TOG and wool: Why is wool superior to synthetic materials in terms of thermal comfort?

When it comes to choosing a garment or accessory designed to regulate temperature, whether it's a duvet or a suit, the term ‘TOG’ often comes up. But what does this term really mean, and why does wool stand out from synthetic materials in this respect? This article gives you a better understanding of the importance of TOG and why wool is the preferred choice for optimum comfort.

What is TOG?

TOG, or Thermal Overall Grade, is a unit for measuring thermal insulation. It indicates the level of warmth a textile can offer. The higher the TOG value, the warmer the material or product. For example, a duvet with a TOG of 10 will be warmer than a duvet with a TOG of 4. This system of measurement is particularly useful for choosing items suited to the season and the sleeping environment.

Wool: a superior natural insulator

Wool is a natural material renowned for its exceptional thermal insulation properties. But what makes it different from synthetic materials in terms of TOG?

1. More efficient temperature control

Wool is capable of naturally regulating temperature according to the body's needs. In cold weather, it traps heat and keeps the body warm, while in warmer weather, it wicks away moisture and provides good ventilation. This ability to regulate is made possible by the unique structure of wool fibres. Wool fibres are made up of small air pockets that act as natural insulators. On the other hand, synthetic materials, such as polyester, do not offer the same thermal flexibility and can sometimes create a feeling of overheating or dampness, which can affect comfort.

2. Moisture absorption and breathability

Another major advantage of wool is its ability to absorb moisture without becoming damp. It can absorb up to 30% of its weight in water without losing its insulating properties. This characteristic allows wool to maintain a pleasant temperature while wicking away perspiration, which is particularly useful at night. Synthetic fibres, on the other hand, tend to retain moisture and can create an unpleasant sensation of dampness on contact with the skin, which can be disturbing and disruptive to sleep.

3. Durability and longevity

As a natural fibre, wool is much more durable than synthetic materials. It retains its insulating properties over the long term and does not deform easily. This means that wool can maintain a high TOG even after many washes, whereas synthetic fibres can lose their insulating capacity over time and with use. What's more, wool is naturally resistant to bacteria and odours, making it a more hygienic choice for products that come into contact with the skin, such as sleepwear or blankets.

4. Comfort and feel

Wool is also renowned for its softness and comfort. Unlike synthetic materials, which can sometimes be irritating to the skin, wool has a pleasant, soft, natural feel. Some wools, such as Merino wool, are particularly fine and soft, making them even more pleasant to wear or use. Synthetic materials, although increasingly sophisticated, generally don't reach this level of natural comfort.

Synthetics: affordable but limited alternatives

Synthetic materials such as polyester or polyamide are often chosen for their relatively low cost and decent insulating properties. However, these materials have a number of limitations compared to wool. While wool is a natural fibre with intrinsic insulating properties, synthetics often rely on chemical treatments or artificial structures to deliver similar performance. Their thermal efficiency can therefore be less durable and more variable.

In addition, some synthetic materials can be more susceptible to heat build-up, leading to a sensation of stifling heat or excessive sweating, particularly at night. What's more, the production of these fibres is often more polluting, which means that, from an ecological point of view, wool remains a more environmentally-friendly choice.

Conclusion: Why choose wool for TOG?

TOG is an essential indicator when choosing thermal products, but the material from which they are made is just as crucial in ensuring lasting comfort. Wool, with its natural properties of thermal regulation, moisture absorption, durability and comfort, is a superior choice compared to synthetics. Whether you're looking for a down duvet, a duvet or winter clothing, wool will not only offer you optimum thermal performance, but also lasting well-being and reduced ecological impact.

So for those looking for optimum thermal comfort, wool is the material of choice, an investment in quality, nature and well-being.


You can opt for wool cocoons or sleeping bags, which are more adaptable in both summer and winter.