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Solar payback: test your own quote

Payback is the installed price divided by what the panels are worth to you each year. That yearly value depends less on the panels than on how much of their electricity you use yourself.

Updated 2 October 2026 · energy.org.uk editorial team

The short answer

Yearly value = (electricity you use from the panels × your unit rate) + (electricity you export × your export rate). Divide your quote by that figure for a simple payback in years. The solar calculator does this with your roof, use and quote, and shows a range.

Why the answer is a range

  • Time at home. Electricity you use yourself saves your full unit rate; exported electricity earns a lower export rate. A home that is occupied in the day uses more directly, so its payback is faster.
  • Your export tariff. Rates vary between suppliers and some need you to buy electricity from them. See compare export tariffs.
  • Future prices. If electricity prices rise, solar is worth more; if they fall, less. The simple calculation assumes today's prices.

Check

What to check first

  • The quote is for panels only, or the battery is priced separately. A battery has its own payback; see the solar battery calculator.
  • Your annual electricity use from your bill, rather than a typical figure.
  • Your roof's direction and shading, which change generation.
  • The export rate you can actually get, including any conditions.

Do

Practical next steps

  1. Enter your postcode, roof and use in the solar calculator.
  2. Add the installed price under "Make this more accurate" to see the payback range.
  3. Compare several quotes in the solar quote checker.
  4. Shift some use into daylight hours, such as timed laundry, to use more of your own electricity.

Take care

Important limitations

  • The calculation leaves out maintenance, a likely inverter replacement during the system's life, and any finance costs.
  • Generation estimates use long-term average sunshine; individual years vary.
  • If there is no payback at current prices, the calculator says so rather than showing a long number.

Related tools and guides

Sources

Official sources checked 2 October 2026.