Wool keeps you warm in winter and cool in summer – but why is that?
28/5/2026
Translation: Elicia Payne
Wool is itchy, warm, and… cooling? Yeah, that’s right. Natural fibres keep you warm in the winter and cool in the summer. The secret lies in the fibres themselves.
I used to hate anything made of wool because I used to find it itchy and uncomfortable on my skin. Today, I understand the appeal of natural animal fibres. Their ability to cool in the summer and warm in the winter is undeniably ingenious. Sounds too good to be true? Read on to find out why.
Staying warm in winter
The science behind it isn’t complicated. Your body constantly gives off heat. When you’re naked, that heat is released directly into the surrounding air. When you wear clothes, the fabric traps the heat. Pretty straightforward so far.
But as you’ve probably already noticed, not all fabrics are equally effective in keeping you warm. It depends on the weave, and especially on the material. More specifically, by the number of air pockets trapped within the fibres of the textiles. Since air is a poor conductor of heat, these air pockets form an insulating barrier that traps heat. In addition, with fibrous fabric, less of the fibre’s surface is in direct contact with your skin, which means less body heat is lost.
The rule of thumb is: the more fibrous a fabric is, the more air pockets it contains and the warmer you stay. Thanks to this principle, you’ll hardly feel the cold even in the coldest winter, whether you’re wearing fleece jackets, sheepskin coats or scratchy military blankets.
Staying cool in summer
Given these conditions, it makes sense to assume these fabrics trap heat in the summer, leading to excessive sweating. This is often the case with synthetic fabrics, but not the case for animal fibres such as merino wool. They trap the moisture released by the body in the form of water vapor within the fibres and release it into the warm ambient air. As the material dries, it creates a cooling effect through evaporation and leaves the skin feeling pleasantly refreshed.
The major bonus? It’s (almost) odourless
Clothing made from merino wool, in particular, is said to remain odour-free even after physical activity. It’s true, to a certain extent. The reason being, body moisture is absorbed by the fibres and doesn’t reach the surface of the fabric, where bacteria can settle and multiply. Bacteria already have a harder time attaching themselves to the scaly fibres of merino wool than to the mostly smooth fibres of polyester clothing (link in German). The sweat is still there, but it doesn’t smell because bacteria can’t multiply in it. And since this is the case for all animal hair, it therefore also applies to all pure wools. However, depending on the species, the animal’s natural odour remains in the wool and becomes noticeable in high humidity, which some people find unpleasant.
As with most products, if animal welfare is important to you, it’s worth looking for responsibly produced wool. Especially when it comes to merino wool, you should opt for textiles from mulesing-free farms (link in German).
Header image: Shutterstock: Alexandra Lande
Painting the walls just before handing over the flat? Making your own kimchi? Soldering a broken raclette oven? There's nothing you can't do yourself. Well, perhaps sometimes, but I'll definitely give it a try.
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