When the weather is cold outside, it is not such a bad idea to do something in order to stay warm inside. One idea here is to make sure that your windows are properly insulated. I remember having bad windows in my apartment in the past. I did not take any steps in order to insulate them as it was an apartment that did not belong to me. I felt that insulating the windows in the apartment was too big project for me. Right now, I would not hesitate to insulate any windows. I heard from a few sources that your energy bills can get a lot lower once you make sure that no cold air has any chance to get into your house from the outside.