Fashion Q and A

Thermal underwear is popular because it keeps a person’s body warm, as well as insulating it from the cold. In order to do this, the fabric needs to be able to achieve two goals: keep moisture off the skin (this is a process called ‘wicking’) and to keep heat trapped against the skin.

In the early days of thermal underwear, the garments were made out of cotton. While this material is excellent at wicking, it is not a good material for trapping the heat inside the clothing. It was also not easy to clean and keep odour free.

Then manufacturers started experimenting with different natural (wool, cotton and silk) and synthetic (polyester, polypropylene and acrylics) and combinations of these materials to find the ideal match between wicking abilities and insulation.

The best materials for extreme cold weather is Merino wool or Angora silk, while combinations of thinner wool and polyester or cotton and polyester are good combinations for lighter cold spells.

The weave of the fabrics are also important and the popular ‘thermal’ weave has been replaced with the more effective layering of natural and synthetic materials to make up a warm, moisture and odour free garment.