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 | £5,500–£7,000 | 8–14 | ~3,800 | 7–9 yrs | 3–4 bedroom home, typical UK household | Details → |
| 7kW | £8,500–£10,500 | 14–26 | ~6,488 | 6–8 yrs | 4–5 bedroom home, or small business with moderate daytime use | Details → |
| 12kW | £12,000–£15,000 | 24–44 | ~11,122 | 6–8 yrs | Large home, home-office setup, or small commercial property | Details → |
| 15kW | £17,000–£20,000 | 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 | 5–7 yrs | Small commercial property, farm outbuilding, workshop, or large estate | Details → |
| 50kW | £55,000–£70,000 | 100–185 | ~46,343 | 5–7 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
Related Guides
- Solar battery cost UK
- Best Octopus tariffs for solar
- DNO application guide (G98 vs G99)
- Compare solar installers
Sources
JR
John Rooney• Solar Energy Editor
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He fact-checks all content against official MCS and Ofgem data and maintains relationships with MCS-certified installers across the UK.
MCS data verifiedIndependent research3+ years covering UK solar