Solar Panel Payback Calculator
Annual generation × tariff = yearly savings; cost ÷ savings = payback. With degradation and rate inflation as honest optional tweaks.
Quick answer: Estimate how many years a rooftop solar system takes to pay for itself: system size, cost, sun hours and your electricity rate in, break-even years and 25-year savings out. Free and private.
Sanity-check quotes with this — real yield depends on roof angle, shade and climate.
How to use
- Enter installed cost and system size from any quote.
- Set your peak sun hours (4–6 typical) and electricity rate.
- Read payback years and projected 25-year savings; tweak inflation to stress-test the quote.
About this tool
Rooftop yield ≈ system kW × peak sun hours × 365 × 0.80 performance ratio. Yearly saving = yield × tariff (plus exported surplus where net-metering applies). Payback = installed cost ÷ saving; 25-year net saving compounds with a modest annual tariff-inflation assumption you control. Quotes vary wildly by roof and region — treat this as a sanity check against salesperson numbers, which is exactly what it's for.