Solar Panel Calculator for Chicago, IL
Estimate the cost, savings and payback of solar panels in Chicago, IL, using local NREL sunshine data, Illinois prices and electricity rates.
Your result
Enter your numbers and press the button. Your result appears here.
Chicago gets about 4.55 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,319 kWh a year. That ranks #87 of the 111 cities on this site. Output peaks in Jul and is lowest in Dec.
Sunshine in Chicago by month
What an 8 kW system makes in Chicago
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 2.44 | 520 kWh | $100 |
| Feb | 3.37 | 648 kWh | $125 |
| Mar | 4.44 | 920 kWh | $177 |
| Apr | 5.13 | 992 kWh | $191 |
| May | 5.80 | 1,120 kWh | $215 |
| Jun | 6.30 | 1,160 kWh | $223 |
| Jul | 6.67 | 1,240 kWh | $238 |
| Aug | 6.41 | 1,192 kWh | $229 |
| Sep | 5.36 | 992 kWh | $191 |
| Oct | 3.73 | 752 kWh | $145 |
| Nov | 2.79 | 560 kWh | $108 |
| Dec | 2.22 | 472 kWh | $91 |
| Year | 4.55 | 10,552 kWh | $2,029 |
Savings at 19.23¢ per kWh (Illinois average), with every kWh credited at that price.
Cost and payback by system size
At $2.92 per watt, the Illinois average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $11,680 | $1,015 | 11.8 yrs | $12,219 |
| 6 kW | $17,520 | $1,522 | 11.8 yrs | $18,329 |
| 8 kW | $23,360 | $2,029 | 11.8 yrs | $24,439 |
| 10 kW | $29,200 | $2,536 | 11.8 yrs | $30,548 |
| 12 kW | $35,040 | $3,044 | 11.8 yrs | $36,658 |
How many panels you need in Chicago
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 4.55 kW | 12 |
| 750 kWh | 6.82 kW | 18 |
| 1,000 kWh | 9.10 kW | 23 |
| 1,500 kWh | 13.65 kW | 35 |
| 2,000 kWh | 18.20 kW | 46 |
Covering 100% of a year's use at 1,319 kWh per kW.
Common questions
Is solar worth it in Chicago?
At local averages an 8 kW system costs about $23,360 before incentives, saves about $2,029 in its first year and pays back in about 11.8 years.
How many peak sun hours does Chicago get?
About 4.55 a day over the year on a south-facing roof at 20°, from 2.2 in Dec to 6.7 in Jul, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in Chicago?
About 1,319 kWh a year, or 110 kWh a month on average.
Is there a federal solar tax credit?
Not for homeowners who buy their system. The 30% Residential Clean Energy Credit ended for systems installed after December 31, 2025.
Sources
- NREL PVWatts V8 API (south-facing, 20° tilt, 14% losses, typical-year weather): https://developer.nlr.gov/docs/solar/pvwatts/v8/
- EnergySage, Solar panel cost by state (updated November 6, 2026): https://www.energysage.com/local-data/solar-panel-cost/
- U.S. EIA, Electric Power Monthly, Table 5.6.B (residential price, Jan–Aug 2026): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_b