Polyester vs Merino Wool: Which Is Best For Hiking?

polyester vs merino wool

When buying everyday clothes, people do not care about the materials they are made of. Yes, they choose apparel according to the season (no one would wear a wool sweater when it’s 104 degrees!). Moreover, someone prefers high-quality clothing to highlight his/her status. Yet, the vast majority are not eager to learn more about the clothes they purchase. Anyway, being aware of textile fiber’s characteristics is crucial when you buy sportswear. E.g., people should be able to make comparison lists like ‘polyester vs merino wool’, etc.

Since retrieving information about this topic is not that easy, we decided to help you with some articles. This time, we’ll confront merino wool and polyester.

If you are new to hiking, you may wonder why we chose to pick these materials above others. Actually, we chose them because they are the most popular fibers among hikers. In fact, polyester has been around for a while, and merino wool has made a recent comeback. Plus, even if they look very different, they have more things in common than you think. Let’s have a look at their features in the details.

Polyester And Merino Wool Similar Aspects

First, merino wool and polyester are very versatile. Both materials, in particular, can be used to make base layers, mid-layers, hats, gloves, and socks. Everyone knows that brands use polyester to make summer clothes and winter garments. But, you probably don’t know that summer garments can be made of wool too. Does this seem strange to you? Well, contrary to popular belief, some types of wool do not only keep you warm.

Merino wool is perfect for the base layer because it can be knitted to superfine yarns. Thus, summer products made from this natural fiber are lightweight and dry quickly. Moreover, even when the fabric is super thin, it will still feel nice on your skin.

Polyester vs Wool – Differences

Even though wool and polyester have a lot in common, they present some differences too. Ready to analyze with us the positive and negative aspects of each of them?

colorful balls of yarn made of wool

Thermal Performance And Weight

Let’s start with the most crucial factor when you go backpacking: weight. Earlier, we mentioned that fashion brands create clothing that can be used as a mid-layer with both materials.

If you read our recent articles, you should know mid-layer is the layer responsible for thermal insulation. Thus, it is a fundamental layer in winter clothing. For this reason, regardless of the textile fiber makers use, the mid-layer is always thicker than the base layer. For example, speaking of synthetic materials, a fleece sweater can be a good mid-layer. This product, in fact, has a top thermal performance, which means it keeps you warm even if it is lightweight.

Merino wool, instead, is not the best material to make mid-layers. This is due to the fact that, thermally, it does not have the same efficiency as synthetic material. In short, a merino wool garment needs to be quite thick to keep you warm. As a consequence, wool products are heavy (they are about 300 grams per square meter). Our suggestion? When you have to buy a piece of clothing that acts as a mid-layer, you’ll better opt for polyester rather than merino wool.

To be honest, if you consider weight alone, synthetic fabric is also the best choice for the base layer. De facto, even if merino wool is suitable for lightweight products, the thinnest fabric weighs 130 grams per square meter. Wool, in fact, must always have a certain degree of density to avoid durability problems. Polyester, on the other hand, does not get damaged even when the weave is very thin.

Sometimes, though, Weight Is Not The Only Thing That Counts…

Finally, sometimes the weight aspect is less relevant than other ones. For example, while hats and gloves made from wool are generally thin, they have some flaws. Wool products offer a good level of warmth, yet they absorb water and, when wet, they become useless. Polyester products, instead, are designed for extreme cold scenarios. Synthetic gloves and hats, in fact, are bulkier and are usually lined with fleece. Moreover, they absorb less water.

Breathability – Winner: Merino Wool

If you’re a follower, you may have already read something about breathable clothing. Breathability is a crucial feature because it is linked to the ability to dry quickly. Speaking of polyester, in particular, we stated that this fabric is super breathable. Yet, if we take this feature into account, merino wool is clearly superior. The only case where the roles are reversed is the mid-layer. The merino wool mid-layer, in fact, is rather heavy and not very breathable.

Durability – Winner: Polyester

Another fundamental aspect to consider is durability. No one wants to buy a garment that gets damaged after moderate use. Compared to polyester, merino wool is not a great material to create durable clothing. In particular, wool is not suitable for intense sports activities, such as running. This depends on the fact that, while running, you experience friction in some areas (armpits, crotch, etc.). And the constant rubbing leads the wool fabric to tear. Polyester garments, instead, last a very long time and are difficult to damage.

Tactile Sensation and Comfort – Winner: Merino Wool

A strong point of merino wool is comfort. This material is very soft and does not cause itching in sensitive individuals. Of course, sensitivity to wool depends on each person. Yet, the diameter of the yarn is crucial. The thinner the yarn, the softer the fabric. In particular, to be considered high-quality, merino wool yarn must have a diameter of less than 18.5 microns.

