What Is Warmer Silk Or Wool?

In this article, we take a look at the different properties of merino wool and silk and discuss why people assume that merino wool is warmer and especially when choosing their underwear. So, the purpose of this article is to give some right guidelines when buying thermal underwear made of merino wool and silk.

Why is it Important to Wear Thermal Underwear?

A lot of people (especially guys) don't wear thermal underwear because they think it's uncomfortable. There are a ton of reasons why it is important to wear thermal underwear though. Here are a few! Thermal underwear traps air from your body close to your skin. This keeps your body warm. Not only that, but it also keeps your skin from getting chapped from the harsh cold! It's also a lot more comfortable to wear thermal underwear too.

How to Choose the Right Thermal Underwear?

First, think about your goal for buying thermal underwear. For example, are you looking for something that is more fashion-oriented, or are you just looking for something that will keep you warm? You should also pay attention to the overall quality of the thermal underwear.

Also, you should look at the material this clothing is made of. Blends of materials tend to be the warmest ones. Different kinds of thermal underwear are made with different kinds of fabrics, so it's important to know what each does in order to get the best value for your money. It's also important to know what kinds of garments you can wear.

Best Men's Thermals
LAPASA Merino Wool Thermal
  • 100% Australian merino wool
  • Moisture-wicking 
  • Odor-resistant
Fluffiest Beanie
TURTLE FUR Wool Plush Beanie
  • Hand knit
  • 50% Merino Wool/50% Acrylic blend
  • Soft & breathable
Best Women's Thermals
GRENASASILK Women's Thermal Underwear
  • Top & Bottom
  • Ultra-soft silk
  • Skin beneficial fabric

How do Some Factors Affect the Fabric’s Thermal Properties?

The thermal properties are affected by many factors, including size, shape, mass, amount of moisture, thickness, type of fiber used, laminate, layer orientation, layering, fabric construction, fabric finishing, etc. Understanding these factors will help you to see how each of them affects fabric thermal properties. For example, if you have different fabric constructions, the fabric with the best thermal properties will have the highest mass and thickness, whereas the fabric with the worst thermal properties will have the lowest mass and thickness. Also, fabric with the highest moisture content will have the highest thermal conductivity.

What are the Differences Between Silk and Merino Wool Thermal Underwear?

Not knowing the difference between merino wool and silk is not good as both the materials are different and have their own advantages and disadvantages. It's a known fact that silk and wool fibers tend to make you feel cozy and warm. You might feel like merino wool and silk are the same things, but they're actually very different.

The answer to this question is quite interesting. Silk and wool are both equally warm. If anything merino wool is slightly warmer than silk. The reason why wool seems warmer is that it gets warmer at a slower rate. However, wool has poor moisture-wicking properties compared to silk. How about Bamboo base layers?

How do Silk and Wool Keep the Outer Layer of the Body Warm and Why?

Different fabrics have different properties that affect how they keep you warm. Wool is a fiber that breathes, has good resistance to moisture, and is a good insulator. That means the wool is a good material for a jacket because it can keep you warm in cold weather and it's lightweight so you won't feel weighed down. 

thermal underwear

When it's wet, wool can absorb up to 30% of its weight in moisture without feeling damp. But, wool won't necessarily keep you warm when it's wet. It can help, though. The benefits of wool over synthetic fibers Some people claim that wool is more comfortable than other textiles as it can wick away moisture from your skin. Wool is often hypoallergenic meaning that those with sensitive skin often find that wool is less irritating than synthetic fibers. Wool is warmer than synthetic fibers. Finally, wool is biodegradable which means that it can easily be composted after use compared to synthetic fibers that may take many years to break down. The benefit of wool over synthetic fabric is that Some people claim that wool is its moisture-wicking property. 

Silk is a fiber, too. But it's a protein fiber, which means that it's produced from animal products. Wear silk, it's a good insulator for body heat. Its main advantage is that it regulates temperature. If you're in a cold environment, silk pajamas warm you up. If you're in a warm environment wear silk. Both silk and wool are lightweight and come in a variety of colors and textures, but they are most notably different in the way they perform and skim the body. Silk has a fantastically smooth texture and feels like a second skin when worn. 

