Most people don’t realize how important the type of material in their clothing can be. For casual wear, you can get away with not thinking too much about whether your socks are a spandex or elastane blend. But when it comes to clothing for outdoor trekking, skimping on the details can be a huge mistake.

If you are new to outdoor recreation and are feeling overwhelmed by all the types of clothing, check out this guide on what to wear when hiking.

Two of the most popular fabrics on the market right now are merino wool and polyester. On paper, they seem like they couldn’t be any different, but they have a surprising amount of similarities. For example, they are both remarkably versatile. Base layers, mid-layers, outerwear, innerwear, and everything in between — if you can name it, odds are you can find it in wool or polyester.

But the versatility is part of the issue. Since these fabrics can do so much, they sometimes do too much. It can be hard to decipher whether something is made from polyester because it is a better material than wool, or simply because it is easy to make — the reverse is equally as good a question.

Luckily, you won’t have to find out the hard way or do any extensive research. This review condenses the polyester vs wool debate down into a few of the key points so you can better know which fabric is right for you. To start here is some basic info about both of the fabrics.

Both polyester and wool are easy to dye and retain color well, making them popular yarn bases.

Polyester

Polyester is the biggest synthetic fabric out on the market. The fibers are derived from man-made polymers, which may sound scary. It means polyester fabric is made up of plastic, similar to polypropylene. This gives it a few unique characteristics. It holds its shape well, is resistant to wrinkles and abrasion, is lightweight, and it is harder to stain than other fibers. In part due to the 1970s and the infamous polyester suit, polyester became widely regarded as cheap and uncomfortable, but the fabric has come a long way since.

Merino Wool

When people hear “wool” when discussing clothes, one of the first things they think of are heavy, itchy sweaters and socks. But those days are long behind the world of clothing. Merino wool comes from the Merino breed of sheep, and it has surged in popularity as a versatile and comfortable fabric.

Since it comes from sheep, wool fabric is composed of natural fibers. This means on top of being biodegradable and a renewable fabric, Merino wool is also naturally odor-resistant. Natural fabrics are also much better at handling heat, so you are much less likely to burn or melt them while ironing than synthetic fabric.

Durability

Nothing is quite as frustrating as spending a bunch of money on a nice piece of new clothing, only to have it get destroyed after only wearing it a few times. That’s why you need to make sure that the clothes you are buying are made from durable fabrics.

Remember how polyester is made from plastic? Plastic’s most impressive quality is its versatility, but its durability is a close second. A well-kept polyester jacket will last ages without every stretching, shrinking, or wearing thin. The construction of the tightly woven synthetic fibers also means you aren’t likely to tear or rip the fabric on an exposed nail or branch. In general, polyester is much tougher than Merino wool.

Though, that isn’t to say that Merino wool is flimsy. It’s still a fairly durable fabric, just not AS durable as polyester. It does require a bit more care to last as long, but it can be done. One specific disclaimer in the category is abrasion. Merino wool can wear out quickly when exposed to high rates of friction, so runners will see the thighs and armpits of Merino wool clothing run thin pretty quickly.

Polyester also has its own Achilles Heel for durability. It is way less tolerant of heat than Merino wool. This won’t come up too often since the temperatures required for it are somewhat high, but polyester will melt, burn, warp, etc. In temperatures that won’t hurt Merino wool nearly as much. So, ironing, high-temp drying, or if you leave it next to something like a stove eye or a campfire, can all ruin a piece of polyester clothing in mere moments. Merino wool would eventually get destroyed in these conditions too, but they can handle them for way longer, giving you more time to save them.

One of the biggest concerns is that polyester is made from plastic, meaning that any clothes you get made from it will not be biodegradable.

Breathability

This quality is often overlooked when considering clothes and fabrics. You want your coat to be sturdy and robust enough to provide you with ample protection, but you don’t want it so thick that you end up just feeling stuffy and uncomfortable. You should always make note of what fabric an article of clothing is made of because it can heavily affect how breathable it is.

