CUB's Natural Gas Price Checker
Below is what Illinois' largest utilities charge for the gas you use to heat your home. The Purchased Gas Adjustment (PGA) is a "supply" charge that changes monthly. It's different from the companies' "delivery" charges, which you pay to get the gas to your home. See what you're paying and how it compares to other utilities.

 Utility CompanyNov. 2014
(cents/therm)
Oct. 2014
(cents/therm)
Change
(cents/therm)
Percent
Ameren Zone 2 (CILCO)  55.0559.09(4.04)(6.84)%
Ameren Zone 1 (CIPS)  55.0559.09(4.04)(6.84)%
Ameren Zone 3 (IP)  55.0559.09(4.04)(6.84)%
Ameren Zone 1 (Metro East)  55.0559.09(4.04)(6.84)%
Liberty Utilities (formerly Atmos Energy)  TBP38.74
MidAmerican Energy  TBP62.46
NICOR  46.0045.001.002.22%
North Shore Gas  51.9355.83(3.90)(6.99)%
Peoples Gas  51.6048.732.875.89%


 Utility CompanyNov. 2014
(cents/therm)
Nov. 2013
(cents/therm)
Change
(cents/therm)
Percent
Ameren Zone 2 (CILCO)  55.0553.671.372.55%
Ameren Zone 1 (CIPS)  55.0553.481.562.92%
Ameren Zone 3 (IP)  55.0553.781.272.36%
Ameren Zone 1 (Metro East)  55.0553.481.562.92%
Liberty Utilities (formerly Atmos Energy)  TBP0.00
MidAmerican Energy  TBP58.67
NICOR  46.0041.005.0012.20%
North Shore Gas  51.9349.012.925.96%
Peoples Gas  51.6044.996.6114.69%


 Utility CompanyNov. 2014
(cents/therm)
Nov. 2009
(cents/therm)
Change
(cents/therm)
Percent
Ameren Zone 2 (CILCO)  55.0557.14(2.09)(3.66)%
Ameren Zone 1 (CIPS)  55.0556.89(1.84)(3.23)%
Ameren Zone 3 (IP)  55.0556.91(1.86)(3.27)%
Ameren Zone 1 (Metro East)  55.0556.89(1.84)(3.23)%
Liberty Utilities (formerly Atmos Energy)  TBP30.79
MidAmerican Energy  TBP40.15
NICOR  46.0047.00(1.00)(2.13)%
North Shore Gas  51.9358.11(6.18)(10.64)%
Peoples Gas  51.6054.65(3.05)(5.58)%
Updated: November 05, 2014
Annual comparison | January through November
In addition to comparing the cost per therm, the following chart includes average usage.
Month


January
February
March
April
May
June
July
August
September
October
November
December
Average
Therms


250
250
150
100
25
25
25
25
25
100
150
200
Most consumers are aware that usage drops during warmer months, which is followed commonly by a drop in natural gas prices. Usage during colder months—when the price per therm can peak—may be ten times greater than during summer months. For example, average consumption in January is 250 therms, while the average in May is just 25 therms.

The following chart compares the usage from the beginning of the year to the end of the current month. It does not include additional fees or taxes.

 Utility CompanyIn 2014In 2013Difference
2014-2013
Pct (%)
Change
Ameren Zone 2 (CILCO) $660.95$617.60$43.357.02%
Ameren Zone 1 (CIPS) $660.95$642.23$18.712.91%
Ameren Zone 3 (IP) $660.95$637.29$23.663.71%
Ameren Zone 1 (Metro East) $644.87$642.23$2.630.41%
Liberty Utilities (formerly Atmos Energy) $474.04$315.85$158.1950.08%
MidAmerican Energy $638.67$642.30$(3.63)(0.56)%
NICOR $606.75$471.00$135.7528.82%
North Shore Gas $761.05$529.06$231.9943.85%
Peoples Gas $733.25$487.63$245.6250.37%
Average Cost $649.05$553.91$95.1417.18%
What is the PGA?
The Purchased Gas Adjustment (PGA) charge is based on the price that a utility pays for natural gas. Under the law, gas utilities are supposed to pass on this cost to customers, without a markup. The Illinois Commerce Commission (ICC) doesn't approve this per-therm charge in advance, but it reviews the charge annually and can order a refund for customers if it finds the utilities weren't using sound business practices to buy gas at a reasonable cost. Depending on the utility, this charge also is called the "cost of gas charge," the "natural gas cost," the "gas charge adjustment," or the "gas supply charge."
What is a therm?
A gas meter measures usage in cubic feet, but your utility converts that figure to a unit of measurement called a "therm" on your gas bill. An average home furnace uses about one therm per hour of heat production.

For more information read Making Sense of Your Gas Bill.