Solar Payback Calculator

Most solar calculators still subtract a tax credit you can no longer claim

The 30% federal residential credit ended for anything installed after December 31, 2025. Quotes and calculators built before that still take 30% off the top — which can make a system look thousands of dollars cheaper, and years faster to pay back, than it really is. This one does the arithmetic without it.

Check this before you trust any solar number, including ours

A $30,000 system used to carry a $9,000 federal credit. For an installation finished in 2026, that $9,000 is gone. If a quote, a calculator, or a salesperson still shows it, the payback period you are being sold is wrong — and the error runs in the seller's favour, not yours.

Do not take our word for it. The credit is Section 25D of the tax code. It was repealed by Public Law 119-21, and the IRS states the credit is not allowed for expenditures made after December 31, 2025. One detail catches people out: the IRS treats the expenditure as made when installation is completed, so a 2025 deposit or signed contract does not qualify if the crew finished the job in 2026. Unused credit from a system completed in 2025 or earlier can still be carried forward.

Tax rules verified against IRS and Congressional Research Service publications on 2026-08-13. We are not tax advisers — confirm your own situation with one.

Where the numbers come from

Electricity rates are the state residential averages published monthly by the U.S. Energy Information Administration. Sun hours come from the National Renewable Energy Laboratory solar radiation database, and the ZIP-level view calls NREL's PVWatts model directly for your nearest weather station rather than reusing a state average. Remaining state and utility incentives are checked against DSIRE. Every figure on a state page is dated, and where a number is an assumption rather than a published rate — degradation, rate inflation, installed cost per watt — it says so on the page instead of hiding inside the maths.

Estimate your solar payback

Enter your ZIP and the system size you're considering. We'll pull your state's average residential electricity rate and an annual sun-hour figure to estimate production and break-even years.

Enter a valid US ZIP to see your estimate.

Estimate only. Numbers shown are modeled projections, not quotes or guarantees. Actual production, electricity rates, financing terms, and available incentives vary by household, utility, roof condition, shading, and policy changes. The Residential Clean Energy Credit (Section 25D, the 30% federal tax credit) expired for systems placed in service after December 31, 2025. Verify all numbers with a licensed installer and your utility before making a purchase decision. See full disclaimer.

Browse by state

Each state page shows the average residential electricity rate, sun-hour range, and remaining state-level incentives in plain English.

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Read the 2026 guides

Frequently asked questions

Did the federal solar tax credit really expire?
Yes. The 30% federal residential solar tax credit under Internal Revenue Code Section 25D sunset on December 31, 2025. Systems placed in service in 2026 and later do not receive the 30% federal credit. State and utility incentives may still apply — see the per-state pages.
How does the payback estimate work?
The calculator multiplies your system size (kW) by your state's average peak sun hours per day (from NREL) to estimate annual kWh produced, then values that production at your state's average residential electricity rate (from the EIA). Payback equals installed cost divided by annual savings, adjusted for panel degradation and assumed rate inflation.
Is this a quote or financial advice?
No. This is an educational estimator using public EIA and NREL data. Your actual payback depends on installer pricing, roof orientation and shading, your specific utility rate plan and net metering terms, panel degradation, and battery storage choices. Get at least three local quotes before making a financial decision.
Does this calculator capture battery storage and net metering?
The base calculator estimates panel-only payback. Battery storage payback and net metering structure (full retail, net billing, avoided cost, or none) vary by state and utility — see the dedicated guides for battery payback math and the state-by-state net metering map.
Do you collect my personal data?
No personally identifiable information is collected by the calculator. ZIP codes entered on the home form are processed in your browser. The ZIP drill-down page sends the ZIP server-side to the NREL PVWatts API to model production for your nearest weather station; the ZIP is not stored against any user profile. See the privacy policy for details.