Unless it is a high-quality polyester woven tightly together, typically polyester fabric is more porous. Despite this fact, it is not as breathable as Merino wool. This has to do with the way the individual wool fibers and polyester fibers are shaped. As long as the fabrics you are comparing are of similar thickness and weave type, a Merino wool garment will have better breathability over a polyester one.

One corner case where polyester overtakes Merino wool is specifically when dealing with layers. A high-quality polyester mid-layer will usually be a more breathable option than a woolen mid-layer. Merino wool is a spectacular fabric with high breathability on its own, but it can be finicky when mixing with other fabrics. If you can get a full set of layers all made of Merino wool, then you’ll be fine, but if you start mix-and-matching, you can cause the magic of Merino wool to be disrupted and create a stuffy mess.

Related to the topic of breathability is the specific comparison between the drying process for these. Whether pulling them from the washing machine or getting caught in a rainstorm, polyester garments are quick-drying when compared to Merino wool garments of similar type and quality. Polyester is less absorbent overall, meaning it has less water to evaporate before it becomes dry. That being said, when wet, Merino wool will feel much less clammy and uncomfortable against the skin than polyester due to its natural moisture-wicking properties. More on this in the section about temperature control.

Comfort matters

Form and function are only part of the equation. The best looking and most effective clothes in the world won’t make you happy if they are uncomfortable. There are plenty of people who judge clothing first by how comfortable it is. You don’t have to go that far, but definitely don’t ignore it as a factor.

Synthetic materials like polyester have a bit of a reputation for being uncomfortable. Plastic is not exactly people’s first choice when it comes to comfort, and your clothes will definitely feel plastic-like if you chose some low-grade polyester. This is why most clothes you see are polyester blends. Fabrics like cotton are mixed in to help the discomfort, but percentages are kept low to avoid changing the composition of the clothing item too much.

The higher the quality of the polyester you buy, the better it will feel. But there is definitely a curve to the pricing, as it is hard to get polyester fine enough to feel as good as other fabrics. Even at the top of the quality spectrum, polyester clothing can still feel unpleasant to people with sensitive skin or athletes whose frequent movement causes increased friction against the skin.

Merino wool, on the other hand, is well known as an incredibly comfortable fabric. Unlike with polyester, there isn’t too much of a curve when it comes to comfort to pricing ration. Merino is already a quality wool, so it is hard to make something bad out of it. This is the reason why Merino wool is the primary choice when it comes to base-layers. Plenty of people would choose to wear a Merino wool t-shirt casually, and almost no one would do so with even a polyester blend shirt.

Cold weather

Wool and polyester are perhaps best known for their use in mid-layers, the one most important for insulating you from frigid temperatures. You’ll also see them used for things like gloves, hats, and scarves. This isn’t by mistake either, they are both phenomenal options for staying insulated in the cold weather.

Wool in general is known for being a warm fabric, so you might be inclined to think merino wool has an edge in this category. In reality, polyester stacks up to it pretty well. The quality of the specific fabric as well as its thickness and density have a way bigger effect on your ability to remain warm than what kind of fabric you chose. 

That being the case, polyester does technically have a small advantage here. Since it is lighter than merino wool, you can create an equally thick and warm garment that is lighter than its merino wool counterpart. In a measure of pure cold weather combating, these two fabrics are neck-and-neck.

Warm weather

The type of fabric your clothes are made of is just as, if not more, important when considering warm weather. You might suspect that since merino wool and polyester are both great at keeping in body heat, that they’d be terrible choices for high-temperature garments. However, since they are so breathable, they are both great choices that won’t cause you to overheat.

Merino wool has a considerable advantage in this category because of a few unique factors. As mentioned earlier, it is the more breathable of the two fabrics, so naturally, it allows air to flow well and help keep you cool. Another minor point in its favor goes back to the comfort discussion — you are more inclined to wear less clothing in warm temperatures, meaning you will rarely want to go above base-layer clothing. Since merino wool is more comfortable as base layers, it gets an edge over polyester when it comes to warm weather garments.

