Natural Gas Price in Illinois (2025)
Natural gas in Illinois costs $1.08 per therm on average for homes ($11.25 per Mcf, 2025) – 27% below the US average and the 12th cheapest of 51 states and DC. The average customer's bill works out to about $81 a month over the year.
Source: EIA annual residential price (2025) and residential use per customer (2024). Latest monthly figure: $2.03/therm in July 2026 (monthly prices swing with the season).
Gas bill in Illinois by usage
| Monthly use | Illinois | At US average |
|---|---|---|
| 30 therms (29 ccf) | $32.55 | $44.38 |
| 60 therms (58 ccf) | $65.09 | $88.76 |
| 100 therms (96 ccf) | $108.49 | $147.93 |
| 150 therms (145 ccf) | $162.73 | $221.89 |
Average price includes delivery and fixed charges spread over all gas sold. Roughly: 30 therms is a summer month with a gas water heater and stove; 100–150 therms is a cold-climate winter month with gas heat.
Price trend
Illinois's average residential price rose from $11.11 per Mcf in 2024 to $11.25 in 2025 (+1.3%). Nationally it went from $14.50 to $15.34.
Gas vs electricity in Illinois
One therm of gas holds the same energy as 29.3 kWh of electricity. At Illinois's 19.22¢/kWh, that much electricity costs $5.63 versus $1.08 for the gas. Gas furnaces turn 80–97% of that into heat, while a heat pump delivers 2–3 times the electricity it uses. Run your own numbers with the heat pump vs furnace calculator, and see electricity cost in Illinois.
How Illinois compares
- Minnesota: $1.06/therm, about $65/month
- Colorado: $1.08/therm, about $62/month
- Nebraska: $1.10/therm, about $57/month
- Indiana: $1.11/therm, about $68/month
- US average: $1.48/therm, about $76/month.
Other East North Central states: Wisconsin ($1.04), Michigan ($1.05), Indiana ($1.11), Ohio ($1.34).
Frequently asked questions
How much is natural gas per therm in Illinois?
Illinois residential customers paid an average of $1.08 per therm in 2025 ($11.25 per thousand cubic feet), including delivery charges. That is 27% below the US average of $1.48 and ranks 12th cheapest of 51.
What is the average gas bill in Illinois?
The average Illinois gas customer used about 86.1 Mcf (893 therms) a year in 2024, which works out to about $81 a month at 2025 prices, averaged over the year. Winter bills are much higher than summer bills.
Has natural gas gone up in Illinois?
The average price rose from $11.11 per Mcf in 2024 to $11.25 in 2025 (+1.3%).
Is gas or electric heat cheaper in Illinois?
Per unit of energy, gas at $1.08/therm compares with $5.63 for the same energy from electricity at 19.22¢/kWh. A heat pump delivers 2–3 units of heat per unit of electricity, so it can still beat gas – compare with your numbers in the heat pump vs furnace calculator.
Sources: EIA natural gas prices; EIA residential deliveries; EIA number of consumers.