Solar panels in St. Clair County, IL
Compare solar costs, payback and local permit rules across 3 St. Clair County towns served by Ameren, then get free, no-obligation quotes.
Free, no-obligation quotes. Savings vary by home and utility. $0-down offers are leases or PPAs and are subject to approval.
Quick answer
Is solar worth it in St. Clair County, IL?
For many homes, yes. With a $150 monthly bill, we estimate a system costs about $10,200 after the Ameren rebate and Illinois Shines in St. Clair County, paying for itself in about 8.1 years on an unshaded, south-facing roof.
How does solar compare across St. Clair County towns?
| Town | Median home value | Owner-occupied |
|---|---|---|
| Belleville | $141,300 | 60% |
| O'Fallon | $295,700 | 70% |
| Swansea | $223,600 | 73% |
Panels across St. Clair County produce about 1,300 kWh per kW a year, so the solar estimate is the same for every town: about $10,200 after incentives and payback in about 8.1 years. What differs is the housing, below.
Estimates for a cash purchase on an unshaded, south-facing roof. Home values and ownership rates are U.S. Census Bureau American Community Survey 5-year estimates; n/a means no Census figure was available. How we estimate
What do St. Clair County towns require for solar?
Permits and zoning rules are set town by town. Highlights from each town's own rules:
- Belleville: Belleville's zoning code has included a solar energy section since 2018. It treats a home system sized mainly to offset the property's own use as an accessory use, with height and size limits for ground-mounted systems.
- O'Fallon: O'Fallon requires a permit for solar panel installations: a building permit if structural changes are proposed, otherwise an electrical permit, handled by the Building and Inspections Division.
- Swansea: Swansea requires a building permit from the village Building and Zoning Department before any residential solar work begins.
Each town page has the full details and sources.
How do I keep solar from raising my St. Clair County property taxes?
File form PTAX-330 with the St. Clair County assessment office. Under Illinois law, a home with solar can be assessed as if it had a conventional energy system, so panels don't raise your assessment.
How does solar work with Ameren in St. Clair County?
Ameren pays about $300 per kW in rebates for new home solar systems with a smart inverter, and since 2025 credits exported power at the supply rate. Power you use as your panels produce it still saves the full retail rate.
See the full Ameren solar guide.
Choosing a company? See how to choose a solar installer in Illinois and what a solar quote should include.
St. Clair County solar FAQ
Which electric utility serves St. Clair County?
The towns we cover in St. Clair County are served by Ameren, which pays about $300 per kW in rebates for new solar systems and credits exported power at the supply rate.
How long does solar take to pay back in St. Clair County?
For an unshaded home with a $150 monthly bill, we estimate payback of about 8.1 years in St. Clair County, after the utility rebate and Illinois Shines.
Will solar raise my property taxes in St. Clair County?
Not if you file form PTAX-330. Illinois lets the county assess a home with solar as if it had a conventional energy system. See how Illinois taxes homes with solar.
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