Delaware vs Illinois Solar Comparison
Delaware gets more sun (4.2 hrs/day) while Illinois has the faster payback (9 years).Illinois offers higher 20-year savings at $32,600.
Delaware
4.2 hrs
9.8yr payback
$30,200
20yr savings
Illinois
4.0 hrs
9yr payback
$32,600
20yr savings
Side-by-Side Comparison
| Metric | Delaware | Illinois |
|---|---|---|
| Peak Sun Hours | 4.2 hrs | 4.0 hrs |
| Cost per Watt | $3.00 | $3.15 |
| 6kW System Cost | $18,000 | $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 | 14.94¢/kWh | 16.27¢/kWh |
| Payback Period | 9.8 years | 9 years |
| 20-Year Savings | $30,200 | $32,600 |
Verdict
Illinois is the better state for solar ROI with $32,600 in 20-year savings and a 9-year payback period. Delaware has more sun exposure at 4.2 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 Delaware or Illinois?
Delaware gets more sun (4.2 peak hours/day vs 4). Illinois has a faster payback (9 years) and Illinois offers higher 20-year savings ($32,600).
How do solar costs compare between Delaware and Illinois?
A 6kW system costs $18,000 in Delaware 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