Gas prices for six of Illinois’ 9 major utilities were up from a year ago, including Consumers Gas, which is charging a supply rate about 89 percent higher than last September and Liberty Utilities, with a price that is up about 41 percent, according to a CUB review of September gas prices.
Gas utilities file supply prices—called the Purchased Gas Adjustment (PGA)–each month with the Illinois Commerce Commission (ICC). Here’s a summary of the gas supply rates charged by Illinois’ major utilities:
- Compared with last month, six utilities charged lower rates: Ameren Illinois (about 10 percent lower), Liberty Utilities (about 27 percent lower), Mt. Carmel (about 6 percent lower), Nicor Gas (about 8 percent lower), North Shore Gas (about 5 percent lower) and Peoples Gas (about 14 percent lower). Three utilities charged higher rates: Consumers Gas (about 183 percent higher), Illinois Gas (about 7 percent higher) and MidAmerican Energy (about 12 percent higher).
- Compared with September 2025, this month’s prices were higher for six utilities, ranging from about 5 percent higher for Peoples Gas to about 89 percent higher for Consumers Gas. See detailed pricing information below.
September Gas Prices
Ameren Illinois – 43.17 cents per therm (DOWN about 7 percent from September 2025)
Consumers Gas – $1.01 per therm (UP about 89 percent from September 2025)
Illinois Gas – 44.71 cents per therm (UP about 7 percent from September 2025)
Liberty Utilities – 69.89 cents per therm (UP about 41 percent from September 2025)
MidAmerican Energy – 44.07 cents per therm (DOWN about 26 percent from September 2025)
Mt. Carmel – 38.86 cents per therm (UP about 16 percent from September 2025)
Nicor Gas – 33.00 cents per therm (DOWN about 27 percent from September 2025)
North Shore Gas – 38.88 cents per therm (UP about 14 percent from September 2025)
Peoples Gas – 31.45 cents per therm (UP about 5 percent from September 2025)
Note: Your utility is determined by where you live, so you cannot switch from one utility to another. State regulators annually review the utilities’ gas-management procedures to evaluate whether the companies did a reasonable job with their gas purchases, given market conditions, to hold down costs for consumers as much as possible. Regulators can order refunds, although that is rare.
A few tips from CUB:
- Keep the lines of communication open with your utility. If you are having trouble affording your gas bills, it is vital that you contact your utility. Ask if you can set up a plan that gives you more time to pay off your bills, and inquire about energy assistance and energy efficiency programs the company offers.
- Ask if your utility offers a discount program for qualifying customers. Ameren, Nicor, North Shore and Peoples Gas do.
- See if you will qualify for energy assistance when the program opens on Oct. 1. To apply or learn more about the Low Income Home Energy Assistance Program (LIHEAP), visit this state of Illinois webpage. (Also, check out our Step by step guide to applying for LIHEAP.)
- Practice energy efficiency. For tips and information about helpful energy efficiency programs, visit CUB’s Clean Energy page.
- Beware of alternative supplier rip-offs. If a deal seems too good to be true, there’s a good chance it is. If the utility’s gas price increases, remember that it’s due to market factors that also will increase alternative supplier prices. As volatile as gas utility prices are, your best bet for gas supply is likely with your utility and not with an alternative supplier. Read our tips. (Note: Only consumers in Northern Illinois have gas choice.)
- More helpful resources:
- CUB’s Gas page
- CUB’s chart of historical gas prices. Plus, CUB’s gas-price reports from 2026: January, February, March, April, May, June, July and August.
- 2025 gas-price reports: January, February, March, April, May, June, July, August, September, October, November, and December.
- If you want to consider moving away from gas, visit our electrification page and order CUB’s free Better Heat Guide to learn how to make the transition to more efficient appliances, such as electric heat pumps and induction stove tops.
