Solar Panel Payback Calculator UK
Last updated 5 October 2026 · Prices based on the Ofgem price cap (October 2026 – December 2026)
Payback depends on how much your panels generate, how much of that electricity you use yourself, and the rate you get for exporting the rest. Adjust each input to match your home.
Solar panel payback calculator
A 4kWp system generates about 3,680 kWh a year, saving roughly £760 — payback in about 8.5 years.
- Generation / year
- 3,680 kWh
- Saving / year
- £760
- Payback
- 8.5 yrs
Generation = kWp × regional yield (920 kWh/kWp) × orientation factor 1. Saving = self-used kWh × 26.32p + exported kWh × 15p.
Typical yield by UK region (south-facing, kWh per kWp per year)
| Region | Yield | 4kWp generation |
|---|---|---|
| South of England / Wales | 1,000 | 4,000 kWh |
| Midlands | 920 | 3,680 kWh |
| North of England | 860 | 3,440 kWh |
| Scotland | 800 | 3,200 kWh |
Payback by self-consumption (4kWp, £6,500, Midlands)
| Self-use | Annual saving | Payback |
|---|---|---|
| 30% | £677 | 9.6 yrs |
| 50% | £760 | 8.5 yrs |
| 70% | £844 | 7.7 yrs |
What affects the cost
Self-consumption
Each kWh you use saves more than one you export.
Export tariff
SEG rates range from about 4p to 15p+.
Orientation and shading
East-west roofs generate about 15% less.
Electricity price
Higher prices shorten payback.
How to reduce the cost
- Run appliances in the middle of the day
- Shop around for SEG rates
- Consider a battery or solar diverter if you're out all day
- Clean panels if heavily soiled
Frequently asked questions
How long do solar panels take to pay back in the UK?
Typically 9–14 years, depending on self-consumption and export rates.
What is self-consumption?
The share of your generated electricity used in your home rather than exported.
Does a battery improve payback?
It raises self-consumption but adds cost, so payback can be longer unless you use time-of-use tariffs.
Sources and methodology
Energy prices come from the Ofgem price cap for Direct Debit customers (GB average). Installation costs are typical UK ranges from installer quotes and industry guidance, rounded. Savings use today's rates and do not predict future prices.