Which filling: down or synthetic fibre?
down provides around the same heat performance as synthetic fibre, which is twice as heavy.
down's performance deteriorates significantly if it gets wet. It takes a little longer to dry than synthetic fibre. Down is therefore not really suitable for very damp climates.
down retains its loft far longer than synthetic materials. The lifespan is almost twice as long.
the price of a down sleeping bag is around double that of a synthetic fibre model with a comparable insulation rating. This is due to the fact that the down version will last almost twice as long.
down is capable of regulating the temperature and moisture in the sleeping area. The resulting pleasantly warm and dry sleeping climate guarantees a restorative night's sleep. However, there are limits to the ability to adjust a down sleeping bag. If the sleeping bag is too warm and causes you to sweat too much, the excess moisture can impair the insulation properties of the sleeping bag.