Most fitted carpet sold today is synthetic, but 'synthetic' covers fibres with quite different properties. Knowing which one you have explains a lot about how your carpet is behaving.
This guide compares the three most common types from a maintenance point of view.
Nylon
Nylon is the most resilient common carpet fibre, recovering well from crushing and standing up to heavy traffic, which is why it is widely specified for stairs and commercial areas.
It responds well to hot water extraction, though untreated nylon is absorbent and can be vulnerable to acid-dye staining from drinks and food colourings.
Polypropylene
Polypropylene is solution-dyed and highly resistant to water-based staining, which makes it popular in family homes and rentals. Its weakness is oil: greasy soil bonds readily and traffic lanes can grey noticeably.
It is also less resilient than nylon, so pile can flatten in busy areas and stay flattened.
Polyester
Polyester feels soft and holds colour well, with good resistance to water-based stains. Like polypropylene it attracts oily soil, and it is less resilient than nylon under sustained traffic.
In practice this means polyester carpet often looks excellent in bedrooms and shows wear faster in hallways.