger is not always better. A system that generates more than you use exports the surplus at lower rates than you pay to import, which stretches the payback period. Size to your daytime consumption, not your total annual usage.
- Small household, modest bills: 4kW is the sweet spot, fits within G98 (no DNO waiting period), covers most daytime use, battery optional
- Family home with EV or heat pump: 7kW usually justifies the G99 wait
- Large home, multi-EV, home office: 12–15kW if roof space allows
- Commercial rooftop: 20–50kW sized to daytime business load
Sources
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.
Related Guides
Solar Savings Calculator
Estimate your savings, payback period, and annual generation by region and usage.
Solar Panel Costs
Full cost breakdown and payback periods.
Solar Panel Payback
Payback periods by system size, ROI calculations, and how to maximise returns.
Solar Panel Output
How much electricity solar panels produce by system size in the UK.
Are Solar Panels Worth It?
Honest pros, cons, and payback analysis for UK homes.