Illinois Electricity Cost Calculator
Use 15.87¢ per kWh and 698 kWh per month as a consistent Illinois benchmark, then replace both with your utility data.
What the Illinois numbers mean
Illinois is a mid-range state in this planning table at 15.87 cents per kilowatt-hour. Applying that price to the EIA-derived residential average of 698 kWh produces a typical variable energy charge of about $110.77 per month, or 8,376 kWh and $$1,329 per year. This is a benchmark rather than a tariff: an actual Illinois bill can include fixed customer charges, tiered blocks, fuel adjustments, taxes, time-of-use periods, or demand charges.
The consumption figure places this example in the lower-use part of this dataset. Weather, electric space or water heating, air conditioning, home size, occupancy, and efficiency explain much of the household-to-household spread. Use twelve actual billed kWh totals when sizing solar. Dollar totals alone are less reliable because a fixed charge cannot be offset by producing energy.
A south-facing, unshaded fixed array is represented by a planning production factor of 1,350 AC kWh per installed DC kW each year. At the typical annual use, that suggests roughly 6.2 kW or 16 400 W-class panels before roof-specific modeling. Shade, azimuth, tilt, snow, temperature, equipment losses, and utility export rules can move production and savings. The value is best used to create a comparison case, then replaced with a site model and contractor scope.
Sources
- EIA — Electric Power Monthly, Table 5.6.A (2024 annual) — Rate basis for Illinois.
- EIA — Form EIA-861 state residential sales and customers (2023) — Average monthly consumption basis.
- NREL — PVWatts Calculator documentation (2025) — Solar-yield modeling conventions.