Like many outdoor items, sleeping bags are 99% have a down or synthetic insulation. Each with its advantages and disadvantages, simply target the use you make of your sleeping bag to determine the type of insulation that best suits your needs.
There are obviously different insulating qualities of down. You may have noticed the numbers that follow the words down: 550, 600, 650 … 800. This corresponds to the down swelling capacity; the higher the number, the higher it is quality.
By cons, the figure does not correspond to the heat that provide insulation, rather it depends on the amount of fluff inserted into the sleeping bag.
Thus, for 1 gram insulation, down 800 will be hotter than 550 fill down.
Please note that it is quite normal to see fibers escape from the sleeping bag; this is not a sign of a manufacturing defect nor a sign of inferior quality, the warmth of your sleeping bag will not be affected. The most important is not to pull on the fiber, but rather to try to place it inside. It’s the same technique that should be used if your down coat loses its feathers .
Based on topbbacolleges, the advantages of down sleeping bags are mainly lightness and compressibility. It is therefore ideal for expeditions. Despite the water-resistant coatings applied to the insulation, moisture can still affect the thermal capacity of down, so it is especially appreciated for fresh and dry environments.
In brief: lightweight, compressible, warm, durable, less effective in high humidity and very comfortable.
Synthetic insulations are usually sleeping bags heavier and less compressible. However, they are ideal for high humidity since they retain their heat capacity. The possible arrival on milkweed market promises much in the field of synthetic insulation. It is ideal for very wet areas or for casual campers have access to a car since the compressibility and weight are then less of a factor.
In brief: inexpensive, heavier, less compressible, retains its thermal capacity when wet, not allergen.