Ameren Missouri residential and business customers will pay an average of $1.60 a month less for natural gas compared to last winter under a new purchased gas adjustment (PGA).
The lower rates, approved by the Missouri Public Service Commission, are the result of lower wholesale costs.
The new PGA became effective Thursday for Ameren Missouri's 127,000 gas customers.
 This season, Ameren Missouri customers in Jefferson City are expected to pay an average of $0.67 per one hundred cubic feet (Ccf) of natural gas, which includes the cost of interstate transportation, leased storage, and the natural gas commodity.
During the 2011-12 heating season, those customers paid an average of $0.75 per Ccf.
Monthly bills are based on the actual amount of natural gas used by a customer.
 The PGA reflects the wholesale cost of natural gas, plus the cost of transporting gas to the company's system. The cost reduction is passed on to the customers - dollar for dollar - through the PGA without a markup in price.
"Although natural gas prices were higher last year, our customers' total heating season bills were lower than normal because the 2011-12 heating season was uncharacteristically mild," said Jim Massmann, Ameren Missouri's gas supply manager. "Even with the lower natural gas rates this winter, the return of normal winter weather may result in higher overall winter heating season bills as compared to last winter."
 Ameren Missouri also offered a reminder to customers that they can reduce their natural gas usage by installing more efficient natural gas equipment. Through Dec. 31, Ameren Missouri is offering rebates for a variety of natural gas appliances. Visit ActOnEnergy.com for details and information about rebates for natural gas furnaces and boilers.