Wool is nature’s very own functional fabric, and so far, nobody has been able to reproduce a synthetic fibre with the unique properties of wool. Nature had actually solved the problem of freezing and sweating long before any of us started researching it.

We developed our Ullfrotté Original fabric in the early 1970’s in Östersund, Jämtland, Sweden. It’s hardwearing and is made up of fine merino wool, polyamide/polyester, and most of all – air!


Air? You might be asking yourself. Yes, it’s not actually air that makes you lose heat so much. But fabric does. Our fabric is a terry-knit textile, with one side flat-knitted and the other made up of terry loops. The fabric’s fluffy terry loops combined with the wool’s crinkly fibres create a tricot that that traps a lot of air. In fact, 80 per cent of the fabric consists of air. The airy bodice has limited contact with the body, which means there are fewer points where the heat can escape. When you wear a Woolpower undergarment next to your skin, you can insulate your own body heat. The wider the layer of air you can keep around your body, the more heat you can retain.


At the same time, the fabric easily wicks moisture away from the body. When the body sweats, pressure increases inside the clothes. Moisture molecules strive to get out to where the air is cooler and pressure lower. If the fabric is sparse and the fibres have the right properties, they help transport the moisture away from the body. Ullfrotté Original helps to keep you warm even when the fabric is damp. And in contrast: when it’s warm outside, the undergarment keeps you cool for the same reasons. But since wool is a natural textile, it doesn’t smell, even after you’ve been sweating.


Merino wool is a very fine, soft and crinkly wool, perfectly suited for clothes that are worn next to the skin. The wool in Ullfrotté Original is 22 thousandths of a mm thick. That creates a  comfortable wool, that’s also strong.

However, since merino wool is crinkly it isn’t so hardwearing. To ensure that the clothes we make are as hardwearing as possible, the wool is mixed with one-third synthetics. But closest to the body is mostly merino wool.


Once you’ve had your Woolpower garment for a while, you might notice that it becomes a bit bobbly. That’s nothing unusual can naturally be explained by the fact that we make our clothes from natural materials. The bobbles do not reduce the functionality in any way. We have chosen to retain the crinkly nature of the yarn, instead of brushing it out. We don’t spin the yarn so hard either and knit it finally as loosely as we can. All of that combined means that that material can become bobbly over time. But we do it that way to be able to trap as much air as possible in the garment to keep you warm. And also, it makes the material super stretchy and it never clingy.



The keratin in wool naturally breaks down the bad-smelling bacteria from the skin. At the core of wool’s fibres are two types of cells that absorb different amounts of moisture. One type swells more than the other causing a constant motion friction between the two. This characteristic creates a mechanical self-cleaning effect.


The crinkly nature of the wool fibres binds large amounts of air and provides good insulation. The air between the fibres reduces heat transmission in the fabric and thereby has an insulating effect, both against heat and cold. Merino wool contains up to 40 crinkles per centimetre giving it a high degree of insulation and also limiting the number of contact points between the fabric and the body.


The surface of wool’s fibres is water repellent, which prevents bacteria growth and thereby bad odours. Woollen clothes don’t need to be washed often, and instead do well being aired in damp weather. The surface of wool’s fibres is covered with small scales, which means that woollen clothes can become bobbled when washed. The scales can be removed with treatment so the wool is machine washable. Woolpower’s clothes can be washed at 60 degrees without shrinking. Find out more under Washing tips.

Läs mer under Tvättips.


Air gaps in the fabric increase the insulation of the body’s heat. That’s how a loose-knit garment is warmer than a tight-knit one. And that’s why Woolpower LITE clothes that are made of a tight-knit fabric, are cooler even though they actually contain more wool than Ullfrotté Original clothes. LITE clothes are good when it’s warmer outside as the fabric helps to cool the body.


When moisture gets absorbed, something known as absorption warmth occurs through a chemical heat producing process. Heat energy occurs when water molecules and polar molecular groups of the fibre collide. The collision is so powerful that it creates heat. This process continues until the fibres are saturated with water molecules. So our undergarment provides heat, even when it is damp.


Wool is hydrophobic and can attract water vapour, or rather moisture from the body. Wool can absorb moisture both between its fibres and inside the fibres; leaving the wool next to your skin feeling dry even if it’s moist. Wool fibres can absorb up to 30 per cent of its own weight in moisture without feeling damp.


The micron count, i.e. the thickness of the wool fibre in thousandths of a millimetre is used as a quality criterion. Fine wool is between 17 and 23 microns. When wool is perceived as itchy, it’s because there are coarse fibres in the wool that don’t flatten against the skin, instead they stick straight out. The finer the wool fibres, the softer you experience it. Coarse fibres in excess of 28 microns may feel itchy. Woolpower’s undergarments don’t itch in the slightest.


When the moisture levels inside the garment are higher than outside, the wool works actively to absorb the moisture and transport it through the fabric until the level is equal on both sides. As the moisture is transported to the outside of the garment, the heat insulation increases and you stay dry.