Sleeping bags – GearGuide


Beside being amazing and wonderful and thrilling, being active outdoors is also always intensive in a way, an tiring. A good nights’ sleep is essential to be able to enjoy the next day to the fullest.

The level of fatigue, how well hydrated and fed you are, temperature, weather, sleeping mat and obviously the sleeping bag itself, …… There are many factors that determine whether or not you have a comfortable night’s rest. There are factors you can’t control (a travel companion snoring like a pregnant bear) and some you can. Having the right sleeping bag is just one of them. In addition to taking into account the issues mentioned above, your choice for a sleeping bag will also be determined by the activity you are going to do and under what circumstances you are doing it.

Image: Mountain Equipment Xero 550 Slaapzak

For example, when you are going on a camping trip with a car or a motor, the weight and pack size of a sleeping bag will be less of a consideration than when you are doing multi-day hikes in the mountains where every gram you need to carry is one too much. If you are camping in a rainy area, it is important to consider what type of filling (down or synthetic) you choose for your sleeping bag.

To help you choose the right sleeping bag, some basic facts are explained.


  • Choosing a sleeping bag
  • How does a sleeping bag work?
  • Temperature
  • Insulation material
  • Form
  • EN 13537 standardization
  • Maintenance
  • Terminology

How to choose a sleeping bag

There are two questions you need to ask yourself. The answers to these two questions largely determine which sleeping bag is right for you.

At what temperature will you use the sleeping bag?

This is the first question you should ask yourself. Since the temperature can differ a bit, you should consider taking an average. If you buy a sleeping bag that has a reasonable bandwidth in the comfort temperature (see Temperature and EN 13537), it will not be necessary to pull clothes or open zippers so quickly when the temperatures are too much off average.

Note: Temperature means ambient temperature: when using a sleeping mat (which will provide insulation from cold ground temperatures) the ground temperature won’t be important to consider, rather the temperature above the sleeping mat.

When determining the desired Upper Limit and Comfort or Lower Limit, it is important to take into account if you are someone who feels cold quickly or not. Features like draft tubes, draft collars and hoods will prevent heat loss and are more important when the sleeping bag is used at low temperatures.

What are you going to do, what kind of vacation or activity?

During walking holidays weight and volume play an important role. The choice will probably turn to down as a liner. Synthetic may be preferable if there is a chance that the sleeping bag becomes wet or if you use it in humid areas. (see Insulation material)

If your nights are cold, you’ll probably be best served looking at a mummy model (see Form of the sleeping bag). A mummy model follows the contour of your body, which helps in preserving the warmth of your body.

How does a sleeping bag work?

Sleeping bags are meant to isolate and insulate: a sleeping bag prevents heat loss due to the presence of a layer of non-circulating air that your body from the cold environment (the air and the sleeping mat or the ground on which you lie). There are two layers of air actually: the one directly around your body, your micro climate, and the air that is trapped and insulated inside the sleeping bag itself.

The sleeping bag does not generate any heat by itself, it’s your body warmth that does all the hard work. This means that it is better to warm yourself up before crawling into your sleeping bag. If you are cold getting in, your body first has to produce the necessary heat. And lieing down it is more difficult to generate that warmth.

In order to hold the heat, sleeping bags often have constructions (compartements in the sleeping bag and / or a cord to close the sleeping bag) to ensure that the air moves as little as possible and that the filling is kept in place and distributed evenly over the sleeping bag.

Temperature & EN 13537 standardization

Sleeping bags have a standard, EN 13537, for the insulation value of the sleeping bag. This standard makes it possible to compare sleeping bags with each other. The standard consists of 4 temperature values (see EN 13537) whose comfort values are the most important of your choice.

These values should be set off to the ambient temperature of the space you are sleeping in. Inside a tent it will be 5 degrees celsius warmer than if you are sleeping under a tarp at -12.

EN 13537 standardization

This standard assigns four isolation values to a sleeping bag, expressed in a number of degrees / temperature. The insulation values are made clear by means of a diagram.


The values in this example indicate that a “normal” woman will have a comfortable night’s rest when the surrounding air has a temperature between + 22 ° C and + 4 ° C. A “normal” man will have a comfortable sleep when the ambient air temperature is between + 22 ° C and -1 ° C.

