Typical solar cost and payback in La Grange Park.

The net out-of-pocket and payback figures above use the local production, utility, and incentive assumptions; the methodology and source links are documented in the worth-it diagnostic.

How big a system fits a La Grange Park home?

A 7 kW system is the median residential size in Cook County and the baseline NREL’s PVWatts model uses. At the 60526 coordinates, a south-facing array at 20° tilt produces 9,400 kWh/year. The Cook County average residential bill is $137/mo, which a 7 kW array offsets a meaningful share of for a south-facing roof. East or west orientation drops annual production by 10 to 20%; predominantly north-facing roofs rarely pencil. Households with above-average usage ($150+ monthly bills, EV in the driveway, heat pump on the way) often size up to 8 to 10 kW; under-$80-monthly households are usually below the sizing floor where payback works.

Gross install cost

Residential turnkey installs in Illinois currently price at roughly $2.80 to $3.40 per watt for a typical 6 to 8 kW system, consistent with NREL’s residential PV benchmark and the Lawrence Berkeley National Laboratory Tracking the Sun annual installed-price reporting. At 7 kW, that translates to a gross install range of roughly $19,600 to $23,800 before any incentives. “All-in” price ranges typically include the panels, inverter, racking, permitting, and labor, but should be verified against the specific proposal. Quotes outside this band, particularly above it without a clear reason (battery storage, complex roof, major service panel upgrade) warrant a second opinion.

After incentives

The federal Section 25D Residential Clean Energy Credit expired December 31, 2025 under Public Law 119-21, so 2026 cash and loan installs do not receive a 30% federal credit. Summit’s page on the federal credit in 2026 explains the change and what Section 48E still covers for third-party-owned systems.

Illinois Shines compensates residential systems for their renewable-energy credits, with payment terms set by Illinois Power Agency. The exact REC value varies with the active program block or contract terms; current values are published by the Illinois Shines program . Smart Inverter Rebate (ComEd) / Distributed Generation Rebate (Ameren) also applies for qualifying residential systems: $300/kW, approximately $2,100 for a typical 7 kW residential system. The rebate amount and eligibility rules move with each ICC tariff cycle or program year.

For the La Grange Park reference system, the combined Illinois Shines value and Smart Inverter Rebate (ComEd) / Distributed Generation Rebate (Ameren) bring net cash out-of-pocket to roughly ~$9,100 on a $19,600 to $23,800 gross install. The full math is documented on the worth-it page.

Payback range

Cash payback at current Commonwealth Edison rates and the reference system specs lands at 7 to 8 years. Financed payback runs longer, at 12 to 15 years, once dealer fees (typically 10 to 30% per the CFPB August 2024 issue spotlight) and interest layer in. The difference between the two is mostly the dealer fee, not the interest. Asking for the cash $/W alongside any financed proposal is the single most effective tool a homeowner has at the quote stage; the gap is the markup.

Assumptions and limits

• Production estimates trace to NREL’s PVWatts v8 model at the La Grange Park ZIP. Real installs vary with the actual roof plane, shade pattern, and equipment.
• Utility rate basis is Commonwealth Edison’s current residential tariff filed with the Illinois Commerce Commission. Supply and delivery rates reset on the utility's filing schedule, so the figures here should be re-verified against the current ICC filings before treating any number as fixed.
• This page does not model battery storage, electric vehicle load offset, or future rate-case-driven changes to the supply rate. Each of those moves the payback figure, sometimes substantially. A real proposal should call them out explicitly.