Solar Panel Payback Calculator

How to use

1. Enter installed cost and system size from any quote.
2. Set your peak sun hours (4–6 typical) and electricity rate.
3. 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.

FAQ

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