How long is the payback on solar panels?
Solar panels pay for themselves in roughly 6 to 10 years in the UK. The payback period is the installed cost divided by your annual saving, so a £7,000 system saving £900 a year pays back in around 8 years. After that, the electricity it generates is effectively free for the remaining 15 or more years of the system's life.
Payback is the single most useful number when judging solar, because it folds the cost, your savings and your export income into one figure. Here is how it is worked out and what shifts it.
How payback is calculated
Payback in years is the total installed cost divided by the total annual benefit. The annual benefit is the grid electricity you no longer buy (around 27p per kWh) plus the Smart Export Guarantee income on what you export (around 15p per kWh).
| Install cost | Annual saving | Payback |
|---|---|---|
| £6,000 | £500 | 12 years |
| £7,000 | £900 | About 8 years |
| £9,000 | £1,100 | About 8 years |
| £8,000 | £1,150 | About 7 years |
What makes payback faster
- A south-facing, unshaded roof generating near the regional maximum.
- High electricity usage during daylight hours.
- A battery, or an EV charged from solar, lifting self-use.
- A higher unit price on your electricity tariff.
What makes payback slower
- East, west or north-facing roofs, or heavy shading.
- Low electricity usage, so most generation is exported at the lower rate.
- Premium hardware that raises the upfront cost.
Estimate your own payback
Because payback depends on your roof, region and bills, a generic figure only goes so far. The SunSum calculator returns a payback range specific to your home in under a minute.
Frequently asked questions
- What is a good payback period for solar panels?
- In the UK, anything under 10 years is generally considered good. Well-sited systems with high self-use can pay back in 6 to 7 years.
- Do solar panels still save money after payback?
- Yes. Once the system has paid for itself, the electricity it generates is effectively free for the rest of its 25 year-plus life, aside from occasional maintenance.
Related questions
Indicative estimates based on UK average data. Last updated 26 May 2026.