Solar Panel Payback Period Calculator
Calculate how many years until your solar panel system pays for itself.
Factor in cost, energy savings, and export tariffs.
The solar payback period is the time it takes for energy savings to equal the upfront installation cost. After that point, all savings are pure profit.
Simple payback formula: Payback (years) = total system cost / annual savings
Annual savings formula: Annual savings = (self-consumed kWh × electricity price) + (exported kWh × export tariff)
Worked example:
- System cost: £8,000 (10 panels, 4 kW)
- Annual production: 3,500 kWh
- Self-consumption (50%): 1,750 kWh at £0.28/kWh = £490
- Export (50%): 1,750 kWh at £0.15/kWh = £262.50
- Total annual savings: £752.50
- Payback = £8,000 / £752.50 = 10.6 years
Typical payback periods:
- UK: 8–12 years
- Southern Europe: 5–8 years
- US Sun Belt: 5–8 years
- US Northeast: 8–12 years
After payback: Solar panels typically last 25–30 years with minimal degradation (~0.5% per year). A 10-year payback system will generate 15–20 more years of free electricity.
Self-consumption rate: Homes with higher daytime electricity use (working from home, EV charging, heat pumps) benefit most from solar. Pairing with a battery increases self-consumption from ~30–40% to 70–90%.