Natural gas heating bills have gotten cheaper over time thanks in large part to the discovery of gas reserves in places such as Texas and Pennsylvania. In 2008 the average residential bill was $13.89 per thousand cubic feet, according to Choose Energy. By 2018 that had dropped to about $10.50. "In general, the discovery of large shale deposits, which produce natural gas and petroleum, particularly in Pennsylvania, have increased the supply of natural gas," says Arthur Murray, managing editor for Choose Energy. Still, gas bills vary widely from state to state, influenced by a variety of local factors, adds Murray. With data input from Choose Energy, we've compiled the 25 states with the highest average gas bills for the first nine months of 2019. Want to save money on those utility bills? Check out our review of The Best Thermostats.