Middle layer: Wool vs Synthetics vs Down

Layering is a term well-known to all outdoor enthusiasts. If you dress according to this notion, you are always well prepared.


Layering principle consists of three parts

  • The inner layer keeps you dry and warm
  • The middle layer insulates
  • The outer layer protects against the elements


Function of the middle layer

The middle layer’s most important task is to retain warmth. That’s why garments made of wool, down and synthetic material (fleece/Primaloft), all of which have good insulating properties, are the most commonly used materials in this layer. The different materials have unique properties that are essential for comfort on the go. Weather, type of activity and intensity are therefore important factors to consider when you are going to dress in layers.There are also products composed of blends of the different materials, which may be preferable in specific cases.

Which middle layer should I choose?



The classic woollen sweater is a favourite among many, and with good reason. Wool’s thermoregulating properties ensure that the body temperature is kept at a comfortable level throughout the day. A midlayer of wool is a particularly good choice if the intensity and weather conditions vary, as wool has a unique ability to absorb excess heat and sweat without feeling wet or smelling. 



  • 100% Natural, biodegradable and renewable
  • Temperature regulation
  • Doesn't smell
  • Self-cleaning



  • Heat-to-weight ratio
  • Compressibility





A fleece middle layer (often made of polyester) is good on moisture wicking and breathability, making it a great choice for high-intensity activities. In addition, polyester is a durable material that dries quickly. Polyester does not have as good wind and water resistance properties; thus it is best used in dry, low-wind conditions.



  • Moisture wicking
  • Moisture absorption
  • Cheaper material



  • Greater environmental footprint
  • Smells quickly



Down jackets are superbly insulating and have a high heat-to-weight ratio, making down the ultimate choice when you want to pack light. Down works best when it is dry. In high intensity activities, down can feel clammy and when wet it will lose its insulating properties. If you are going to sit still for a while in the cold, then down is a good choice. 



  • Superior insulation properties
  • Compressibility
  • Lightweight



  • Poor water resistance
  • Poor durability (depending on the outer fabric)