ape to affix the film to the window fram, then use a conventional hair dryer (not included) to shrink the film into an airtight lining over the window. The film helps prevent drafts and heat loss to provide a drastic increase in energy efficiency.A properly sealed home can cut energy costs by hundreds of dollars a year. This simple solution is easy to install, affordable, and works warming wonders.Product Feature● Roll-up indoor window kit contains everything you need to insulate 4 standard 3′