Natural Fiber: Benefits of Silk and Wool Underwear

While there are several different types of thermal underwear, the most important factor to consider is how warm you need to be. If you're looking to buy thermal underwear for skiing, you'll want something that's going to keep you warm.

Silk and wool thermals are popular for their warmth and breathability, and you can use them in almost any weather condition.


does silk keep you warm

The benefits of silk thermal underwear and why you should buy it:

  1. Silk is a strong and durable natural fiber. It doesn't pill and it keeps its shape and elasticity.
  2. Silk is hypoallergenic and has a natural moisture-wicking property. You will stay dry and fresh for a long time. 
  3. Silk is naturally antibacterial and it doesn't hold odor. The smell stays on for a longer time than it does on cotton. 
  4. Silk is lightweight and smooth. You can use it as an outer layer under your clothes or wear it alone.
  5. Silk is soft and doesn't itchy. It feels and looks luxurious and you won't want to take it off! Some ladies wear silk underwear for the great feeling it gives.


Wool is a natural product that is renewable. Wool is a great alternative to synthetic products because it is hypoallergenic, making it great for people with allergies and asthma. Wool is a natural temperature regulator. It will keep you warm when it is cold and cool when it is hot. Wool will not collect moisture and is naturally resistant to bacteria and odor. Wool is a great alternative to cotton underwear because it will not retain odors and is naturally breathable.


If you are planning to go skiing or snowboarding, make sure to check which material will be best for you. Remember that all of them are great for cold weather. However, we would recommend choosing wool because of its better thermal insulation and thermal resistance.


1. What is the warmest material for thermal underwear?

The warmest material for thermal underwear is wool and especially merino. It keeps you warm even when wet. It also wicks moisture from the skin which keeps the body from absorbing the moisture. This way you can maintain a skin temperature close to normal.

best thermal underwear for winter activities

2. Are silk thermals the best?

Yes, silk thermals are the best, because they not only regulate the temperature but also helps you sleep comfortably. It will give you a cozy feel. You don’t need to wear a lot to keep yourself warm. They are so light, you will forget you have them on. Even your sheets will be at a comfortable temperature. They are so breathable, so you will feel so cool and so fresh.

3. What is the thinnest warmest material?

Silk is the thinnest material available on Earth. It is 10 times thinner than human hair, finer than a baby spider web, more delicate than a baby's skin. A single strand of silk is thinner than a single strand of hair. It is 200 times stronger than steel. It is stronger than steel, yet soft as cotton.

4. Why is silk so warm?

Because silk has more air pockets in it than most fabrics. Air is a great insulator, so the more air between you and the outside world, the warmer you will be. Because silk is so porous, it is warmer than most fabrics.

5. Is silk good for winter?

Silk is one of the best fibers for cold weather -- it breathes and wicks moisture away from the body, and keeps your body temperatures regulated. It is warmer than cotton and absorbs less moisture than wool.

6. Do thermals really keep you warm?

Yes. Thermals are terrific winter wear because they are warm, comfortable, and thin enough to fit under clothes. 

Our #1 Recommendation
LAPASA 100% Merino Wool Thermal

The breathable interlock knit merino wool is perfect for maintaining thermal comfort to keep you cool when it's hot, and warm when it's cold so you can stay comfortable in any season.

Our 100% natural Australian merino wool is ethically sourced from non-mulesed sheep. 

The durable 4-way stretch rib knit hem and snug fit will flex, conform, and move with your body to maintain range of motion and comfort. 

Author - Aleksandra Djurdjevic
Aleksandra Djurdjevic          

Senior Content Creator

Aleksandra Djurdjevic is a senior writer and editor, covering snowboarding, skiing and trends in outdoor winter activities. She has previously worked as ESL teacher for English Tochka. Aleksandra graduated from the Comparative Literature department at the Faculty of Philosophy in Serbia. Aleksandra’s love for the mountains, getting out in the snow on her board, season after season, seeking wild snow adventures across the globe helps her continue to be a top expert at CSG.


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