Solar Panel Payback Calculator
Work out how many years it takes for a home solar system to pay for itself, what it costs after incentives, and a simplified 25-year cash scenario. Everything runs in your browser — nothing is sent anywhere and no email is required.
All defaults are illustrative. Production factor, annual degradation, utility-price changes and self-use are your assumptions; this is not the PVWatts model. Incentives default to zero for new 2026 projects. Excludes financing, replacements and discounting.
How the math works
This simplified annual-energy model uses your entered production factor:
kWh/year = system kW × peak sun hours × 365 × production factor
Electricity used at home is valued at your retail rate; exports use your separate export rate. Annual maintenance is deducted. Production declines by your degradation assumption and retail rates change by your escalation input; the export rate stays fixed. Payback is the first modeled point when cumulative net savings reach initial net cost.
Frequently asked questions
What payback should I expect?
There is no universal payback period. Enter a real installed quote, confirmed incentives, local production expectations and your utility's self-use and export value. Compare the result with the time you plan to own the system.
Is a 30% federal credit available for a new 2026 installation?
The IRS states that the Residential Clean Energy Credit is unavailable for property placed in service after December 31, 2025. This calculator defaults incentives to zero. Enter only confirmed applicable incentives as an equivalent percentage of the installed price; do not simply add overlapping program percentages.
What are peak sun hours?
Peak sun hours express daily solar irradiation as equivalent hours at 1,000 watts per square meter. They are not daylight hours. Use location- and orientation-specific production modeling such as PVWatts for a more detailed estimate.
Is the 25-year result an investment return?
It is an undiscounted scenario of electricity value minus entered maintenance and initial net cost. Financing, tax effects, roof work, equipment replacements and changing export rules are not modeled. It is not a rate of return.
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