Sleeping bags are designed to offer comfort and warmth. A sleeping bag is essentially a blanket designed for an outdoor setting. Sleeping bags come in different shapes, sizes and with different insulation materials. Each factor contributes to the efficiency of the sleeping bag.
The two main shapes of sleeping bags are rectangular and mummy. Minor variations of the two main shapes are offered. Sleeping bags come in various sizes to fit different people. Cotton, down and synthetic fibers are the most common materials used for sleeping bag insulation.
Cotton provides warm insulation, but as the cotton becomes compacted, the insulation loses some of its ability to keep the cold out. Cotton readily absorbs water and takes a long time to dry, and it is heavier than other insulation choices.
Down feather insulation provides excellent warmth and is lightweight. Down sleeping bags that become wet take a long time to dry.
Synthetic fibers are heavier than down but lighter than cotton. A nice benefit of synthetic fibers is that they do not readily soak up water and dry quickly if they do become wet.
Rectangular-shaped sleeping bags are suitable for camping in tempered climates. Mummy-shaped sleeping bags offer more protection in colder climates because they are shaped to the body and do not allow as much cold air to enter the sleeping bag.
Synthetic fiber insulation is more appropriate for wetter climates. Down fiber is a good choice when weight of the sleeping bag is an issue. Cotton is a good choice for casual campers who want comfort and do not have to worry about weight or weather issues.
Hikers who will be carrying a sleeping bag for long distances should purchase the lightest sleeping bag that will meet their needs.
Casual campers should purchase the sleeping bag that they find most comfortable.
When warmth is a consideration, construction is of the utmost importance. Look at the seams to evaluate stitching. Tight stitching will let in less air. Drawstrings will allow the sleeping bag to be cinched tightly closed to prevent air from entering. Built-in hoods on mummy sleeping bags, keep the head warm and help prevent the loss of body heat.
Sleeping bags come with a temperature rating to let the purchaser know what temperatures the sleeping bag is suitable for. Most people do not know that the temperature ratings are not always accurate. Temperature ratings should only be used as a guide and not the sole deciding factor towards the purchase of a sleeping bag. It is best to look at the construction and materials of a sleeping bag to determine the temperature rating.