Is solar worth it in Illinois?

Illinois gets moderate sunshine — about 4 peak sun hours a day — and residential electricity runs around $0.16/kWh. For a typical $150-a-month power bill, that points to roughly a 9.6-kW system costing about $28,896 — with no federal tax credit, which ended for installations completed after December 31, 2025 — paying for itself in about 16.1 years and netting on the order of $32,469 over 25 years. Your own numbers will differ — the calculator above uses your real bill.

Illinois pairs modest sun with a strong state incentive (Illinois Shines / SREC program) that can meaningfully cut net cost. With the federal credit gone, that state incentive is now the main thing making payback better than the sunshine alone would suggest.

What changes the math in Illinois

• Your electricity rate — the more you pay per kWh, the more each solar kWh saves you. Illinois sits at about $0.16.
• Sun hours — more sun means a smaller, cheaper system covers the same usage. Illinois averages ~4 hours.
• Net metering / buyback — how your utility credits power you export swings the payback; check your specific utility's current terms.
• Install cost — quotes vary by installer and roof; the calculator defaults to a typical $/watt you can override.

Illinois: the rules that actually decide your payback

Who your utility is, and why it matters

ComEd serves the Chicago metro and the north; Ameren Illinois serves the rest. Both operate under the state's adjust-style framework: net metering credits are combined with the Illinois Shines smart-inverter rebate and the state's renewable-energy credit market into one integrated package.

What your exported power is worth

Illinois transitioned from full-retail-rate net metering to a supply-rate credit plus rebate model. Exports credit against the supply portion of your bill, not the full retail rate — and the $300/kW smart-inverter rebate (about $1,800 on a typical 6 kW system) is paid upfront to offset the difference. Ameren customers can choose from five rate structures as of June 2026; which one you are on changes the arithmetic.

The Illinois incentive layer

The smart-inverter rebate is the headline — $300 per kW for a system with a qualifying inverter, and $300-450 per kWh for paired storage depending on utility. On top of that, Illinois Shines' SREC-style payments (administered through approved vendors) provide a fifteen-year production-income stream. The combination is among the richest state packages in the country, and it is what makes Illinois solar pencil despite middling sun.

Battery and self-consumption

Storage rebates of $300/kWh (Ameren standalone or paired) or $450/kWh (ComEd paired) knock a third to nearly half off a battery's cost before any energy value is counted. With exports already crediting against supply rates, the rebate is the reason to include storage in an Illinois quote rather than the arbitrage math.

What to check on a Illinois quote

• Confirm the smart-inverter rebate is applied as an upfront payment or a system-cost reduction — not assumed as future income in the payback model, which changes the financing picture.
• Ask which of the five Ameren rate options (or the ComEd equivalent) the savings model uses, and whether it matches your actual current tariff.
• Ask whether the Illinois Shines SREC payments are included, at what price per kWh, and for how many years — and whether the installer is the approved vendor of record.
• If storage is quoted, verify the correct rebate tier: $300/kWh standalone, $300/kWh Ameren-paired, or $450/kWh ComEd-paired.

Programme and tariff detail above is summarised from Illinois Shines (Adjustable Block Program), Illinois Power Agency. Last reviewed 20 August 2026 by SolarDime editorial. These rules change — confirm the current terms with your utility and the regulator before you sign.