You can use window treatments and covering to winterize your home. You will be able to save a lot of energy doing this.
Here are some window treatments that can help you keep in more heat during the winter season:
Even with these treatments, they cannot help to decrease air leakage or infiltration. Caulking and weather-stripping around the windows can help to decrease air leakage (draft). Using these two methods will help you save energy which in turn, is saving money. You will be able to keep drafts out of your home. So when it gets cold, your home will be warmer without the cool air.