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How to choose your sleeping bag

There are so many different sleeping bag brands, models, shapes and temperatures of use that choosing a bag can sometimes be a bit tricky. It all depends on how you intend to use your sleeping bag. The following 3 criteria should be considered when selecting your bivouac companion.

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Temperature ranges :

Until quite recently, manufacturers indicated temperature ranges according to their own measurements, resulting in unreliable temperature range displays. With EN 13537 and EN 23537, sleeping bag operating temperatures have been harmonized and standardized.

Three temperatures are generally indicated on the label :

This is the temperature limit at which the user of the bag, curled up inside the sleeping bag, is at the limit of the sensation of cold (for a 70kg man and under normal conditions of use). This position is adopted to minimize the surface area of the body that loses heat;

1/ The "comfort" temperature :

This temperature is the limit at which a person can sleep in a relaxed position, e.g. on their back, without feeling cold (for a woman weighing 60kg);

2/ "Comfort limit" temperature :

This is the temperature at which the user, curled up inside the sleeping bag, is at the limit of feeling cold (for a 70kg man in normal conditions of use). This position is adopted to minimize the surface area of the body that loses heat;

3/ "Extreme" temperature :

This represents the temperature at which the risk of life-threatening hypothermia appears (determined for a woman weighing 60kg, curled up and in normal conditions of use).

The lining :

You have two choices when it comes to filling your bag :

1/ Down :

If you're looking for excellent insulation, minimum weight and high compression capacity, your choice is made: down has no rivals.

The filling is either goose down (the best quality) or duck down. The percentage of down and feathers is often indicated on the label. The higher the percentage of down, the better the quality of the bag.

The loft of the down is also measured in Cuin (Cubic inches). The higher this index, the better the down selection. At 800 Cuin, we're talking top-of-the-range.

Consumers who are sensitive to animal welfare sometimes choose to avoid down because of the mistreatment (raw feather removal) to which some geese and ducks are subjected. The private Responsible Down Standard (RDS) certification, which some brands promote, enables the origin of the feathers incorporated to be traced, the aim being to limit cruel treatment.

The main fault with down is its drastic loss of performance when damp. Some down is now treated to make it more resistant to moisture.

2/ Synthetic :

Synthetic filling is cheaper but performs less well than down. It is heavier and bulkier. Its greatest weakness is also its greatest strength: it absorbs very little moisture and dries more quickly than a feather down sleeping bag. And even when it does get damp, it stays warm and comfortable. Thanks to their moisture stability, polyester fibres retain heat better and don't clump together like feather down, making the synthetic sleeping bag an ideal ally for places with high ambient humidity.

Shape and locking system :

There are two types of sleeping bag :

1/ The sarcophagus :

Better suited to cooler temperatures, the sarcophagus is much more effective at dissipating heat. Its hood and shape, which narrows at the bottom of the legs, limit the cooling of the air inside.

2/ The blanket shape :

Suitable for warmer temperatures, this is much more comfortable and leaves plenty of room to move around.

Some bags have separate left and right zips, so you can combine them. Lovers will opt for two-seater bags, which are now very effective. For children, there are bags whose size can be varied. Ideal for keeping the bag with them as they grow up.

Important points to consider:

No matter how good your sleeping bag is, it only does half the job in keeping you comfortable at night.

To optimise protection from the cold, you need to choose a good mattress that will insulate the bag from the ground and considerably increase its performance. There are inflatable mattresses with reinforced thermal insulation.

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You can also use rucksack sheets that can be slipped into the rucksack to gain a few degrees, which is often important for your well-being. They also keep your sleeping bag cleaner and more efficient for longer.

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The underwear you wear has a major influence on your sleeping comfort.

Quality overpacks (waterproof and breathable) also help to prolong your sleeping bag's performance in wet conditions. Forget waterproof bags, you'll be wet after a night due to condensation and your natural perspiration.