Now is a great time to check all of your windows to make sure that the caulking is in good shape. It is amazing how much cool air you can lose around your windows. A lot of people are not aware that caulking is not a permanent product. It should be checked at least every two years. It will break down due to the weather. Also check the flashing around your chimney. Another good thing to check is the weather stripping around your doors. Air Conditioning is too expensive to let it slip out the door or window.