Density - The closeness of the yarns in a carpet. Denser pile translates into better quality.

Fiber - The basic material in a carpet, fiber is either manmade (nylon, polyester, polypropylene/Olefin, acrylics) or natural (wool, sisal). There are five fiber types:

Nylon - The most common fiber, nylon is durable and resilient. When treated, it offers good stain resistance and camouflages dirt. It is prone to static, however.

Polyester - This hypoallergenic fiber is resists fading, withstands stains, and offers a variety of textures and colors. Some fibers are recycled from plastic bottles. However, it is susceptible to crushing.

Poypropylene/Olefin - This carpet stands up to sunlight, bleach, and stains, but it is less resilient, which can cause crushing. Color selection tends to be limited.

Wool - Along with lending a luxurious look and feel, wool purifies indoor air, inhibits dust mite and bacteria growth, and possesses inherent hypoallergenic properties. It is the most expensive type of carpet.

Acrylics - Known as man-made wool, acrylic fiber offers the look and feel of wool at a lower cost. It resists static, moisture, mildew crushing, and stains. However, it is not durable enough to withstand heavy traffic.

Pad - Also called "cushion" or "underlay," carpet pad is the thin foam, fiber, or rubber layer beneath carpets. It prolongs the life of a carpet, serves as an insulator, and adds comfort.

Pile - The visible surface of a carpet, pile consists of fiber tufts in loops that are either cut or uncut. Also called "nap." There are four general types:

Cut and Loop Pile -  This style combines lower loops and higher cut piles on one surface, producing pattern, textures, and sculpting.

Level Loop Pile - Short, even, densely packed loops create a durable, easy to clean surface. Berber, one type of level loop pile, typically contains flecks of dark color on a light background.

Multilevel Loop Pile -Two or three varying levels of loops produce patterns both geometric and abstract.

Cut Pile - Featuring loops cut to the same height, this common construction encompasses five styles:

Saxony features tightly twisted cut piles standing straight up.

Plush has closely packed tufts all the same length (longer than Saxony) for a smooth, luxurious surface. Also called "velvet."

Textured carpet mixes twisted and straight piles for a nubby look.

Frieze is highly twisted with fibers curling in different directions for a highly textured look.

Shag is a deep pile carpet with long strands that are slightly twisted and set farther apart for a shaggy appearance.

Considerations

Before choosing a carpet, consider these factors.

How To Clean - Carpet requires regular vacuuming and occasional deep cleaning. Choose a stain- and soil-resistant style to simplify cleanup.

Best for: Bedrooms, living and family rooms, playrooms, and dining rooms.

Pet Friendly? Moderate. Carpet is most prone to damage from messes and traffic, so choose a style that is durable and stain treated, won't snag claws, and disguises pet hair. One benefit: Carpet can actually trap allergens to prevent them from circulating in the air.

Underlayment - Proper underlayment is vital to extend carpet longevity, add cushioning, keep your home quieter, and keep carpet cleaner. Three basic types exist: foam, rubber, and fiber. Check with your manufacturer to determine which is best for your carpet.

Kim Hildenbrand

http://www.hgtv.com/remodel/interior-remodel/carpet-101