Are you wondering how to choose a sleeping bag?
Our team of specialists prepared a detailed article which answers all your questions. Let us help you to have better knowledge in this area and choose a suitable sleeping bag.
We will try to explain to you how to choose a sleeping bag. However, due to the extensive and complexity of what is covered, it is not possible to explain everything in detail here, we tried to simplify this topic. If you are interested in more details, we are glad to answer your question by e-mail info@meboutdoor.com, we can offer all information and answer all your questions that would help you to make the right decision.
Which sleeping bag is the right one, Waterproof or Permeable?
There is no an ideal universal sleeping bag, so you simply need a different sleeping bag for the summer and for the winter. Windproof/waterproof quality and permeability are opposing qualities, meaning the higher windproof and waterproof quality, the lower permeability. And vice versa. The more permeable the fabric is, the less is it able to shelter from wind and water.
The most important principle when choosing a sleeping bag
We need to choose a sleeping bag that is warm enough according to the conditions in which we want to use it!
Based on financial potential we can choose a sleeping bag with the lowest volume after rolling up and lowest weight.
The most important quality that we are interested in above all are temperatures which the sleeping bag is appropriate for.
Thermal insulating qualities of a sleeping bag are defined by the thermal insulating ability of the insulation filling. It is in direct proportion to its specific thermal resistance and its volume. The amount of air molecules the thermal insulation filling is able to bind is the measure of its thermal insulating ability. Other qualities are only secondary and can more or less increase or decrease the specific thermal resistance – so called loft (fluffiness – ability to occupy as much volume as possible, simply how much is the sleeping bag able to blow up after being unpacked), way of sewing (sandwich, shingle), orientation of fibers in the fabric etc. The real insulating medium is not the filling itself, but the air it binds. Down or synthetic material only makes the space for the air to take up. That is why you will be cold in a huge and heavy sleeping bag made of a cheap, low quality insulating material, but you will be warmer in a thinner and lighter sleeping bag with high quality insulating material.
Basically, we can divide sleeping bags into four groups: ultra-summer, summer, three-seasonal and winter. If you often spend nights in open-air during the whole year, it is ideal to have all four types of sleeping bags. If you do not want so many sleeping bags, you need to make a compromise. For example, you can leave out an ultra-summer one and sweat sometimes in summer. Now you only have three. According to the principle “better warm than cold” you can leave out a summer sleeping bag and sleep in a three-seasonal from spring to autumn. Then you only need two types. And if you do not plan to sleep in freezing temperatures (where the winter sleeping bag is simply the best), a quality three-seasonal sleeping bag is completely sufficient.
Down or synthetic materials?
Down fillings
Down is a well-proven natural material with a great compressibility and shape stability. Most frequently used is the goose down. Considering cost, there is often used duck down to instead of goose down, but it offers lower isolating capacity and when damp there is smell a typical odor.
The thermal insulating quality of down depends on the ratio of more and less fine down. This is seen in the numbers – 90/10, 80/20 etc, meaning there is for example 90 % of the very fine down and 10 % of the less fine. Another quality characteristic is the fullness. It expresses total elasticity and expansibility – ability of feathers to occupy certain capacity. This quantity is measured in laboratories by internationally acknowledged method and it is denoted in cubic inches (cuin). Pure fine down (100/0) has about 950 to 1,000 cuin, mixture 90/10 approximately 650 cuin and 70/30 has 500 cuin.
Before, the only synonym for a warm sleeping bag was a down sleeping bag. But recently years, synthetic materials logically win over down in most customers.
Synthetic fillings
The advantage of a synthetic material is in the easy maintenance and minimum humidity absorption. A sleeping bag with synthetic insulation filling is therefore ideal for an universal use from spring to autumn. It also works well in winter, except the high-mountain dry conditions. It is the best choice whenever we do not want to spend time with regular treatment and maintenance. The biggest advantage is that we are able to dry it quickly and easily, it keeps most of its properties even when damp. You can wash this type of sleeping bag in a washing machine with a gentle program without degrading the insulating qualities (unlike down). Synthetic fibers are also the only good solution for people with allergies.
Finally, it is not possible to say that down is an obsolete material. Even the high quality and most expensive insulations do not come anywhere close to the weight and thermal insulation qualities of the goose or duck down. Who is going to bivouac in very dry freezing temperatures and needs to count each gram, he should choose a quality down sleeping bag.
