If you've ever sat near a window on a winter day, you know the cold temperatures can sneak through the glass. This problem costs you hundreds of dollars in heating expenses and makes your home more uncomfortable.
There are ways to keep the cold air out and the warm air in during the winter. In fact, these changes will also keep the warm air out and cold air in during summer.
First, caulk around the perimeter of your windows. If you have an older house, its important to check caulking after about 5 years when it will start to decompose. Use your hand to feel around the frames of your windows to see if any cool air is escaping into the house. Just plug up those leaks with caulk.
Second, purchase a shrink film window kit like THIS one. Its easy to install the sheets over your windows and the difference they make is surprising. If you follow the instructions properly, you'll never even know the film is there.
Third, close blinds and drapes when possible. During the evening and while you're at work, you can keep the cold temperatures out by keeping the windows covered with blinds and drapes.