While placing heavy drapes over windows is a sure-fire way to keep your home cozy during the winter months, it also blocks sunlight from entering your home. An alternative idea that helps insulate and lets sunlight in is to use stick-on window film on top of your windows. This self-stick product goes directly onto your window, and it's absolutely clear. It provides an extra layer of insulation that reduces heat loss in the winter, blocks harmful UV rays and -- in the hot summer months -- blocks heat from coming in. It's inexpensive, easy to install and will pay for itself over time.