Solar panels in Illinois
Roofs across Illinois get about 1,493 hours of usable sunlight a year, and electricity costs 16.3¢/kWh. That combination puts a typical system's payback at 9.9 years. Here's the detail, from real rooftop data across 4 Illinois cities.
Check your own roof in Illinois → These are regional figures; your roof's size, pitch and shading move them a lot.
How Illinois compares
Illinois gets more sunlight than 44% of the cities we measure, and its electricity costs more than 64% of states and provinces. Both matter, but not equally: the electricity rate usually matters more, because solar saves money by replacing power you would otherwise buy. A sunny state with cheap power often pays back slower than a cloudy state with expensive power. Why that happens →
Solar by city in Illinois
| City | Sun hrs/yr | Panels | Net cost | Payback |
|---|---|---|---|---|
| Naperville | 1,555 | 21 | $16,758 | 9.5 yrs |
| Aurora | 1,493 | 22 | $17,556 | 9.9 yrs |
| Chicago | 1,469 | 22 | $17,556 | 9.9 yrs |
| Rockford | 1,453 | 22 | $17,556 | 10 yrs |
What a system costs in Illinois
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 4,061 | $6,384 | $662 | 9.6 yrs |
| 12 panels | 4.8 kW | 6,091 | $9,576 | $993 | 9.6 yrs |
| 16 panels | 6.4 kW | 8,122 | $12,768 | $1,324 | 9.6 yrs |
| 20 panels | 8 kW | 10,152 | $15,960 | $1,655 | 9.6 yrs |
| 26 panels | 10.4 kW | 13,198 | $20,748 | $1,858 | 11.2 yrs |
Payback stops improving as systems grow, then gets worse. You can only save on electricity you were going to buy, so once a system covers your usage the extra panels mostly export at a lower rate.
Illinois solar incentives
Every US household can claim the 30% federal residential clean energy credit, which is what the "after credit" figures above assume. On a $25,080 system that is $7,524 back. How the credit works →
State, utility and municipal incentives stack on top and change often — Illinois may offer rebates, property or sales tax exemptions, or performance payments. We deliberately don't list specific state programmes here because they change several times a year and stale numbers are worse than none. The DSIRE database is the standard reference and is kept current.
Illinois solar questions
Is solar worth it in Illinois?
At 16.3¢/kWh and 1,493 usable sun hours, a typical system pays back in about 9.9 years and returns roughly $26,829 over 25 years. That is a solid return.
How many solar panels do I need in Illinois?
About 22 panels for a home using 10,800 kWh a year. Each 400W panel produces roughly 508 kWh annually at Illinois sunlight levels.
How much do solar panels cost in Illinois?
A 8.8 kW system runs about $25,080 before incentives and $17,556 after the 30% federal credit. Quotes vary widely by installer and roof complexity — get three.
Worth reading before you buy
Regional estimates generated 2026-08-22 from Google Solar API rooftop samples across 4 Illinois cities, and average Illinois electricity rates. Not a quote and not financial or tax advice.