Apply Window Film to Block the Sun

Project difficulty: Easy

Time to complete: 1-2 hours depending on the number of windows

Materials needed: Window film, utility knife, spray bottle, squeegee

Installing window film in your home is a smart move for several reasons. Primarily, window film helps block unwanted heat and UV rays (up to 99%*) from penetrating windows, which makes your home more energy efficient and could save you money on utilities. 

Moreover, window film can add a extra layer of privacy to any room, reduce harsh outside lighting in the evening or early morning and complement the lighting you already have in place.

Instructions on how to apply window film vary from the very simple to the incredibly thorough. In our steps below, we've simplified where possible but provided specific guidance where it will make a difference. If you aren't careful, you could end up with bubbles and peeling film. Because window film isn't particularly easy to remove, you want to get it right the first time.

  1. Use a soapy water solution (not vinegar or ammonia based) to clean the windows. Some home improvement experts recommend a solution of 1 teaspoon baby shampoo in 1 gallon of filtered water to keep the windows as clear as possible.*
  2. Cut the film into pieces about 1” larger than the actual window pane. 
  3. Spritz the same kind of soapy solution you used for cleaning onto the window again, and remove the back liner from the piece of film you are about to apply. 
  4. Start at the top of the window and apply the film, working your way down. Keep the surface of the film wet so you will be able to easily flatten it out with the squeegee.
  5. Once the film is over the entire window, use the utility knife to trim it, leaving about a 1/16-inch border between the edge of the film and window.
  6. Use the squeegee to push all the air bubbles to the edges. Spray more solution onto the film if necessary to keep the process smooth.
  7. Repeat these steps for each window.