Updated June 2026 · state-average estimates, not financial advice
In Illinois, solar is a long-term play — it pays off, but slowly. The combination of costs and rates stretches the payback to about 13.9 years, so it makes most sense if you value long-term savings, energy independence, or the environmental benefit over a fast financial return.
Illinois solar at a glance
Average electricity rate16.0¢/kWh (above-average)
Peak sun hours4 hrs/day (moderate)
System size (avg home)9.9 kW
Estimated cost (before incentives)$28,222
Federal tax credit (2026)$0 — expired
Estimated payback period13.9 years
Year-1 savings$1,728
25-year net savings$30,688
Estimates for an average home using 10,800 kWh/year, average shading, cash purchase. Data as of 2026.
Among all 51 U.S. states and D.C., Illinois ranks #28 for solar payback (where #1 pays off fastest) — a payback of 13.9 years versus a national median of about 13.5 years. That puts Illinois on the slower half, mainly because of its above-average electricity rates and limited sun.
How much do solar panels cost in Illinois?
For an average Illinois home (about 10,800 kWh/year), a 9.9 kW system costs roughly $28,222 before incentives, based on the U.S. average installed price of about $2.85/watt. Because the 30% federal tax credit expired for 2026 purchases, that gross figure is also your net cost for a cash or loan purchase in Illinois — there's no longer a federal credit to subtract. Your actual price varies with roof size, equipment, and installer, so get at least three local quotes and compare them against the estimate below.
What drives solar payback in Illinois
Two factors decide whether home solar pays off: how much you pay for grid electricity and how much sun your panels get. Illinois has above-average electricity rates (16.0¢/kWh) and moderate sunshine (4 peak sun hours/day). High rates are the single biggest tailwind for solar — every kWh you generate avoids an expensive grid kWh.
The other big change for 2026: the 30% federal residential tax credit (Section 25D) expired for systems placed in service after December 31, 2025. That credit used to knock thousands off the net cost. Without it, cash and loan payback periods are longer than the numbers you'll see on older calculators — which is why the figures above reflect today's reality, not last year's.
Should you buy, finance, or lease in Illinois?
Cash — best lifetime savings (no interest), but you front ~$28,222. Payback ≈ 13.9 years.
Loan — $0–little down, but interest extends payback; works if your rate is low and you'll stay put.
Lease / PPA — $0 down and the installer owns the system (and may still claim a commercial credit through 2027), passing some savings to you. Less lifetime upside, but no upfront cost — often the most sensible option where buying payback is long.
For an average home using about 10,800 kWh/year, a cash solar purchase in Illinois has an estimated payback of 13.9 years, after which the system keeps producing free electricity. Whether that's worthwhile depends on how long you'll stay in the home and how you value non-financial benefits. Note the 30% federal tax credit expired for systems placed in service after Dec 31, 2025.
How much do solar panels cost in Illinois?
At a national-average installed price of about $2.85/watt, a 9.9 kW system sized for an average Illinois home costs roughly $28,222 before any incentives. Your actual quote depends on your roof, equipment, and installer — always get 3+ local bids.
What's the average electricity rate in Illinois?
Illinois residential electricity averages about 16.0¢/kWh (above-average). Higher rates make solar pay off faster, because every kWh you self-generate offsets a more expensive grid kWh.
Estimates only, not financial advice. Figures use state-average data and the assumptions on our methodology. Always confirm with itemized local quotes.