Judging the quality of carpeting means understanding its main characteristics: density, twist and pile height. Denser carpets last longer and feel more comfortable under bare feet. High density carpeting resists matting and wears far better than a low density carpet. Higher twist also contributes to longer life for carpets but can be hard to determine to the untrained eye if not listed (thus ask a salesperson). Pile height is easy to determine, and higher pile usually is better. On stairs, however, you may prefer a lower pile carpeting. All three of these characteristics will affect the pricing, so think about how to balance them for the ways you will use the carpeting.
Choose a fibre for your carpet. Think about where and how it will be used--for example, in a busy area or one with less traffic. Nylon carpet is the strongest, most resilient fibre used today and thus good for high traffic areas. Polyester fibre is soft to the touch but not quite as resilient as nylon. For indoor/outdoor areas, you can use an olefin fibre carpet. Wool is a natural fibre suitable for any area of your house. But wool carpeting tends to be more expensive than synthetic fibres.
Look for a tight twist. Five twists per inch or more is the standard for good quality carpeting. The tighter it is the better the carpet will wear over time. Check that the yarn has been heat set, which contributes to permanence. Also look to see that the cut ends of the carpet pile are tight and neat. Yarn twist is critical to carpet performance and will help it resist changes in appearance and texture.
Check the density by folding back the carpet and looking at the backing. Check to see if you can easily move the carpet tufts to examine the backing. The closer the fibres are attached, the less wear on each individual fibre. Another way to check for carpet density is to press your fingers on the carpet fibres to reach the carpet backing. The harder it is to reach the backing, the denser the carpet. Carpet with high density and more yarn tufts per square inch has a better resistance to crushing and matting.
Check the type of carpet pile since each has different properties. Cut pile is the most common, has a soft feel and is good in the most comfortable areas of your home such as bedrooms, living rooms or family rooms. Loop pile has yarns that are looped and uncut on the carpet surface and can be low or high. These have very good strength and soil hiding capabilities and are good in high traffic areas. The last type is cut and loop pile, which has an interesting surface texture but is slightly less durable than a loop carpet.