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 It was repealed by Public Law 119-21, and the IRS states the credit is not allowed for expenditures made after December 31, 2025.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 residential state averages published by the U.S. Energy Information Administration in Electric Power Annual Table 2.10, copied verbatim for calendar year 2024 annual average — the most recent complete year EIA has published — and stamped with that period on every state page. Sun hours come from the National Renewable Energy Laboratory solar radiation database. Remaining state and utility incentives are checked against DSIRE. Where a number is an assumption rather than a published rate — panel degradation, the electricity-price escalator, installed cost per watt — every state page prints it in an assumptions block, along with the payback both with and without the escalator, so the figures on the page divide into each other.
Estimate your solar payback
Enter your ZIP and the system size you're considering. The ZIP is used in your browser to identify your state; we then apply that state's average residential electricity rate and annual sun-hour figure to estimate production and break-even years.
Enter a valid US ZIP to see your estimate.
Browse by state
These states have a written analysis: what the utility actually pays for an exported kilowatt-hour, which state credit applies, and the statute, commission order or tariff it comes from. Every other state is a row in the sortable comparison table, which carries the rate, sunlight, modeled payback and recorded incentives for all 51 records.
Read the 2026 guides
- The 2026 federal solar-credit cutoff: an IRS document audit
What Section 25D's 2025 cutoff actually tests, how deposits and unfinished installations are treated, and a worked payback comparison with no phantom 30% credit.
- Net metering in 2026: rebuild the estimate from the actual tariff
Why an EIA state average is not your utility rate, how retail netting differs from net billing, and a worksheet that prices self-consumed and exported solar separately.
- Audit a solar quote with 12 months of utility bills
A document-first worksheet for annual load, avoidable import price, fixed charges, export value, future loads, and the seller's production model.
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 and does not model a battery. It also values all production at the state-average residential price, which is optimistic where exports earn less than retail. Rebuild the final estimate from your actual utility tariff and a self-consumption/export split using the net-metering and 12-month bill-audit guides.
- Do you collect my personal data?
- No personally identifiable information is collected by the calculator. A ZIP code entered on the home form is used in your browser to look up which state you are in, and is not sent to us or stored against any user profile. See the privacy policy for details.