Furthermore, the diagram indicates that you can will feel quite cold between -1 ° C and -18 ° C, but there is still no serious risk of hypothermia setting in. If the temperature drops below -18 ° C then you could be in trouble.

Insulation material


The choice you need to make will always be between Down, Synthetic or a blend of the two. The choice you make here determines, among other things, the weight you need to take with you, the pack volume and the durability. Down is soft and small and you will find it for example on duck or geese, tucked under the outer layer of feathers they use for flying. On the animals down provides insulation as warm air is trapped between the tiny keratin filaments with tiny branch-like fibres. As down feathers are packed together, they hold on to each other resulting in thousands of tiny air chambers in which are can be trapped.

Down is very light.

Down has less volume because it can be easily compressed quite densely, and will reating its form after that compression.
Down retains its insulation value longer
Down is harvested from animals, especially ducks and geese. There are still too many examples of down being lived plucked from the animals, which is a horrible way to produce down. Most brands are becoming increasingly critical, looking for traceable down so that they can inform you of the way the down has been sourced. More and more you will see down being produced as a by-product of the meat industry, preferable from geese and duck that have been raised and treated in an ethical way.


With synthetic down you won’t need to consider that part of its sourcing. But it most often is a polyester type, and Polyester is a synthetic fiber made from coal, air, water, and petroleum. So there’s that. Synthetic fibers offer a less positive weight to warmth ratio than down and does not compress as easy. Meaning you will have slightly bulkier packs. It does not retain its original form as easy as down, so every time you pack it, and certainly when you store it for a longer time in its pack, it will lose a part of its insulation power. (better to store them rolled out or hanging loose somewhere).

Polyester is a cheaper material than down and it dries much faster. For trips to humid areas, this might be a good choice. When wet it does continue to isolate a bit, whereas down lumps together when wet and looses all its insulative properties.

There are sleeping bags that use down and synthetic materials together, working to prove the benefits of both products and trying to eliminate the negatives. Sometimes the fibers are mixed, sometimes the material is used in different zones of the sleeping bag: synthetic near the bottom and down most often applied to the area around your upper body where you need most of that warmth.


Most sleeping bags you will run into are mummy shaped, though there are models that resemble a peanut shape or even have a blanket shape. This choice is important because the more open space within the sleeping bag, the more air directly around your body needs to be warmed up. So a well fitting sleeping bag will be warm faster, but at the same time will give you less freedom to role around inside the sleeping bag to a new sleeping position. Restless sleepers will be less comfortable in a mummy shaped sleeping bag.

But if you get cold feet (literally) or cold toes quickly, will find they really need extra socks in a blanket shaped sleeping bag. So consider what the sweet spot between warmth and comfort is for you, what kind of sleeper you are and what will help you sleep best at night.

Maintenance & care

Washing a down sleeping bag

When washing, it is a matter of washing the down itself. This is why it is not easy to do the washing of a down sleeping bag at home; You need a large washing machine. Washing in a bathtub is possible (with a suitable detergent, usually available in outdoor sports).

Washing a synthetic sleeping bag

Synthetic sleeping bags can usually be washed in a large washing machine. Drying also takes a lot of time here and now it has to be regularly reversed.

Refilling a sleeping bag

Thin sleeping bags can be refilled. Wash first and then refill. Because washing improves the insulation value of the down, it may not be necessary to add extra down to the sleeping bag. So wash first, then test and then decide if you need to add more down.



Proper storage is of great importance:

  • Never put a sleeping bag in its compression pack for longer periods of time (it is better to store the sleeping bag in a designated bag)
  • Do not wait to get it out of the pack until the moment you want to go to sleep but take it out earlier, lay it in your tent and give it a chance to decompress. The volume will expand as the down or the synthetic fibres expand and it will provide better insulation against the cold.
  • If you pack the sleeping bag up, just stuff it in the compression pack; do not roll it up and you should certainly do not fold it. Leave the zipper open.
  • The use of inner sheet keeps the sleeping bag (down) clean. It will retain its insulation value longer. An inner sheet also adds some extra warmth.
  • Down feathers will sometimes stick through the sleeping bag, but do not pull them out. Rather try to pull them back (by pulling down on the other side of the sleeping bag).
  • Loss of down through time is very normal.