If you intend to spend more time in nature, one of the most important items of equipment you need to prepare is the sleeping bag. In case you haven't got one yet, this article will help you choose the right one for you.
The first and most important thing you need to know about the sleeping bag to make the right choice and to use it properly is the principle by which it works. The sleeping bag practically does not create heat. Its purpose is to isolate the heat that your body releases. Your body heats the air in the space between it and the walls of the bag, and the task of the sleeping bag is to limit the loss of this heat to the environment. The insulating properties of a sleeping bag are determined by two main factors - its shape and the material of which it is made.
Before focusing on form and material, we will mention another factor that must be taken into account when choosing a sleeping bag. Namely - under what conditions it will be used. This includes not only the season and weather conditions - whether it is summer, winter or all-season, whether it will be used in humid or dry environment. It also includes whether it will be used for transitions (and should therefore be compact and lightweight when folded) or when camping when luggage will be carried by car and accordingly, we can afford a larger and heavier bag.
Returning to the form, we can distinguish 3 types of sleeping bags - rectangular (also called "envelope"), type "mummy" and cylindrical (hybrid variant between the first two).
The rectangular type of sleeping bags are best suited for warm weather because the design features - the large spaces around the torso, legs and soles - mean that the body will need to release more heat to keep them warm. And again, because of the shape, it is easier to release heat into the environment through unpaid space. With these sacks, the zipper opens completely and they can become a double-sized blanket. These bags use a larger amount of fabric, making them heavier and heavier.
The "mummy" bag follows the curves of the body. In this construction, there is very little free air space around the body. It best retains heat and is used for sacks in colder weather. Also, the zipper in this model does not usually open completely to the lower end, leaving some space for the legs. When fastened, once inside the bag, the opening forms a well insulated hood. Usually, a tightening eraser is also used to help the hood fit snugly around the face and minimize the possibility of heated air escaping from the sack. In this model, weight and volume depend on the amount and type of insulation materials used.
The cylindrical type is a kind of hybrid between the first two models. Its shape follows that of the body, but the free space that remains is larger than that of the "mummy" sacks. This model usually has a hood or extension that provides some protection and isolation of the head. It may be in combination with a fastener, but it may be missing. This type of sacks are usually designed to be used mainly in the spring or autumn time.
There are two main types of materials that are used in making sleeping bags to achieve the insulating effect. The first is natural stuffing - duck or goose down. The second option for insulation is synthetic fibers.
The down is made up of very fine feathers and fibrous structures that are tucked under ducks and geese. The amount of air they can hold in comparison to their weight makes them very effective insulators. In addition, their weight is extremely low. The properties of this material not only make lighter sacks lighter, but also allow them to compress to a very small and compact size. Another big plus of the downy sacks is that they not only retain excellent heat, but the heat / weight ratio is better than synthetic ones. Their lives are also longer. However, these sacks are much more expensive. They also require special maintenance to retain their properties. And the fluff has a big drawback - if it gets wet, it can't be used until it's completely dry. Sacks are now available in which the down is treated with special hydrophobic substances to make it more moisture resistant. But this raises the price, and yet, hydrophobic fluff does not perform as well as synthetic insulation in the presence of moisture.
The synthetic stuffing of sleeping bags is made up of long micro filaments (bundles) combined in bundles. These threads are usually hollow - on the one hand to reduce their weight and on the other to hold more air. The big plus of these fabrics is that they retain their insulating properties even when wet. They also dry extremely fast. In addition, they do not pose a risk to people with allergies. Synthetic sacks are generally bulkier and heavier, but the refinement of these fibers is ongoing. Maintaining these bags is also easier. Their insulating properties and their life are smaller than those of the downy, but at the same time their prices are lower.
The temperature of the sleeping bag can give you an idea of what time is right. To explain you better, we'll briefly explain them.
Comfort temperature - it provides the optimum conditions for you to feel good in your sleeping bag. You should always refer to it as a benchmark when buying a bag.
Extreme temperature (risk limit) - it shows the absolute limit of the sleeping bag. It is very important to know that it should only be used for information in order to present the bag in a critical situation. In no case should you take it as a basis for normal use. This indicator indicates the temperature at which you can stay in the bag for up to six hours without the risk of hypothermia.
The comfort limit hints at the temperature at which one can sleep for up to eight hours without waking up in the cold.