Enter the cost of a solar PV system, how much it generates a year, and roughly how much of that you use yourself rather than export. This estimates the yearly saving and how many years the system takes to pay for itself.
Solar pays back in two ways: every unit you use yourself saves you the full electricity rate, and every unit you export earns a smaller payment under the Smart Export Guarantee. The single biggest lever is how much you use yourself, which is why batteries, timers and daytime usage shift the maths. A typical home system costs a few thousand pounds, generates 3,000 to 4,000 kWh a year, and pays back in roughly 8 to 12 years, then runs at a profit. For the wider picture see is solar worth it and solar battery storage.
Common questions
How long do solar panels take to pay back?
For most UK homes, roughly 8 to 12 years, depending on the system cost, how much you generate and how much you use yourself rather than export. After that the electricity is effectively free for the panels' remaining life.
Do solar panels still save money after payback?
Yes. Panels usually last 25 years or more, so once they have paid for themselves, every year of generation after that is a saving. The 25-year figure shows the long-run total.
What makes solar pay back faster?
Using more of your own generation rather than exporting it. Self-used energy saves the full electricity rate, around 26p, while exported energy earns only the export rate, around 15p or less.