Solar Payback Period in Illinois
Estimated payback, savings, and ROI for a residential solar system in Illinois — updated for 2026
Urgent tax credit deadlines
- Section 30D EV credit (up to $7,500) — expires June 30, 2026 (12 days left).
- Section 48E solar ITC safe harbor — construction must start by July 4, 2026 (16 days left).
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Solar ROI Overview for Illinois
Based on Illinois's average of 4.3 peak sun hours per day and utility rates of $0.160/kWh, a typical 7kW residential solar system in Illinois would:
- Cost approximately $21,700 before incentives
- Generate about 8,460 kWh/year
- Save you $1,354/year ($113/month)
- Pay for itself in 16 years
- Deliver a 56% ROI over 25 years
Illinois has solid solar potential with sun hours near the national average. Combined with local utility rates, solar remains a worthwhile investment in Illinois.
Payback by System Size in Illinois
| System Size | Cost | Production | Annual Savings | Payback | 25yr ROI |
|---|---|---|---|---|---|
| 4 kW | $12,400 | 4,834 kWh | $773 | 16 yrs | 56% |
| 5 kW | $15,500 | 6,043 kWh | $967 | 16 yrs | 56% |
| 6 kW | $18,600 | 7,251 kWh | $1,160 | 16 yrs | 56% |
| 7 kW | $21,700 | 8,460 kWh | $1,354 | 16 yrs | 56% |
| 8 kW | $24,800 | 9,668 kWh | $1,547 | 16 yrs | 56% |
| 10 kW | $31,000 | 12,085 kWh | $1,934 | 16 yrs | 56% |
How Solar Payback Works in Illinois
Solar payback period is the time it takes for your cumulative electricity savings to equal the total cost of your solar system. In Illinois, the calculation depends on three key factors:
- System cost — $3.10/Watt average in Illinois
- Electricity rate — $0.160/kWh average utility rate
- Solar production — 4.3 average peak sun hours/day
After the payback period of 16 years, your solar panels continue generating free electricity for 15-20+ more years. With utility rates historically increasing 2-4% annually, your actual savings will likely exceed these estimates.
Illinois Solar Data Summary
- Average Cost/Watt
- $3.10
- Average Utility Rate
- $0.160/kWh
- Peak Sun Hours
- 4.3 hrs/day
- Data Coverage
- 10 ZIP codes
Related Tools for Illinois
Compare with Fastest Payback States
| State | Payback | Annual Savings | 25yr ROI |
|---|---|---|---|
| Illinois (you) | 16 yrs | $1,354 | 56% |
| Louisiana | 11.8 yrs | $1,537 | 111% |
| South Dakota | 13.5 yrs | $1,452 | 85% |
| West Virginia | 13.7 yrs | $1,433 | 83% |
| Minnesota | 13.8 yrs | $1,574 | 81% |
| Kentucky | 13.9 yrs | $1,359 | 80% |
📖 Complete Guide to Solar ROI
Want to understand every factor that affects your solar payback period? Read our comprehensive guide covering financing options, NEM policies, and how to maximize your returns.
Read: Complete Guide to Solar ROI in 2026 →