Shell and Lining fabric
The main requirement concerning the inner fabric is the permeability. At the same time, the outer fabric should prevent an infiltration of humidity into the insulation filling, at least to some degree. The sleeping bag as a whole should have a sufficient permeability that allows the humidity to go through to the outer surface and spread out into the air. An average human sweats out approximately 0.5 to 1.5 liters of water in a form of water steam that has to get out. In the opposite case, it devaporates into water inside the sleeping bag leaving you damp or sweaty in the morning. If you feel sweaty in a relatively thin sleeping bag, it does not have to be very warm, but the shell fabric does not let out water steam. Damp insulation filling does not insulate as good as in dry conditions and the thermally insulating qualities of the sleeping bag get worse.
The fabric should be as light as possible to allow the best expansion of the insulating filling. The lining fabric should also be pleasant to touch. Down filling requires maximum demands on the used fabric. the fabric has to be dense enough so the down does not travel away from the chambers, but permeable enough so the water steam can go out. This is an impossible task so you sometimes sweat in your sleeping bag (do not mix up sweating with thermal comfort!) and other times down travels through the fabric.
Construction
The simplest sleeping bags with synthetic filling have one quilted layer of insulation. That is not the best idea in the three-seasonal sleeping bag.
The best solution is a “sandwich construction” with two or more independent layers.
Sometimes a “single construction” is used – mutually crossing belts are sewn to outer and inner fabric so sleeping bag make an impression of having more insulation. It is called a “false fluffiness”, because the specific thermal resistance of a sleeping bag is in direct proportion to the amount of insulating material. This type of construction is much more predisposed to a mechanical damage of the insulating fleece.
Temperatures
For many years, individual countries had their own standards. In 2002, the European Union created a European standard for sleeping bags (for measuring and calculation of usage temperatures).
Reliable producers or importers indicate these values. The slower ones state at least three values: maximum, comfort and extreme. If you do not find three values on a sleeping bag, but just one or two, it does not mean that the sleeping bag is bad. The author just tries to confuse the client. The client could think that an extreme temperature means the same as a comfort temperature… and the extreme temperature is absolutely not an allowable temperature, you may meet risk to spend the night in such sleeping bag.
All given values are valid only in ideal laboratory conditions and for a standard man or woman!
In reality, the usage conditions of the sleeping bag are extremely changeable. It is a countless combination of following factors:
temperature of the surrounding air
radiation temperature of the surrounding air
speed and whirling of air
humidity captured in the sleeping bag and the surrounding humidity
user’s clothing
user’s position in the sleeping bag
insulation between sleeping bag and ground and thermal insulation of the ground
compression of the sleeping bag by the weight and volume of its user
other than ideal surface and volume of the user and space of the sleeping bag ratio
Physiological reactions that are determined by the surrounding conditions and determine discomfort and risk of hypothermia are very variable according to the body temperature, cold hardiness, sex etc. Each of us has a different blood circulation, different metabolism and we sweat different amount of water during the night. These factors noticeably influence the subjective feelings of cold or warmth. In case of each individual, there can even appear changes during the time, e.g. due to fatigue, food, body situation, etc. They are influenced mainly by the climatic conditions, quality of the insulating underlay, physical shape, etc.
The perception of cold is always subjective! Temperature conditions of using are not only quantities resulting from the inner essence of a sleeping bag but it depends on the using conditions, individual person and their shape in the time of use.
Simple instructions based on this chapter:
Every time choose a sleeping bag with a sufficient warmth insulating reserve. Data on the tag do not mean that you will feel comfortable in any conditions – you would only feel comfortable in ideal laboratory conditions that you will not meet in reality. And how big reserve should you choose? It depends only on you and the conditions you can experience.
That means the temperature range of a sleeping bag is just an orientation value that results from a thermal insulation measurement of the sleeping bag and analysis of this measurement regarding temperature usage that helps to compare types of insulating materials and sleeping bags – in standardized conditions.
Size
The right size is very important. A small body will not heat an excessively large sleeping bag and vice versa – too small sleeping bag (that will not allow comfortable stretching of the body) compresses the insulating layer which then works less.
A sleeping bag should be moderately loose so the sleeper does not turn with the sleeping bag but only turns himself when moving. Producers of sleeping bags usually have two sizes regarding height of the figure.
Zipper
It’s better to choose brand zipper for sleeping bag, like YKK zipper. In addition, zipper should be covered with an inner belt that prevents the escaping of heat through the zipper.
Compression bag
Yes, a compression bag enables to compress the volume of the sleeping bag up to 40 % of its original volume but each of this compression lowers the lifespan of the insulation material, both synthetic and down. Fluffiness imperceptibly descends and the sleeping bag blows up less after unrolling.The longer and more often the sleeping bag is compressed, the worse.
Finally, hope that after reading this article you will know more or less how to compare different sleeping bags and choose the most suitable one!
