5 fabrics that act like an air conditioner

There are only about 30 days a year when the air temperature is 22°C and the humidity is between 40-50%. In such conditions, not only do you feel like living, but you can move mountains, because it's neither too hot nor too cold.

On the other days, you need to improve your thermal comfort, for example, with appropriate clothing. Here are 5 materials that can react to the microclimate around your body: they manage moisture, accumulate heat, or quickly dissipate it. A bit like natural bodies of water, or – less perfectly – air conditioning.

1. Outlast® – stellar PCM technology

This material, unlike wool, which is most commonly associated with thermoregulation, was not developed in a pasture but in a laboratory. It's a synthesis of high technology and physics.

How does it work? Outlast uses Phase Change Materials (PCM). Microcapsules containing wax are enclosed within the fibers. When the body heats up during exercise or in hot weather, the wax absorbs excess energy and melts, providing a pleasant cooling sensation. When the body cools down, the wax solidifies and releases the accumulated heat back.

The technology was developed for NASA to protect astronauts from drastic temperature changes in space. Today, the same fibers can be found in professional sports apparel, motorcycle gloves, and even in duvets and mattresses. And in thermal sports underwear.

(*** FYI: in our opinion, merino wool does the same thing, only better, because it's natural :) but more on that below!)

2. Linen – humanity's oldest known expert in thermoregulation

Linen is one of the oldest cultivated plants in the world. Although we have known it for thousands of years, in terms of breathability and cooling, it still surpasses most synthetics.

Why does it cool? Linen is distinguished by its very high thermal conductivity. This means it immediately wicks heat away from the skin's surface, making the fabric always feel cool to the touch. Furthermore, the stiffness of its fibers prevents linen from sticking to sweaty skin, allowing for constant air circulation.

In ancient Egypt, linen was considered a symbol of purity and light. Egyptian priests could wear only linen robes, and the bandages used for mummification survived in perfect condition for thousands of years. Linen was poetically called "woven wind." This description particularly appeals to the imagination on a hot day.

3. Tencel (Lyocell) – eucalyptus microclimate control

Tencel is a fiber derived from eucalyptus wood pulp, and its production process occurs in a closed loop with minimal water consumption. It is therefore incredibly functional and very safe for the environment. It's one of our favorite raw materials.

What makes it thermoactive?

Tencel has a microscopic nanofibril structure (miniature threads) that absorbs moisture 50% more effectively than cotton and quickly releases it into the environment. This process creates a natural cooling layer on the skin. Additionally, the absence of moisture on the fabric surface inhibits bacterial growth, preventing the formation of unpleasant odors. In this respect, it is very similar to wool.

Due to its smoothness, comparable to silk, and excellent temperature management, Tencel is loved by manufacturers of luxury lingerie, yoga wear, and bedding.

4. Silk – a protein shield for all weather

Silk is mainly associated with elegance, but its true strength lies in its protein structure (composed mainly of fibroin and sericin), which resembles the structure of human skin.

What makes it ideal for both heat and cold? The low thermal conductivity of silk means that in winter, the material retains a layer of warm air close to the body. In summer, its high hygroscopicity allows the skin to breathe freely and quickly wicks away water vapor, providing a refreshing coolness.

Legend has it that the secret of silk was discovered by the Chinese empress Leizu around 2700 BC when a silkworm cocoon fell into her hot tea and began to unravel under the influence of temperature. China guarded the secret of silk production for almost 3000 years – attempting to export silkworm eggs was punishable by death. Today, both natural and synthetic silk can be bought. The latter is more ethical because silkworms do not die in its production process, but it pollutes our planet more.

 

5. Merino Wool – natural warmth for your body

When you think of wool, you probably imagine thick, itchy sweaters. However, wool from Merino sheep is a completely different category. Its fibers are extremely thin (even several times thinner than a human hair), so they don't prickle, but instead form a soft, delicate structure.

How does wool "air conditioning" work? Well, it's a bit like a lake, or another body of water, that regulates the ambient temperature. By the sea, it's always a bit warmer in winter and a few degrees cooler during heatwaves. Merino can absorb moisture up to 35% of its own weight before you even feel it's damp. In summer, it quickly evaporates sweat, creating a cooling sensation. In winter, it traps air in the microscopic spaces between the fibers, providing excellent insulation against the cold.

For centuries, the Spanish guarded Merino sheep so jealously that attempting to export them outside the country was punishable by death. It wasn't until the 18th century that the first flocks arrived in Australia and New Zealand. In their harsh climate (where temperatures fluctuate from +35°C to -20°C), the sheep developed fleece that protects them in all conditions.

Our fascination with wool, particularly merino, began several years ago. It stemmed from a personal need for thermal comfort. We were looking for a fiber that would be an ideal insulator, as environmentally friendly as possible. Ideally, of natural origin. And after a decade of continuous searching, we still haven't found anything better!