What solar costs in Illinois
Berkeley Lab does not have enough reported installations in Illinois to publish a reliable local price, so the figures below use the national median. Treat them as a starting point, not a quote.
The numbers
High electricity prices make solar pay faster, so a red figure in the third box is good news for a solar buyer and bad news every other month of the year.
Holding a quote above $30,000? Installers in Illinois price the same system very differently. Two more bids is the cheapest way to find out where yours sits.
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What the roof makes month by month in Chicago
A 3.3 to 1 swing across the year, which is steep. A system sized to cover your annual usage will run a large surplus in summer and leave you buying most of your winter power from the grid. Whether that works depends entirely on whether your utility banks the summer surplus for you.
Figures are for an 8 kW array at 20 degrees facing south, modelled from NSRDB radiation data at Chicago.
What different sizes cost in Illinois
| Size | Panels | Price | Output | Year one saving | Payback |
|---|---|---|---|---|---|
| 4 kW | 10 | $15,000 | 4,956 kWh | $953 | 13.8 years |
| 5 kW | 13 | $18,750 | 6,195 kWh | $1,191 | 13.8 years |
| 6 kW | 15 | $22,500 | 7,434 kWh | $1,429 | 13.8 years |
| 7 kW | 18 | $26,250 | 8,673 kWh | $1,667 | 13.8 years |
| 8 kWtypical | 20 | $30,000 | 9,912 kWh | $1,905 | 13.8 years |
| 10 kW | 25 | $37,500 | 12,390 kWh | $2,381 | 13.8 years |
| 12 kW | 30 | $45,000 | 14,868 kWh | $2,858 | 13.8 years |
| 15 kW | 38 | $56,250 | 18,585 kWh | $3,572 | 13.8 years |
| 20 kW | 50 | $75,000 | 24,780 kWh | $4,763 | 13.8 years |
Payback is the same at every size because this table holds the price per watt flat at the national median of $3.75: price and output both grow in step with the system, so their ratio does not change. Real quotes are not quite linear. Permitting, design and connection cost roughly the same on any roof, so a small system usually costs more per watt and a large one less, and pays back correspondingly later or sooner than shown.
Illinois has too few reported installations for a local median, so the price is the national median of what households paid on host-owned systems installed in 2024-2025, compiled by Berkeley Lab. Local quotes can sit well above or below it.
10 programmes in Illinois
The 30% federal credit ended for installations completed after 31 December 2025. These state, utility and local programmes are unaffected by that, and are now the only thing that reduces the price.
| Programme | Type | Run by | Reach | Updated |
|---|---|---|---|---|
| Ameren Illinois Distributed Generation Rebate Program | Rebate Program | Utility | statewide | September 28, 2025 |
| City of Chicago - Solar Zoning Policy | Solar/Wind Access Policy | Local | statewide | September 22, 2023 |
| ComEd - Distributed Generation and Storage Rebates | Rebate Program | Utility | statewide | March 26, 2026 |
| Community Solar Energy Sovereignty Grant Program | Grant Program | State | statewide | March 23, 2026 |
| Illinois Clean Energy Community Foundation Grants | Grant Program | Non-Profit | statewide | October 6, 2022 |
| Illinois Solar and Wind Rights | Solar/Wind Access Policy | State | statewide | September 22, 2023 |
| Illinois Solar for All Program | Solar Renewable Energy Credit Program | State | statewide | August 14, 2024 |
| Interconnection Standards | Interconnection | State | statewide | June 6, 2024 |
| Sales Tax Exemption for Wind, Solar, and Storage - High Impact Business | Sales Tax Incentive | State | statewide | September 12, 2025 |
| Special Assessment for Solar Energy Systems | Property Tax Incentive | State | statewide | March 17, 2025 |
Programme index from DSIRE, N.C. Clean Energy Technology Center, NC State University, licensed CC BY-SA 4.0. “Partial” means it reaches only some utilities or counties. A listed programme can still be closed or out of budget, so check its own page before counting on it.
How Illinois ranks
Closest on payback: Virginia (13.7 yrs), Wisconsin (13.7 yrs), Texas (13.8 yrs), Ohio (13.9 yrs).
Solar in Illinois, answered
How much do solar panels cost in Illinois?
An 8 kW system in Illinois, roughly 20 panels, costs about $30,000 before incentives. That is based on $3.75 per watt, the national median from Lawrence Berkeley National Laboratory for 2024-2025, because too few Illinois installations are reported to publish a local figure. There is no longer a federal tax credit to subtract from that figure.
Is there still a 30% solar tax credit in Illinois?
No. The federal Residential Clean Energy Credit under Internal Revenue Code section 25D was terminated by the One Big Beautiful Bill Act for expenditures made after 31 December 2025, and it did not step down first. A Illinois homeowner buying a system with cash or a loan today receives no federal tax credit. Under a lease or power purchase agreement the credit survives as section 48E but belongs to the company that owns the equipment, not to the household. Illinois still has 10 state, utility or local programmes covering rooftop solar.
How long do solar panels take to pay for themselves in Illinois?
About 13.8 years in Illinois. An 8 kW system costs roughly $30,000 and saves about $1,905 in its first year at the state's average residential rate of 19.22 cents per kilowatt-hour (EIA, July 2026). That calculation includes no federal tax credit, because the residential credit ended after 31 December 2025.
How much electricity does a solar panel produce in Illinois?
Each kilowatt of panels in Illinois produces about 1,239 kilowatt-hours a year, modelled at Chicago facing south at a 20 degree tilt using NSRDB radiation data. An 8 kW system therefore makes roughly 9,912 kilowatt-hours a year. The national average is about 1,332 kilowatt-hours per kilowatt installed.
Is solar worth it in Illinois?
It depends less on sunshine than on your electricity price. In Illinois power costs 19.22 cents per kilowatt-hour (EIA, July 2026), which makes an 8 kW system pay for itself in about 13.8 years and clear roughly $30,923 over 25 years. Solar from your own roof works out at 12.8 cents per kilowatt-hour over its life, against 19.22 cents from the utility.
How many solar panels do I need in Illinois?
A typical Illinois installation is about 20 panels, which is 8 kW at the 400 watt module that is now standard and needs roughly 440 square feet of roof. To size it to your own use, divide your annual kilowatt-hours by 1,239, which is what each kilowatt of panels produces in Illinois each year.
Do solar panels work in winter in Illinois?
Yes, but output falls sharply. In Chicago a kilowatt of panels makes about 148 kilowatt-hours in Jul and about 45 in Dec, a swing of 3.3 to 1 across the year. A system sized to cover your annual consumption will therefore run a surplus in summer and leave you buying power in winter, so how your utility settles that difference matters as much as the size of the array.
Three competing quotes beat any amount of comparing panel brands
Sales cost and margin are over a third of an installed price in Illinois, and they are the part that competition removes. A single quote from whoever reached you first is how people end up in the top quarter of what their neighbours paid.
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Prices and rules change. We will tell you when they do
Berkeley Lab publishes installed prices once a year, the EIA updates electricity rates every month, and Congress changed the tax treatment of all of this in 2025. One email when something on this site actually changes, and nothing else.
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