Is solar worth it in Illinois in 2026?

For many owner-occupied ComEd and Ameren homes, yes. Illinois Shines REC prices rose for 2026–27 ($80.77/REC ComEd, $70.37/REC Ameren for small systems), the utilities pay a $300/kW smart-inverter rebate, supply-only net metering still credits exports, and summer 2026 rates about 50% above two years earlier raise the value of self-generated power. The exact math depends on your home — the calculator above gives an honest estimate.

Yes. The federal residential credit (Section 25D) expired December 31, 2025 — a system bought with cash or a loan in 2026 earns no federal tax credit. Separately, the federal begin-construction window for new projects closed July 4, 2026, which reshaped how lease and PPA offers can carry federal value.

Possibly, through a lease or PPA — but it's offer-specific and dated. Providers whose projects began construction by July 4, 2026 keep a runway generally through 2030; projects started after that must be in service by December 31, 2027 under stricter equipment-sourcing rules. Cash and loan purchases earn no federal credit. Ask whether a given offer still qualifies — and note battery storage kept its longer federal timeline.

It isn't too late, and there is currently nothing specific to wait for. The federal residential credit (Section 25D) ended December 31, 2025, and nothing on the calendar brings it back. On the Illinois side, the state raised its Illinois Shines REC prices for 2026–27 — $80.77/REC in ComEd territory and $70.37/REC in Ameren territory for systems ≤10 kW AC — and added a $20/REC adder for customer-owned systems taking no federal credit. Both are set for this program year only: they reset every year and are not guaranteed to repeat. PJM's capacity auctions have already set prices through May 2029, which keeps ComEd-area costs elevated at least that long. None of that is a prediction, and none of it is a reason to rush. "Waiting" currently has no specific better deal to wait for — and whether solar fits your roof, your usage and your deal structure still decides the answer.

Illinois' own agency publishes the figure: the Illinois Power Agency models residential solar at $3,734 per kW-dc in ComEd territory and $3,657 in Ameren territory for 2026 — roughly $26,100 for a 7 kW system before any incentive. That runs about 20% above what national comparison sites publish, and the IPA attributes the gap to Illinois construction labor at about 132% of the national median. Compare quotes in dollars per watt rather than headline totals, and remember the federal residential credit is gone for 2026 cash and loan purchases.

There's no single honest number. With a lease or PPA, a fixed monthly payment or per-kWh rate replaces part of your utility bill and depends on system size and terms. With cash or a loan, the "monthly cost" is your financing payment. What matters is the all-in comparison against the utility bill you'd otherwise keep paying — which is exactly what a review prices for your specific home.

For a typical owner-occupied Illinois home the arithmetic usually lands between roughly 9 and 18 years, and the calculator above shows the whole calculation for your inputs. The single biggest driver of that spread is not your roof — it is whether your installer passes through the Illinois Shines REC value, which the state pays to your approved vendor rather than to you. Pass it through and payback shortens by years; keep it and payback lengthens by years. Without the federal credit for cash buyers payback is longer than it was, while higher 2026–27 REC prices, the $300/kW rebate and rising rates push the other way.

Take a 7 kW system on a ComEd home, run through the calculator's default assumptions. The Illinois Power Agency's modelled cost puts it at about $26,100; the $300/kW rebate takes $2,100 off, leaving about $24,000. It would produce about 8,000 kWh a year, worth about $1,160 in first-year bill savings at a blended 14.55¢/kWh. Its 15 years of RECs are worth about $11,600 — paid to your installer, not to you. If that full amount comes off your price, payback is about 10 years; if none of it does, about 18. Same system, same roof: that eight-year gap is the REC pass-through.

Mostly because of one accounting question that few pages address. Illinois Shines pays for your system's renewable energy credits, but under the 2026 rules the state pays your state-approved vendor rather than you, 50% at energization and the remainder ratably over the following six years. It reaches you only if it is priced into your quote. Estimates that add the full REC value to homeowner cash flow show payback years shorter than it is; estimates that ignore it show years longer. Ask any installer what the REC value is for your system and where it appears in your price.

We don't predict rates — nobody honestly can — which is why the calculator lets you set the assumption yourself. The State of Illinois models three annual increase scenarios on its standard Illinois Shines Disclosure Form — 0.5%, 1.7% and 2.5% — so buyers can compare competing offers on the same basis. Our calculator defaults to 2% and lets you set anything from 0.5% to 10%. For context rather than as a forecast: ComEd's summer 2026 supply price ran about 50% above two years earlier, and PJM capacity has cleared at the federal cap three years running, keeping costs elevated through at least May 2029. Any quote built on a high assumed escalation rate deserves a question about why.

Slightly, on paper. ComEd's supply price moved from 10.399¢ to 10.103¢ for October 2026 through May 2027, and Ameren's from a flat 11.326¢ to 10.441¢ on the first 800 kWh. Because the calculator applies today's price to every month, a 7 kW ComEd system's payback range moves from about 9.8–17.9 years to 10.0–18.2, and an Ameren system's from about 8.3–16.0 to 8.8–16.9. Summer 2027 prices aren't set yet, and the largest variable — whether the REC value reaches your price — didn't change.

