Solar Panels in Joliet, IL: 2026 Cost, ComEd Net Metering & Savings

Joliet and the bill

Joliet is ComEd. Ameren territory is farther downstate. Do not mix the disclosure forms. Joliet has a ComEd bill and a housing stock of older brick houses and newer southwest-suburban roofs. The sun figure matches Chicago. Trees are less continuous than on the North Side. Supply-only net metering is the default assumption for a new residential interconnection. A bid that still shows full retail credit for every exported kilowatt-hour needs the tariff section that says so. The 2025 EIA residential average for Illinois was 17.67 cents per kWh. That statewide figure is what our calculator uses. It is not the ComEd tariff. A rounded solar resource for this metro is about 4.2 peak sun hours a day.

Export credits and any SREC or REC

ComEd is the usual utility for Joliet. New residential ComEd customers are on supply-only net metering: energy you import can be netted against supply, and delivery charges still apply to grid electricity. Illinois Shines is separate. For the program year starting June 1, 2026, distributed generation up to 10 kW in ComEd territory (Group B) is priced at about $80.77 per REC. Projects approved on or after that date get 50 percent of the REC payment at energization and the remainder over six years. You see the money only to the extent the approved vendor's disclosure passes it through. This is not an eligibility finding.

Roofs, climate, permits, and HOAs

Detached houses are the usual candidate. Some older services are small. Ask about a panel upgrade before it becomes a change order. A Joliet permit comes from the local building department, not from ComEd. An HOA can add its own review. This page does not quote a IL permit fee or an approval, because both depend on the address. Use ComEd's current rider and the Illinois Shines disclosure if that incentive is claimed. Ignore an Ameren downstate sheet.

Estimated cost range

Estimated cost range for Joliet, labeled as an estimate and not a local quote: Berkeley Lab's August 2026 update put 2025 host-owned residential systems at about $3.60 per watt before incentives, about $3.00 per watt in the cash subset, and about $4.50 per watt in the loan subset. The median size in that set was 7.7 kW. Joliet is about 4.2 peak sun hours a day, against about 4.2 statewide. The federal residential credit under 26 U.S.C. § 25D ended for systems placed in service after December 31, 2025. The IRS treats that expenditure as made when the original installation is completed.

• Cash

  $3.00/W

  $23,100

  Subset classified as cash

• Middle published case

  $3.60/W

  $27,720

  All host-owned systems

• Loan

  $4.50/W

  $34,650

  Financed subset, before interest

Before incentives. A loan price here excludes interest. The federal residential credit under section 25D ended for systems placed in service after December 31, 2025. Berkeley Lab, U.S. Distributed Solar and Storage, August 2026 data update.