Using a kit to apply plastic over windows can reduce condensation. This will lower humidity in interiors and contribute to preventing the growth of mold on windows. The film can also cut drafts and keep spaces warmer and bills lower. Window film creates an airspace, explains Jeff Jensen, architectural and builder representative with Renaissance Windows & Doors. ‘This is done with double-sided tape and window film available at hardware stores. It’s not exactly pretty, but it’s effective, and it’s DIY friendly.'