Nylon for stairs and hallways. Polyester for bedrooms and anywhere soft matters more than tough. Olefin for basements and outdoors. Wool if the budget allows and you want the floor to outlive the decade.
That is the summary. The detail is worth reading, because the fiber on the label predicts less about how a carpet wears than two things almost nobody asks about.
Nylon
The workhorse, and the one to buy if you are only going to remember one thing.
Nylon has the best resilience of the synthetics, which means the fiber springs back after being crushed. That is the property that matters on stairs and in hallways, where the same square inches take a footfall thousands of times a year. It also resists abrasion better than the alternatives.
Modern nylon is usually treated for stain resistance at the mill, and solution dyed nylon has the color built into the fiber rather than applied to it, so it will not bleach.
It costs more than polyester. On stairs, in a hallway, or in a family room that gets real use, it is worth the difference and you will notice it in year five.
Polyester
Soft, inexpensive, and better than its reputation.
Polyester takes color beautifully and gives you saturated shades that nylon struggles with. It is naturally hydrophobic, so water-based stains (juice, coffee, most of what happens with kids) sit on top rather than soaking in. A lot of the very soft carpets people fall in love with in a showroom are polyester.
Its weakness is resilience. Polyester fibers crush and stay crushed sooner than nylon under sustained traffic. It also has an affinity for oils, so greasy soil holds on.
Put polyester in a bedroom, a guest room, a den, or a formal room that mostly gets looked at. Do not put it on the main staircase of a house with three kids and a dog.
Olefin, also called polypropylene
The specialist. Do not judge it by living room standards, because that is not the job.
Olefin does not absorb water at all, which makes it mildew resistant. It is always solution dyed, so sunlight does not fade it. That combination is why every piece of indoor outdoor carpet and every patch of artificial turf is olefin, and why it belongs in basements. More on that in our guide to basement flooring and to indoor outdoor carpet.
The trade-off is resilience. Olefin flattens under traffic and it holds oil-based soil. In a below grade rec room or on a covered porch, that is an acceptable price. In a hallway it is not.
Berber-style loop carpets are often olefin, which is where a lot of people form a bad impression of the fiber. It was the construction, not the material.
Wool
The original, still the best in absolute terms, and the most expensive.
Wool is naturally resilient because each fiber has a built-in crimp that springs back. It resists soiling because of the way the scales on the fiber shed dirt. It is naturally flame resistant. It ages gracefully rather than looking suddenly worn out, and a good wool carpet on a staircase can go twenty years and still look intentional.
The costs beyond price: it will shed for the first few months, it can be damaged by bleach and by high alkaline cleaners, and it absorbs moisture, which rules it out for basements.
If you want a stair runner that will look right for a very long time and the budget is there, wool is the answer. We keep wool pieces on the remnant wall from time to time, and a wool remnant is one of the better deals in the store.
Triexta
Newer, and worth knowing about. Partly plant derived, softer than nylon, more resilient than polyester, with permanent built-in stain resistance rather than a topical treatment. It sits between polyester and nylon on both price and performance, and it cleans very well, which makes it popular with pet owners.
Olefin vs wool, nylon vs polyester, and the rest
The matchups people actually ask about, in one place.
Nylon vs polyester. Nylon resists crushing and springs back; polyester holds color and resists stains better but mats sooner in a traffic path. Nylon for stairs and hallways, polyester for a bedroom that sees light use.
Olefin vs polyester. Olefin shrugs off bleach and moisture, which is why it goes in basements and outdoors, but it crushes faster than anything else here and it holds oil. Polyester wears better underfoot indoors.
Olefin vs wool. Not really a contest on performance: wool is the better fiber in almost every way and costs several times more. Olefin exists for places wool has no business being, like a below grade room or a covered porch.
Nylon vs wool. Wool feels better, cleans well and lasts decades if it is looked after. Nylon is more forgiving of neglect and a fraction of the price. On a staircase that takes real traffic, either will do the job.
The two things that matter more than fiber
Here is what a showroom conversation usually skips.
Density. How tightly the tufts are packed. Bend a sample backward over your finger. If you can see a lot of backing through the pile, the tufts are far apart and the carpet will mat down regardless of what fiber it is. A dense polyester will outlast a sparse nylon. Do this test on every sample you consider. It takes two seconds and it tells you more than the spec sheet.
Twist. How tightly each individual yarn is twisted, and whether the tips are heat-set. Loose, untwisted tips untwist further under traffic and the carpet develops a shaded, matted look in walkways. Look at the tips of the yarn on a sample. Tight, defined, distinct tips are what you want.
Fiber sets the ceiling. Density and twist determine whether you get anywhere near it.
Cut pile or loop
Cut pile yarns are sheared at the top. Plush, saxony, frieze, and textured are all cut piles. They hide seams well and they are the safe choice with pets, because there is no loop to catch a claw.
Loop pile leaves the yarn uncut. Level loop and berber are the common versions. Loops are extremely durable underfoot and excellent in commercial settings, but a single pulled loop can run across a room. If you have a cat or a dog with any interest in the floor, skip loops.
Cut and loop patterns mix both to create texture and a subtle pattern. They hide traffic well, which makes them good in hallways.
What to buy for what
Stairs and hallways: dense nylon or wool, low cut pile or a very tight level loop, textured rather than solid so wear does not show.
Bedrooms: polyester or triexta, whatever feels best underfoot. This is where softness is worth paying for.
Family room with kids: solution dyed nylon or triexta, cut pile, mid-tone with visual texture.
Pets: solution dyed anything, cut pile not loop, color roughly matching the animal.
Basement: olefin, or nylon if the basement is genuinely dry. Never wool.
Rental property: dense nylon in a mid-tone. It costs more up front and gets you through more tenants.
Come put your hand on it
Every one of these fibers feels different, and no photograph or spec sheet substitutes for that. Bring your room dimensions and tell us what happens in the room. We will bend the samples with you.
We are at 2855 Saw Mill Run Blvd on Route 51 in Pittsburgh, parking behind the building. Since 1970, and still family run.
Call (412) 885-1444 or see what is on the remnant wall right now.
