One vital decision to make is the material that is utilized to fill (or protect) your sleeping bag. One property of fill is "space," the stature the protection accomplishes when the sack is open and permitted to "cushion". The higher the space, the hotter the pack.
Cotton- cotton-fill sacks are comfortable and function admirably on the off chance that you are resting in a warm tent or vehicle, however bad at all in the event that they get wet; cotton assimilates and holds water, getting soaked, substantial, and cold. It isn't useful for exploring, as it is excessively hefty and doesn't pack well to move up or stuff in a sack. In spite of the fact that cotton has its place, in hiking circumstances it is known as the "passing material" since it doesn't protect well when wet, and it's very difficult to dry—so if temperatures fall, it might slaughter you or lead to hypothermia.
Wool- wool repulses water far superior to cotton, and regardless of whether it retains some it watches out for wick it away from the surface, with the goal that you feel dryer. Notwithstanding, it is likewise weighty and doesn't pack or ship well.
Synthetic Fill-These delicate polyester fibers are solid and have great warmth maintenance in cool temperatures, in any event, when wet. Manufactured fill doesn't pack well, either, so it will occupy more space in your rucksack. Great space.
Down Fill-Down is the name for the delicate, little quills that develop close to the skin of a goose and keep it warm. Down sofas, pads and camping cots are delicate and lavish inclination, however down loses warmth when wet. It is the lightest sort of protection; it additionally compacts and stuffs well into a pressure sack for pressing. It is the most costly kind of fill. Due to its capacity to trap and hold air, it has the best space
2. CoatingThe coating of the sleeping bag may be silk fabric, wool or downy—once more, your decision will rely on where and how you anticipate that the bag should be utilized.
Silk-It is viewed as probably the most ideal decision, as it is a characteristic, agreeable and solid texture, and can ingest a lot of water without feeling wet like cotton, yet still is lightweight.
Flannel -It will in general hold water
Fleece- It is acceptable in extra-chilly conditions. You can likewise purchase an additional liner for your sleeping bag to add 5 to 10 additional levels of warmth. On the off chance that you Replace yourself outdoors in warm evening temperatures, utilize the liner alone, on top of a cushion.
The material utilized for the external shell of the pack is another factor. A few materials are water-repellent, others are named waterproof. Some are breathable; others are astounding at keeping out breezes and drafts. Waterproof and windproof are pleasant, however will add to the expense. In the event that your fill is down, a waterproof/breathable shell is ideal. Focus on the foot area—is it built up and extra warm? What about the hood—does it fit cozily and easily around the face? Look at the draft tube (the texture that covers the zipper to forestall heat misfortune) to be certain it is sufficiently liberal, and developed so it will not catch in the zipper.
4. Pillow Pocket
Is there a cushion pocket into which you can either slip an outdoors pad or stuff apparel to make a pad? Having the world's most happy with sleeping bag won't help you a whole lot in the event that you need a cushion and don't have space for one.
Examine the baffles—seams that run across the length of the bag to compartmentalize the insulation. Are they securely sewn? This can affect the warmth and life-span of your bag, because the baffles prevent the fill from shifting around and creating cold spots while you sleep.