A much more tangible advantage merino wool has over polyester is how much better it is at moisture wicking. Due to the way the merino wool fibers are constructed, the fabric is naturally one of the best at wicking away moisture. What this means is that it pulls sweat away from the body while it is a vapor, after your body heat has caused it to evaporate. The sweat then passes through to the surface of the merino wool garments and dissipates right away, preventing you from getting damp and overheated.

This natural wicking property part of the reason merino wool socks ranked so highly in our review of the best socks for sweaty feet.

Polyester fibers are much less effective at this, and usually absorb and transport the sweat once it has condensed against the skin. This can lead to the unpleasant clammy sensation mentioned in the breathability comparison. Outside of discomfort, it causes you to sweat more and feel warmer because the sweat is pulled away before it can complete its job. Plus, your body wastes energy from having to heat the surface of the garment to evaporate the moisture away.

Odor control

This might not be as big a concern for people that don’t regularly participate in intense physical activity or extended trips away from a washing machine. But anyone who has ever gone on a backpacking trip will be able to confirm that clothes start to smell bad after a while — even worse than yourself sometimes.

Luckily, merino wool is naturally antimicrobial. That doesn’t mean clothes made from merino wool fabric will never smell bad, but you have to subject them to much worse than your average shirt. The wool fibers are also capable of absorbing the smells that do accumulate on them, meaning they can’t escape and offend your senses. But when you wear the garments, the odor-causing bacteria is pulled right out. It sounds a bit gross, but it isn’t a whole lot different than hitting a shirt with air freshener — which many people are guilty of and don’t care to admit.

Polyester doesn’t even begin to do the same thing. Unless you get a polyester fabric that has been specifically treated with an antimicrobial finish, clothes made from this fabric begin to smell almost immediately. Even if you get the treatment, it wears off eventually, especially if you wash the garments often. Some of the treatments leave their own odd smell too, which can defeat the purpose if you are bothered by the odor.

This category isn’t even remotely close. If you need to make sure your clothing can stand up to some use before it starts to reek, you need to be looking for merino wool clothing.

Pricing

Let’s be honest, quality and functionality are important, but sometimes you can’t afford to go all out on a pair of gloves and a jacket. If you are shopping on a budget or don’t mind sacrificing some advantages to get a smaller price tag, here is the reality of the numbers:

Polyester clothing is almost always cheaper than merino clothing. This is true across all the different types of clothing and throughout the various levels of quality. There are some corner cases where they are about the same price, but rarely will merino wool be cheaper than its polyester equivalent.

This is just the nature of the fabrics. Since polyester is a synthetic material derived from plastic, it is much easier to source and manage than wool that has to be grown, gathered, and processed from a specific breed of sheep. 

Wool and polyester have been popular choices for outdoor clothes for a while, and they have recently made a comeback as a stylish suit material.

Final Verdict:

The comparison between these two popular fabrics is much closer than expected. Partly because they both have roughly the same number of advantages over the other, but also because some of the advantages are by such narrow margins that it’s questionable if they even count. Fundamentally, the answer to which of these fabrics is better for you comes down to what you value most.

If you are looking for an inexpensive but durable fabric that doesn’t require too much fuss, then polyester is for you. If you prefer a comfortable fabric that fights odors and is great for regulating body temperature, then merino wool is the best choice. If you still feel uncertain in this comparison, then try to keep in mind how you most anticipate using the item of clothing. Running, rock climbing, and similar pursuits are better complemented by polyester. Casual wear, hiking, and comparatively less physically demanding activities are better left to merino wool.

Bonus tip: If you’ve been bothered by all this talk of just the outdoorsy forms of merino wool and polyester then check out this video discussing the pros and cons of wool suits vs polyester clothing: