The return on investment (ROI) for a home solar system is simply how long it takes for your energy savings to “pay back” the upfront cost. In everyday terms, your payback period is:
Payback (years) = Total installation cost ÷ Annual energy savings
Simple 3‑Step Scheme
- Find your total cost
Add up panels + inverter + battery (if any) + labor/permits.
Example: £8,000 - Estimate your yearly savings
- Look at last year’s electricity bill (e.g. £1,200)
- Estimate what % solar will cover (e.g. 80 % → £960 saved)
- Look at last year’s electricity bill (e.g. £1,200)
- Divide cost by savings
£8,000 / £960 per year = 8.3 years
Quick‑View Examples
| System Cost | Annual Savings | Payback Period |
| £6,000 | £600 | 10 years |
| £8,000 | £960 | 8 years |
| £10,000 | £1,250 | 8 years |
Tip: If you add a battery, your cost goes up but you’ll save more by using stored power—so your payback might still be in this same 7–10 year range.
After payback, all the electricity your panels produce is essentially free, and you’ll keep saving (and even earn export payments) for many years to come.
