Is solar worth it in Illinois?
A 7.0 kW rooftop system near Chicago produces about 9,159 kWh a year. Priced against the 18 residential tariffs currently on file in Illinois, payback runs from 11 years on the best of them to 96 on the worst.
Why the tariff matters more than the panels
Two households in Illinois with identical roofs and identical systems can see paybacks 11 and 96 years apart, purely because they are on different tariffs. Solar produces at midday; households consume in the evening. Only 55% of what these panels make is used as it is made — the rest is exported, and what an exported kWh earns is set by the tariff and by state net metering rules, not by the hardware.
That is why the figures here are computed hour by hour against each real tariff rather than by taking a bill and assuming solar removes a share of it. How this is modeled →
Payback by tariff in Illinois
7.0 kW system at $3.00/W, household using 1000 kWh a month, no incentives. A range means the export credit is not filed with the tariff and the outcome depends on net metering rules — 18 of 18 tariffs here belong to a utility that reports residential net metering.
| Utility | Tariff | Structure | Annual saving | Payback |
|---|---|---|---|---|
| Ameren Illinois Company | DS-1 Residential Zone 1 | Time-of-use + tiered | $1,068–$1,997 | 11–20y |
| Ameren Illinois Company | DS-1 Residential Zone 2 | Time-of-use + tiered | $1,043–$1,951 | 11–20y |
| Commonwealth Edison Co | RDS - Residential Single Family Without Electric Space Heat Delivery Class | Time-of-use | $1,035–$1,884 | 11–20y |
| Ameren Illinois Company | DS-1 Residential Zone 3 | Time-of-use + tiered | $904–$1,657 | 13–23y |
| Ameren Illinois Company | DS-1 Residential Zone 2 | Time-of-use + tiered | $878–$1,611 | 13–24y |
| Ameren Illinois Company | DS-1 Residential Zone 1 | Time-of-use + tiered | $876–$1,608 | 13–24y |
| Commonwealth Edison Co | BES - Residential Single Family Without Electric Space Heat Delivery Class | Time-of-use | $637–$1,158 | 18–33y |
| Commonwealth Edison Co | BES - Residential Multi Family Without Electric Space Heat Delivery Class | Time-of-use | $566–$1,028 | 20–37y |
| City of Naperville, Illinois (Utility Company) | Residential | Flat | $535–$973 | 22–39y |
| MidAmerican Energy Co | RATE RS - RESIDENTIAL SERVICE | Time-of-use + tiered | $519–$933 | 23–40y |
| MidAmerican Energy Co | RATE RST - RESIDENTIAL TIME-OF-USE SERVICE | Time-of-use | $540–$914 | 23–39y |
| Commonwealth Edison Co | BES - Residential Single Family with Electric Space Heat Delivery Class | Time-of-use | $480–$871 | 24–44y |
| Commonwealth Edison Co | BES - Residential Multi Family With Electric Space Heat Delivery Class | Time-of-use | $477–$866 | 24–44y |
| MidAmerican Energy Co | RATE GE - GENERAL ENERGY SERVICE (Residential) | Time-of-use + tiered | $473–$847 | 25–44y |
| MidAmerican Energy Co | RATE GET - GENERAL ENERGY TIME-OF-USE SERVICE (Residential) | Time-of-use + tiered | $478–$809 | 26–44y |
Price it for your own usage and system size →
What would change this
Your roof. Production is modeled for Chicago on a south-facing array at 20° tilt. Shading, orientation and pitch all move it, and solar resource varies within Illinois itself.
Your usage pattern. A household at home during the day self-consumes more and exports less, which shortens payback wherever export credit is poor.
Rising rates. These figures hold today's prices flat. Electricity prices have been rising, and every rise shortens payback — so treat these as a conservative bound.
State and local incentives. Not included here, and in some states they are worth more than the federal credit was. Check your state energy office before deciding.