Filament fibers refer to fibers of long continuous lengths, while staple fibers refer to those of shorter lengths, which are about a few inches long. Most natural fibers, such as cotton and wool, are staple fibers. Synthetic fibers, such as nylon and polyester, are considered filament fibers. The natural fiber silk is also a filament fiber, but when filament fibers are cut short, they are considered staple fibers.
When an installed carpet is made of staple fibers, some fibers shed during the first two weeks while vacuuming, but this does not affect the overall quality or appearance of the carpet. This type of carpet is not recommended for people with allergies or breathing problems. Despite the shedding, carpets made with staple fibers are preferred because of their more uniform appearance and solid color. Also, staple fiber carpets are less expensive because they are often produced by the carpet manufacturer.
Carpets made of filament fibers are more expensive because the they are purchased from fiber producers or imported. Filament fiber carpets are less uniform in appearance, as with twisted shag carpets, but they are more resistant to pulling. They also appear lustrous, while staple fiber carpets have dull or matte finishes.