Are Solar Panels Worth It in Illinois? 2026 Cost & Payback
A typical Illinois household uses about 750 kWh a month and pays 19.06¢ per kWh — roughly $143 a month. Covering that takes a 6.5 kW system costing about $20,026, which pays for itself in about 10 yr 7 mo.
Solar payback calculator — Illinois
Adjust any input to see how the payback period moves.
Pays for itself in
10 yr 7 mo
from switch-on
25-year net gain
$34,844
after paying it off
System size
6.5 kW
Up-front cost
$20,032
Year 1 savings
$1,716
Year 1 output
9,003 kWh
No federal tax credit applied. The 30% residential credit (IRC §25D) ended for purchases made after 31 December 2025. Leases and PPAs fall under a different provision claimed by the installer.
The numbers behind it
| Average electricity rate | 19.06¢ / kWh |
|---|---|
| Peak sun hours per day | 4.69 hours |
| Annual yield per kW installed | 1,392 kWh |
| Typical monthly usage | 750 kWh |
| System size needed | 6.5 kW |
| Installed cost per watt | $3.10 |
| Gross system cost | $20,026 |
| Federal tax credit | Not available (expired for 2026 purchases) |
| Net up-front cost | $20,026 |
| First-year output | 9,000 kWh |
| First-year savings | $1,715 |
| Net metering | Full retail net metering |
| Payback period | 10 yr 7 mo |
| 25-year net gain | $34,831 |
Net metering in Illinois
Illinois credits every exported kilowatt-hour at the full retail rate, so the grid effectively acts as a free battery. This is the most favourable arrangement and shortens payback considerably.
Common questions
How much do solar panels cost in Illinois?
At around $3.10 per watt installed, the 6.5 kW system a typical Illinois home needs works out to roughly $20,026 before any incentives. The 30% federal residential credit no longer applies to systems purchased after 31 December 2025, so that is also the net price.
How long do solar panels take to pay for themselves in Illinois?
About 10 yr 7 mo. That accounts for panel output falling roughly 0.5% a year and utility rates rising around 2.5% a year, which pull the answer in opposite directions.
Does Illinois have net metering?
Illinois credits every exported kilowatt-hour at the full retail rate, so the grid effectively acts as a free battery. This is the most favourable arrangement and shortens payback considerably.
How much will I save over 25 years in Illinois?
Roughly $34,831 after the system has paid for itself — about 174% return on the up-front cost. Savings are larger if electricity prices rise faster than 2.5% a year.
Is Illinois sunny enough for solar?
Illinois averages about 4.69 peak sun hours a day, and a well-oriented array there yields roughly 1,392 kWh per kW installed each year. Sunlight matters less than most people assume — electricity price is the bigger driver, which is why cloudy, expensive states often beat sunny, cheap ones.
How we calculate this
We model 25 years one year at a time rather than dividing cost by first-year savings. Panel output falls 0.5% each year and electricity prices rise 2.5% each year, so the payback figure reflects both.
Production uses the modelled AC yield for Illinois rather than a flat efficiency factor. A peak-sun-hours approximation runs about 9% high, which is enough to make payback look a year faster than it is.
We assume 40% of generation is used in the home as it is produced, with the rest exported and credited according to the state's net metering rules.
Data vintage: Electricity: EIA Electric Power Monthly Table 5.6.B (residential, May 2026 YTD). Solar resource: PVGIS v5.3 (EU JRC), ERA5 2005-2023. Gasoline: AAA state averages. Natural gas: EIA residential by state. Heating degree days: NOAA CPC population-weighted normals. Retrieved 2026-08-03/04. Install costs, household usage, net-metering status, annual mileage, time-of-use spreads and outage hours remain estimates.