Car windows reject 23 to 28 percent of ultraviolet sunlight, while tinted window films reject 95 to 99 percent of UV rays [source: International Window Film Association]. Window tinting also provides increased shatter resistance in case of accidents or break-ins.

Check your state's laws to find out which of your car's windows you may tint and whether you need certification to tint windows.

Follow the manufacturer's directions for your window tint.

Besides the window tint and the solution it came with, you'll need:

  • Window cleaning solution
  • Sponge
  • Single-edged razor blade
  • Utility knife
  • Squeegee
  • Lint-free cloth

When applying window tint, remember:

  • Tint your car's smallest flat windows first. This way you'll get used to working with window film.
  • Apply the film in a dust-free, well-lit, shaded place.
  • Apply the tint when the air temperature is between 40 and 98 degrees Fahrenheit (4.4 and 36.7 degrees Celsius).
  • Be careful not to crease the film.
  • Wet your fingertips to avoid getting fingerprints on the film.
  • Have a friend help you. Applying the film is easier with two people.

Here's what to do:

  1. Clean the window inside and out, including the gasket holding the window in place. Use a razor blade to scrape off any residue.
  2. Wet the window's exterior.
  3. Measure the outside of the window.
  4. Unroll the film onto the inside of the window, with the liner facing out. Trim the film to fit. The film's bottom edge should extend ¼ to ½ inch (.6 to 1.3 centimeters) below the top of a roll-down window's gasket.
  5. Roll the window down about two inches (five centimeters) before trimming the top of the film.
  6. Peel off the film liner. Spray the exposed adhesive with application solution.
  7. Spray the window's interior generously.
  8. Remove the liner from the window's exterior. Don't let the film touch itself.
  9. Stick the film to the window's interior, leaving 1/8 to ¼ inch (.3 to .6 centimeters) at the top of the window.
  10. Spray the film.
  11. Squeegee top of the film to the glass.
  12. Roll up window.
  13. Slip the bottom of the film underneath the window gasket.
  14. Squeegee the film onto the window, pushing bubbles out to the edges.
  15. Dry the film with a cloth wrapped around the squeegee [Source: Automotive Tint Installation Instructions].

The film will take seven to 10 days to cure.