California vs Illinois Solar Comparison
California gets more sun (5.8 hrs/day) while California has the faster payback (5.5 years).California offers higher 20-year savings at $58,200.
California
5.8 hrs
5.5yr payback
$58,200
20yr savings
Illinois
4.0 hrs
9yr payback
$32,600
20yr savings
Side-by-Side Comparison
| Metric | California | Illinois |
|---|---|---|
| Peak Sun Hours | 5.8 hrs | 4.0 hrs |
| Cost per Watt | $3.30 | $3.15 |
| 6kW System Cost | $19,800 | $18,900 |
| Federal Tax Credit | 30% | 30% |
| State Tax Credit | None | None |
| State Rebate | None | None |
| Net Metering | Full Net Metering | Full Net Metering |
| Electricity Rate | 31.22¢/kWh | 16.27¢/kWh |
| Payback Period | 5.5 years | 9 years |
| 20-Year Savings | $58,200 | $32,600 |
Verdict
California is the better state for solar ROI with $58,200 in 20-year savings and a 5.5-year payback period. California has more sun exposure at 5.8 hrs/day, making it ideal for maximum energy production. Both states qualify for the 30% federal solar tax credit.
Frequently Asked Questions
Is solar better in California or Illinois?
California gets more sun (5.8 peak hours/day vs 4). California has a faster payback (5.5 years) and California offers higher 20-year savings ($58,200).
How do solar costs compare between California and Illinois?
A 6kW system costs $19,800 in California vs $18,900 in Illinois before incentives. Both qualify for the 30% federal tax credit.
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Data verified March 2026 · Source: NREL, DSIRE, EIA