When you touch polyester instead of merino wool, you immediately get the feeling of synthetic. And, for this reason, many people avoid buying synthetic clothes. After all, not everyone likes to wear a plastic shirt. The tactile sensation improves when the product is made with a mix of polyester and other yarns. For example, many garments are made by mixing cotton and polyester. Isn’t this a simple but efficient ruse to make synthetic clothing comfortable to the touch? Of course, the percentage of cotton is always kept low. In this way, the characteristics of the fabric are not altered.

Drying Time – No Winner

Merino wool is hydrophilic and can absorb 33% of its weight in moisture. This means that when you play sports and sweat a lot, your wool sweater becomes very heavy. Even though this material dries quickly, it’s not going to do it as fast as polyester does. In fact, the synthetic fabric absorbs only 0.4% of its weight in moisture. And this is the reason why polyester never gets heavy.

Yet, when you sweat, a polyester shirt can give you a sticky feeling. Although you won’t be wet for a long time, it’s definitely not a pleasant situation. From this point of view, wool has a consistent advantage. In fact, even when it absorbs a lot of liquid, you don’t get any wet feeling. If you think that this happens with every natural fiber, you are wrong. Textile fibers like cotton, for example, keep absorbing water and remain damp for a long time.

Wool deals with moisture in a particular way. Wool fibers absorb water vapor from your skin and hold it inside and then let it evaporate. With polyester, the process still works in another way. In short, water moves over the fibers until it reaches the surface, where it then evaporates.

Odor Resistance – Winner: Merino Wool

Don’t deny it: regardless of the season, when you do sports, you sweat. Of course, some people sweat more than others. Yet, when there is no washing machine available, this becomes irrelevant. What matters, on such occasions, instead, is to have suitable clothing. Does this seem an unlikely eventuality? Well, you might find yourself in this situation when you go for a multiple-day hike. Believe us, prevention is better than anything else!

In this specific case, our advice is to opt for merino wool. This material, in fact, has natural antimicrobial properties. Thus, even if you use products made of merino wool for many days, they will not smell. We know it, it might be a little gross, but sometimes when you’re hiking, you don’t have much choice. Remember, the golden rule of this sport is to travel as light as possible.

A polyester shirt, instead, will smell even after moderate use. In a nutshell, you can’t use the same one for many days. If you do not have immediate access to a washing machine, choosing polyester means packing more than expected. It’s true, some polyester products have undergone an antimicrobial treatment (such as Polygiene). Yet, after a few washes, this treatment tends to disappear.

a basket full of merino wool


In writing this article, we decided to deal with practical matters first. And to put the price issue among the last ones. Yet, cost also plays an important role when you want to get a whole new wardrobe.

Earlier on, we said that merino wool fabrics are more valuable. So, as you can imagine, wool products are expensive, while synthetic ones are cheaper. A polyester base layer, in fact, is around $10 – $20. A quality base layer made of wool, instead, costs at least $40 – $50. And the price could inflate even more for higher quality wool.

What are the reasons for this difference? Well, among the other elements, there is the fact that raw wool is limited. This is not the case with synthetic fibers because you only need a textile laboratory to synthesize the raw material. The production of wool, instead, is much more complicated. For example, you can’t raise billions of cattle to produce yarn. Are you asking yourself why? Well, first of all, you would need billions of land, water, etc. And that’s not ecologically sustainable!


As you can imagine, merino wool is a more responsible choice than polyester. After all, it is still a natural fiber! In fact, even though they use chemical processes to make the yarn and fabric, wool is 100% biodegradable. Plus, wool doesn’t need a lot of machine washing, which is a major saving. By washing less, you save water, soap, and electricity.

As for polyester products, instead, it takes between 20 and 40 years for them to decompose. Moreover, every time you wash polyester garments, you disperse microplastics into the water. Finally, you can only recycle clothing made of synthetic material if it is made of 100% polyester. Kind of bleak, isn’t it?

Merino Wool vs Polyster: Who is the Winner?

We have reached the end of this polyester vs merino wool challenge. To be honest, there is much more to say on the subject, but we decided to deal only with the crucial aspects. In the end, the targeted talks are the ones that help you choose a product.

Are you wondering which one is the winner between wool and polyester? Well, actually, there is not one. As we said in the beginning, these materials have some differences but share many similarities too. When you need to buy sporting goods, the best thing to do is to make a list. In a nutshell, ask yourself what you want them to do.

If you need products that are durable and lightweight, go for polyester. Also, you’ll want to choose synthetic even if you’re on a tight budget. Are you more interested in comfort and environmental sustainability? Then choose wool. You’ll definitely spend more, but you’ll be satisfied!

Previous articleWill a Snake Cross a Braided Rope?
Next articleWhat’s the Difference Between Men’s and Women’s Snowboard?