The sleeping bag is a combination of overquilt and underquilt putting the together for convenience of sleeping at outdoor field. Except with those places with particularly low temperature such as remote mountains, it is quite all right to use thin overquilt and underquilt used at home from late spring to early autumn, of course considering the space availability of user’s vehicle. However, in the winter season commencing from late autumn to early spring, the sleeping bag is the one of most crucial camping equipment.
In order to enjoy exciting and pleasurable camping upon climbing mountains with a backpack full of gears and foods in cold winter, it is certainly necessary to bring a sleeping bag with substantially excellent insulation performance. For such purpose, the easily shrinking duck down or goose down sleeping bags with expensive price tags but providing convenience of carrying are usually used. In the meantime, the auto-campers in general use the hot water boiler or electric blanket, stoves and etc. for heating, they do not need to use the expensive sleeping bags. Of course, considering the risk of power outage at any camping sites which may happen during the use of electric blanket, or in order to simply prevent the risks of any emergency situations, equipping the sleeping bag with excellent insulation performance must be considered as an essential gear when no auxiliary heating device is used even in case of auto-campings.
All the sleeping bag manufacturers show the cold-proofing temperature characteristics on a label, following the common marking procedure, provided that individual indication may be a little different by the specific need of each manufacturer. Some manufacturers’ products show no separate indication or indicate their own specific markings with no solid scientific background.
Comfortable Sleep Temperature
Temperature allowing sound sleep at comfortable posture for an ordinary female user having experience of using sleeping bag.
Sound Sleep Temperature Tolerance
Temperature allowing sound sleep at crouching posture for an ordinary male user having experience of using sleeping bag.
Temperature not bearable for a female user over 6 hours having experience of using sleeping bag, which may accompany with a risk of hypothermia. The campers staying out in between the sound sleep temperature tolerance and extreme temperature can only avoid a serious situation caused by hypothermia, which may try to take sleep but hard to keep cold away.
Classification by Sleeping Bag Type
Envelope Type (Square Type)
Being a square shape, the envelope type sleeping bag offers enough space particularly at underbody area, with which the most of these sleeping bags are made with sufficient sizes. This type of sleeping bags were used to be of envelope type or zipper opening type at 3 sides, but the recently developed products often have a completely divided construction between top and bottom. With that feature, the recently developed sleeping bags allow the use for a family by connecting the multiple numbers of sleeping bags. When the children are young enough, the connection of 3 sleeping bags provide sufficient space for simultaneous use of 2 adults and 2 children.
Depending on the ambient temperature, the recently developed envelope type sleeping bags can be divided by top side and bottom side for use as overquilt and underquilt, allowing temperature control in many ways. Yet, in comparison with the mummy type, these types of sleeping bags have certain disadvantage of complication for sufficient insulation performance at shoulder and head areas. Recently, some newly developed sleeping bags supplementing such disadvantage are sold in the market, but it does not matter that much with ordinary auto camping activities.
The mummy type sleeping bag in English, also called as mirra in Portugese, is an exact orthography in foreign language. Being a sleeping bag wrapping head and shoulder areas completely, it offers high insulation performance requiring a relatively small carrying space.
Those kids particularly with untidy sleeping habits may feel stuffy. It may be different by each person’s own character, but the mummy type sleeping bag is suitable for mountain camping, while the envelope type (square type) sleeping bag is good for common auto camping with family. Being only opened by one zipper either right or left, it would be difficult to effectively regulate the body temperature with various opening methods.
Classification by Insulation Material
Duck down / Goose down
There are various products available in the market, offering different performances depending on the quality of down feathers, amount filled up and production system, but basically this type of sleeping bags are of products with better performance provided with excellent quality down filled up. It requires a minimum space for storage and carrying, providing ample inner air layers as inflated when using the sleeping bag, and best quality insulation performance for a comfortable sleeping space with its light weight. Being the insulation performance of sleeping bag sharply deteriorated smelling foul odor by sweat once it gets wet, it requires careful attention for use and storage. When the sleeping bag is contaminated, appropriate washing and laundry can be arranged.
The life spans of down type sleeping bags are known as about 20 years for goose feather and 10 years for duck feathers. The fill power, an index showing the elasticity (recovery performance) of down feathers, refers a measurement of inflation level for a certain specific time period upon engaging pressure on 1 ounce (28.35g) of down feathers. When the fill power goes above 650, the down feathers measured are classified as good quality. The down feathers of high fill power even with less amount of feather filled will demonstrate increased insulation performance owing to the increased air containing space.
The life spans (recovery performance) of down sleeping bags can go long by keeping them under unfolded condition for long period of storage. If such storage is not feasible, then keep the sleeping bag at a shaded and well ventilating area subject to no moisture under inflated condition as large as possible in sufficiently large non-woven fabric. When it gets wet, completely dry up and loosen the lumped down feathers by patting with palm of hand. The performance of down feather will get deteriorated by absorbing the fat and sweat from human body, so it is recommended to use a sleeping bag liner inside.
The artificial insulation materials used for sleeping bags are mostly of hollow fibers. The names of materials are called in many ways per each respective manufacturer’s interest. The hollow fiber is a chemical fiber manufactured with air gaps between sections of fabrics providing low specific gravity and high insulation effect. The artificial insulation materials have larger storage space requirement and relatively lower insulation property than those of down feathers, yet provide effectively strong withstanding performance against moisture and drying fast once they get wet. There will be no trouble of using the artificial type sleeping bag products for auto camping environment usually furnished with separate heating facility, in consideration of cost and maintenance convenience. Also in some cases, a hybrid type of sleeping bag combining the moisture vulnerable bottom part (underquilt) having trouble of forming sufficient air gaps because of human body weight as filled with artificial material and the top part (overquilt) with down feather for increased insulation performance can be useful.
Texture and Lining
The outshells of sleeping bags are usually made of polyester. Some premium high price tag products may use certain waterproof / moisture-proof materials such as gore-tex or wind stopper material. The linings are made of 100% polyester or fabrics mixing polyester and cotton together. The cotton well absorbing sweat or moisture provides a comfortable sleeping environment, but requiring careful attention for storage after use by completely drying it up. The sleeping bags are required to completely dry up not only the outside but also inside by turning inside out.