Running cost comes down to wattage, hours and your rate. In Illinois the rate is 23.85 cents per kWh, which is 29.3 percent above the national average. Here is what that means for a space heater.
A space heater drawing 1,500 W costs $0.36 per hour in Illinois. Run 6 hours a day that is $2.15 daily, $64.40 a month and $783 a year, which is $178 more than the same appliance at the US average rate.
Cost by hours used per day in Illinois
| Hours/day | Energy | Per day | Per month |
|---|---|---|---|
| 1 h | 1.50 kWh | $0.36 | $10.73 |
| 2 h | 3.00 kWh | $0.72 | $21.47 |
| 4 h | 6.00 kWh | $1.43 | $42.93 |
| 6 h | 9.00 kWh | $2.15 | $64.40 |
| 8 h | 12.00 kWh | $2.86 | $85.86 |
| 12 h | 18.00 kWh | $4.29 | $129 |
| 24 h | 36.00 kWh | $8.59 | $258 |
Cost by wattage at 23.85 cents
| Rated power | Per hour | Per day | Per month |
|---|---|---|---|
| 500 W | $0.12 | $0.72 | $21.47 |
| 750 W | $0.18 | $1.07 | $32.20 |
| 1,000 W | $0.24 | $1.43 | $42.93 |
| 1,200 W | $0.29 | $1.72 | $51.52 |
| 1,500 W | $0.36 | $2.15 | $64.40 |
Find the row matching the nameplate on your own unit. Within a single appliance category the spread is often wider than the difference between categories, so the label is worth reading.
Heating season in Illinois
Illinois carries a real but moderate heating season, commonly four to five months. That is long enough for equipment efficiency to matter and short enough that payback on an upgrade takes longer than it would further north.
Why Illinois pays what it does
Illinois has a competitive retail electricity market, so the rate used here blends households on the utility default with households on shopped supply plans. If you have never switched supplier you are probably on the default, which is usually the more expensive side of that blend. Only the generation portion of your bill changes when you switch; delivery and outage response do not.
At 23.85 cents, Illinois ranks 40 of 51 from cheapest to most expensive. The Midwest regional average is 16.55 cents. Roughly half of any residential bill is transmission and distribution rather than generation, which is why rates keep climbing even when fuel prices fall.
How this compares across the country
The same space heater on the same schedule, in the cheapest and dearest states:
| State | Rate | Per month | Per year |
|---|---|---|---|
| Idaho | 12.35¢ | $33.35 | $406 |
| Utah | 12.96¢ | $34.99 | $426 |
| Illinois | 23.85¢ | $64.40 | $783 |
| California | 33.25¢ | $89.78 | $1,092 |
| Hawaii | 52.00¢ | $140 | $1,708 |
Lowering the number in Illinois
- Use the low setting when it holds temperature. 750 W instead of 1,500 W halves the running cost.
- Put it on a timer or smart plug. The biggest waste is a heater running in an empty room.
- Turn the central thermostat down at the same time. Adding a space heater without lowering the house setpoint adds cost and removes nothing.
- Close the door and block the draft under it. Zone heating only saves money if the zone is sealed.
- One heater per circuit, plugged into the wall. A 1,500 W heater draws 12.5 amps, which is already at the continuous limit for a 15 A circuit.
Offsetting it with solar in Illinois
This load uses about 9.00 kWh a day. Covering that would take roughly 7 standard 400 W panels at typical sun hours, an array of about 2.80 kW. Because it offsets electricity worth 23.85 cents rather than the national 18.44 cents, the same array is worth more here than the national payback figures suggest.
Resistance heating is the worst possible solar load. It draws full rated power the whole time it runs and there is no efficiency to gain, so the panel count is driven purely by hours of use. Full sizing, including battery and inverter requirements, is on the solar sizing page for this appliance.
Questions people actually ask
[hed_faq]How much does it cost to run a space heater in Illinois?About $0.36 per hour and $64.40 a month at 6 hours a day, using the Illinois average rate of 23.85 cents per kWh.
How many watts does a space heater use?Around 1,500 W while running, with a range of roughly 500 to 1,500 W depending on model and setting.
Is that expensive for Illinois?Illinois electricity runs 29.3 percent above the national average, so this appliance costs $178 more per year here than it would at the US average rate.
Can I lower this without replacing the appliance?Usually yes. Run time is the variable you control, and the hours table above shows exactly what each hour costs. In Illinois you can also shop for a cheaper supply rate, which lowers every figure on this page proportionally.[/hed_faq]