Advantages and disadvantages

Contrary to popular belief, down insulation is not made of feathers. Instead, down is actually the fluffy undercoating of a bird's plumage (geese, ducks, and other waterfowl) and looks like interlocking wisps of dandelion fluff. Down works for you just like it works for the bird; it keeps you warm by trapping an abundance of body heat within its tiny clusters. And because it is also breathable, down allows unwanted moisture to escape.
 

The advantages of down are:

• It is warmer than all manmade fibres on a warmth-to-weight ratio basis
• It retains its shape and loft and can last a lifetime if properly cared for
• It wicks body moisture and allows it to evaporate
• It is highly compressible and lightweight
   

But there are also disadvantages:

• Down loses its insulating properties when wet and it is slow to dry
• It requires labour-intensive cleaning
• Down is not entirely hypoallergenic
• Prices of down-filled items are usually higher