What is the average electric bill in Illinois?

There is no single honest statewide figure, because Illinois has five kinds of electric utility with different rates. For the two that serve most of the state, at the EIA’s Illinois average of 693 kWh a month: a ComEd household pays about $135.17 in summer and $130.05 in non-summer; an Ameren household pays about $148.00 in summer and $107.83 in non-summer. Every figure is published supply, delivery, tax and fixed charges multiplied out. Widely-published statewide averages currently range from about $110 to about $199 — a spread caused by different usage assumptions, different rate years, and in some cases arithmetic that doesn’t hold up.

About $135.17 a month in summer and $130.05 in non-summer, at 693 kWh of usage. The build: supply at 10.399¢/kWh summer or 9.66¢ non-summer, delivery at a flat 6.228¢/kWh year-round, the 0.126¢ state distribution tax, and $19.07 in fixed charges ($15.26 customer plus $3.81 metering). Note how little the season changes it — ComEd applies seasonality only to supply, so the whole seasonal difference is about $5. Electric-heat and multi-family customers are billed different fixed and delivery charges, and municipal taxes vary by city.

Usually one of four reasons. Your usage is above 693 kWh — likely if you have electric heat, central air, or a larger home. You’re reading a summer bill against an annual average. The figure you found was built from a supply-only rate and left out delivery and fixed charges, which are roughly half a ComEd bill. Or the figure simply used a different usage number: published averages are built on anywhere from 637 to 1,134 kWh a month.

On a typical ComEd summer bill at 693 kWh, supply is about $72.07 and delivery about $43.16 — so supply is roughly 53% of the bill. On Ameren it’s $78.49 supply against $54.13 delivery, also about 53%. That matters because only the supply share is shoppable: switching to an alternative retail supplier changes that portion and nothing else. Delivery, the state tax and the monthly fixed charges arrive regardless of who supplies your electricity — which is also why solar, which offsets supply, attacks the largest single component but never the whole bill.

693 kWh a month — about 8,316 kWh a year — is the U.S. Energy Information Administration’s Illinois residential average. It spans everything from studio apartments to large homes, so it’s a midpoint rather than a target. Heat source moves it more than square footage: an electric-heated home can sit far above it in winter, while a gas-heated home of the same size sits below.

It flips with the season, which is why a single comparison is misleading. In summer, Ameren is higher: about $148.00 against ComEd’s $135.17 at 693 kWh — Ameren’s supply price is higher (11.326¢ vs 10.399¢) and its flat summer delivery charge (7.811¢) exceeds ComEd’s year-round 6.228¢, which more than offsets Ameren’s lower fixed charges. In non-summer it reverses hard: about $107.83 for Ameren against $130.05 for ComEd, because Ameren’s tiered winter delivery rate drops to 4.572¢ on the first 800 kWh. Same two households, opposite answers, six months apart.

Three things stack. Your usage rises with air conditioning. Ameren’s summer supply price rose to 11.326¢/kWh, roughly 39% above summer 2024. And Ameren’s delivery charge switches from a tiered winter structure (4.572¢ on the first 800 kWh) to a flat summer 7.811¢/kWh — about 71% higher on that first 800 kWh. On identical usage, the rate changes alone add roughly $40 a month. Full breakdown: why is my Ameren bill so high.

Both utilities reset their supply price, and Ameren also switches its delivery charge from the flat summer rate back to the cheaper tiered winter structure — which is why an Ameren bill falls much further in October than a ComEd bill does. ComEd’s delivery charge doesn’t change at all. As of August 15, 2026 neither utility has published its new supply rate, and we don’t estimate unpublished figures — this page and its calculator re-date the day they post. Background: what happens to ComEd rates October 1.

It can only move the supply portion — about 53% of a typical bill on either utility — and only if the offer genuinely beats your utility’s Price to Compare, which is the benchmark those offers are measured against. Delivery, the state distribution tax and the monthly fixed charges are unaffected by supplier choice. That’s why a bill rarely moves as much as a supplier pitch implies.

Fixed charges. ComEd bills $15.26 as a customer charge plus $3.81 for standard metering every month before a single kilowatt-hour is counted; Ameren’s equivalents are $8.55 and $5.96. They exist whether you use 10 kWh or 1,000, which is why no amount of efficiency — and no solar system — takes an Illinois bill to zero by itself.

Smaller, but not gone — and the structure matters more than the headline. For systems interconnected on or after January 1, 2025, credits offset the supply portion of the bill; delivery is still charged on every kilowatt-hour you draw from the grid, and the fixed charges stay. So the honest framing is that solar attacks the largest single component of your bill, not the whole thing. Line by line: will I still get an electric bill after solar.

Supply prices come from Plug In Illinois, the Illinois Commerce Commission’s own shopping site. Delivery, tax and fixed charges come from the Citizens Utility Board’s January 2026 rate guide — which reflects the ICC’s December 2025 delivery-rate order effective January 1, 2026 — and from ComEd’s Rate DS and Ameren’s Rate DS-1 tariffs. Usage comes from the U.S. Energy Information Administration’s 2024 data year, the most recent published. Every bill figure here is a published rate multiplied by a published usage number, with the arithmetic shown so you can check it. Where a figure isn’t published — both utilities’ October 2026 supply prices — we say so instead of estimating.