Calculate how long a solar system takes to repay its cost through bill savings.
Simple payback divides the up-front cost by the recurring annual benefit to get the number of years before the solar system has paid for itself. Everything after that point is net gain, which the lifetime figures make explicit. Payback is the first screen most buyers apply: a system that pays back inside its warranty period is a very different proposition from one that does not.
Solar Payback
Payback (years) = Installed cost after any grant ÷ annual annual bill saving
Payback (years) = Installed cost after any grant ÷ annual annual bill saving Simple payback divides the up-front cost by the recurring annual benefit to get the number of years before the solar system has paid for itself. Everything after that point is net gain, which the lifetime figures make explicit.
Payback is the first screen most buyers apply: a system that pays back inside its warranty period is a very different proposition from one that does not.
This calculator takes 3 inputs: Installed cost after any grant, Annual bill saving, Expected life. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.