Your gas bill is about to change yet again. National Fuel Gas announced Monday that gas costs will increase by 4.3%. The typical residential customer will see about a $5.00 increase in his or her monthly bill. National Fuel officials said the quarterly adjustment comes after colder temperatures late in the season, which sent the market price of gas up. Officials said the change should have a minimal impact on customers' bills in the spring and summer months. The utility says customers' bills were 21% lower this year than last as a result of lower gas costs.