All states / Illinois
Solar in Illinois
At 19.22¢ per kWh and 1308 kWh of production per kW each year, a household paying $200 a month needs a 8.97 kW system. Paid in cash, it returns its $26,742 cost in 8.5 yr.
Two prices, two answers
Payback 8.5 yr — at competitive quoted prices ($2.98/W, EnergySage 2026): net cost $26,742, 25-year net $31,510.
LBNL 2023: fewer than 20 observations, so LBNL publishes no median for this state. We show one basis here rather than borrow a neighbouring state's.
Where a second basis exists, the gap between the two is methodology, not staleness: quoted prices are what you get if you shop around for competitive quotes; reported prices are what the average buyer actually paid, as recorded in permit and incentive data. Every table below uses quoted prices. Why we show both.
By monthly bill
| Your bill | Use / yr | System | Panels | Net cost | Payback | 25-yr net (cash) | Lease, year 1 |
|---|---|---|---|---|---|---|---|
| $100/mo | 5,494 kWh | 4.2 kW | 11 | $12,518 | 9.4 yr | $11,797 | −$6 |
| $150/mo | 8,616 kWh | 6.59 kW | 17 | $19,630 | 8.7 yr | $21,651 | −$10 |
| $200/mo | 11,738 kWh | 8.97 kW | 23 | $26,742 | 8.5 yr | $31,510 | −$13 |
| $300/mo | 17,981 kWh | 13.75 kW | 35 | $40,967 | 8.2 yr | $51,218 | −$21 |
Cash, loan or lease — at $200 a month
| How you pay | 25-year net | Upfront | Year 1 | Payback / cash flow | Federal credit to you |
|---|---|---|---|---|---|
| Cash incl. $13,734 from Illinois Shines REC contract, $6,867 of it at switch-on | $31,510 | $26,742 | $2,560 | 8.5 yr | $0 |
| Loan $207/mo · 6.99% APR · 20 yr incl. $13,734 from Illinois Shines REC contract, $6,867 of it at switch-on | $8,531 | $0 | $74 | cash-flow neutral from year 1 (+$74/yr) | $0 |
| Lease / PPA | −$3,078 | $0 | −$13 | never | $0 |
The 30% federal credit goes to the system owner, not to you. It is reflected in the rate you are offered. The owner claims it at 30% under IRC 48E.
The inputs, and where they came from
| Input | Value | Source |
|---|---|---|
| Residential electricity rate | 19.22¢/kWh | U.S. EIA API v2, electricity/retail-sales, residential sector, 2026-07 |
| Specific yield | 1308 kWh/kW/yr | NLR (formerly NREL) PVWatts v8 API, 1 kW reference system (city:chicago-il) |
| Installed cost | $2.98/W | EnergySage Marketplace real-quote average, as of Sep 2026; page updated 2026-08-28 |
| Export compensation | net billing, export credited below retail · 49% | Retail-rate net metering closed to new customers after 31 December 2024 under Public Act 102-0662. The Illinois Power Agency states that full retail rate net metering is no longer available and that new customers receive only energy supply credits for the excess energy they send back to the grid. Energy generated and used on site is still worth the full retail rate; only exports are credited at the supply rate. Customers interconnected before the cut-off keep retail-rate netting. ComEd's published supply price to compare was about 9.66 c/kWh through May 2026, rising to about 10.399 c/kWh for summer 2026, against an Illinois residential retail rate of 19.89 c/kWh (EIA 2026-06): 0.49 to 0.52. The record uses the lower figure, 0.49. The supply price is set each June and this ratio moves with it. Follows: Commonwealth Edison (the state's largest electric utility). Ameren Illinois changed on the same date; MidAmerican from 1 January 2025. Source, read 2026-09-05. |
| Federal credit, purchase | 0% | IRC 25D (expired) |
| Federal credit, third-party owner | 30% | IRC 48E (Clean Electricity Investment Credit) |
| State incentives | $0 | No upfront statewide credit or rebate for a typical owner-occupier (verified) · Not modelled: Illinois Shines REC contract, Small Distributed Generation 0-10 kW AC |
City-level production on file for: Chicago. The figures above use Chicago.