The Illinois Power Agency publishes capacity factors for residential systems: 13% in ComEd's Group B and 15% in Ameren's Group A. Converted, that is roughly 1,139 kWh per kW-dc per year in ComEd territory and about 1,314 in Ameren territory — so a 7 kW system models to roughly 8,000 kWh a year in northern Illinois. Your actual production depends on roof pitch, orientation, shading and equipment, which is what a site-specific design establishes.

Longer than any payback range on this page. A 25-year product warranty is standard on the panels sold in Illinois today, and the state's own Illinois Shines disclosure methodology assumes output declines 0.5% a year — roughly 88% of original output at year 25, consistent with NREL's published median for crystalline-silicon modules. The component more likely to need replacing mid-life is the inverter, not the panels. Illinois publishes no residential inverter-replacement cost figure at a primary source, so we don't invent one; ask any installer what the inverter warranty covers and for how long.

It depends on your goals. With cash or a loan you own the system and keep all the Illinois value — including the $20/REC adder Illinois Shines pays customer-owned systems taking no federal credit — but earn no federal credit. A lease or PPA means no large upfront cost, and some offers qualified before the July 4, 2026 deadline may still carry federal value priced into the payment. Neither is automatically better; a review compares both for your home.

No. "Free solar" is a sales framing, not a program. Real incentives exist — Illinois Shines REC payments, the $300/kW smart-inverter rebate, supply-only net metering — and Illinois Solar for All serves households at or below 80% of area median income through its own approved vendors. Outside that, someone always pays for the system: you, through a purchase or a loan, or the leasing company, through the payments you make over the life of the contract. If a door-knocker says "free," ask which program, in writing — then check the company against the state's public vendor list.

Both stack the same programs, but the numbers differ. ComEd's supply price is 10.103¢/kWh from October 2026 through May 2027, with $80.77/REC for small systems; Ameren's is 10.441¢ on the first 800 kWh a month, with $70.37/REC, on the separate MISO grid. Ameren's higher modelled production outweighs its lower REC price: on the calculator's defaults, a 7 kW system pays back in about 9 to 17 years in Ameren territory and about 10 to 18 in ComEd's. The first step is confirming which utility serves your home.

It shouldn't — but it's not automatic. Illinois treats a home solar system as a special assessment under 35 ILCS 200/10-10, so the system's value doesn't raise your property-tax bill, provided you file a one-time Form PTAX-330 with your county assessor.

The best available evidence says buyers pay a premium for a home with an owned solar system — Lawrence Berkeley National Laboratory's multi-state home-sales study found one — but the size of that premium depends on the market, the system and the sale, so we don't quote a percentage. Two Illinois-specific facts are documented. First, the system's value is a special assessment under 35 ILCS 200/10-10, so it doesn't raise your property-tax bill once you file Form PTAX-330. Second, an owned system transfers with the house, while a leased or PPA system has to be assigned to the buyer — a known friction point in a sale. What to know before selling a house with solar in Illinois.

It changes the math, not the case. Systems interconnected on or after January 1, 2025 earn supply-side credits for exports — with unused credits carrying forward — instead of full retail credit. That rewards right-sizing, self-consumption, and pairing solar with a battery, and the $300/kW smart-inverter rebate applies alongside it. Sizing for the new rules is exactly what a review does.

Sometimes, and the fine print changed in 2026. Supply-only net metering makes storing and using your own power more valuable, and utilities pay $300 per kWh of storage — but since June 1, 2026 taking that rebate commits you to your utility's virtual power plant. In ComEd territory that means five years of scheduled dispatch plus enrollment in a Qualifying Utility Product — Rate BESH is one option, not the only one — for the life of the battery; in Ameren territory it means VPP enrollment and the battery must be paired with on-site solar. ComEd's virtual power plant begins paying enrolled batteries in 2027. Separately, since September 14, 2026, a ComEd battery connected on or after June 1, 2026 must stay on an hourly or time-of-day supply plan to keep net metering. Whether it pencils depends on your usage pattern, your rate, and how you weigh those commitments — the full battery math.

Heavy shade usually kills the rooftop math — and we'll tell you so. Illinois community solar is the honest alternative: you subscribe to a local solar farm and earn utility bill credits with no panels on your roof, and it's exactly where our eligibility check routes heavily shaded homes. South- or west-facing roofs with decent sun remain the rooftop sweet spot.

Yes — production drops in winter, it doesn't stop. Every production figure on this page is annual: the Illinois Power Agency's 1,139 and 1,314 kWh per kW-dc per year already include short December days and snow cover, so winter is priced into every number above. Cold itself helps — panels lose a little efficiency as they heat up, so a bright, cold day produces well. Snow slides off tilted panels as they warm, and under supply-only net metering the credits you bank in the long summer months carry forward to offset winter bills. More on winter production: solar panels in an Illinois winter.

The check takes about 60 seconds — questions about your home, roof, utility, and bill. If it looks like a fit, our review team reaches out to confirm the details and, if you want, sets a time to walk through real numbers for your home. There's no obligation at any step, and if your home isn't a fit, we'll say so instead of pushing.

Honestly: if you rent, plan to move very soon, have a heavily shaded or end-of-life roof, or have a very low bill, the math usually doesn't justify it yet. That's exactly what the eligibility check screens for — and if your home isn't a fit, we'll say so.