What is the payback period for commercial solar in the UK?
The payback period for UK commercial solar in 2026 is 3.5–6 years for well-sized systems on high-consumption sites, calculated after 100% Full Expensing. Larger systems (500 kWp+) on 24/7 sites often pay back in under 4 years; smaller systems on part-time premises take 6–8 years. The 25-year IRR sits at 15–25% for most projects.
Last updated 26 July 2026.
Key facts at a glance
| Fast payback (24/7 site, 500 kWp+) | 3.5–4 years |
|---|---|
| Typical payback (mid-size) | 4.5–6 years |
| Slow payback (low daytime demand) | 6–8 years |
| Panel warranty | 25 years |
| Inverter warranty | 10–12 years |
| 25-year IRR (well-sized) | 15–25% |
Levers that shorten payback
Higher grid tariff, higher self-consumption %, capex funded with Full Expensing rather than lease/PPA, larger system size (better £/kWp), and adding EV charging or battery storage to lift on-site consumption. Sites moving from single- to double-shift often halve payback.
Levers that lengthen payback
Low daytime demand (weekend-only occupation), export-limited grid connection, poor roof orientation, or over-sizing beyond consumption. In these cases, right-sizing or a PPA structure usually restores the economics.
Related reading
FAQ
What's a good payback period for a business solar system?
Under 6 years is considered good in 2026. Under 4 years is excellent and typically achievable on 24/7 sites above 250 kWp.
How does payback compare to other business investments?
A 4-year payback equates to a 25% simple annual return — competitive with most SME capital investments and lower risk given the fixed 25-year asset life.
Request your free feasibility review
Share a few details and our team will send a no-obligation review of your site — indicative system size, annual generation, savings and payback. Prefer to explore numbers yourself first? Run the calculator or contact us directly.
- MCS & RECC accredited installer
- Response within one working day
- No cost, no obligation