I live in a two person apartment and our bill for December was almost $360 despite us being on break for half of the month and the AC being set to 65 during all of break. We had an Ameren rep check our meter and they said everything is fine and we had maintenance install some weather strips on the window because we also think insulation is a large issue but there doesn't seem to be a significant difference in energy usage. Any thoughts on what could be causing this/ what the next steps should be would be greatly appreciated.