Choosing your hiking sleeping bag: down or synthetic?

The choice of a sleeping bag is a very important element if you want to enjoy a good night’s sleep whether in a camping, a star, a cave or something else. If you spend a bad night, I can guarantee that the next day may not be very funny.

In writing this, some bad nights come back to my mind. Either because of my idleness: “do not bother, the tent is very well there, we will not feel the stones” – in fact if, we felt them very well. Either because of my stupidity: “do not worry my protective cover protects well from the rain” – it is true if we do not take into account the runoff that soaked my sleeping bag. And sometimes because of a bad choice: “the little down will be perfect” – yes, perfect for being cold …

We will take care of laziness and stupidity another day and will first attack the choice of sleeping bag. This choice depends on several criteria – one of the most important is the nature of the lining(material inside the sleeping bag) which can be down or synthetic fibers.

For a better understanding of what follows, the operation of the lining must be designed as being similar to the double glazing. In the double glazing, it is not the glass that isolates, it is mainly the air trapped between the two panes. In the case of a sleeping bag, it is not so much the lining that isolates but above all the air trapped in this lining. The more air trapped in the lining, the more the sleeping bag will be “hot” – it will be said to isolate it. Indeed, a sleeping bag does not produce heat but it keeps the heat of your body by isolating it from the outside.

To help you choose between down and synthetic fibers, you need to know their characteristics, as well as their advantages and disadvantages.


Features of down

Down is mainly used for its ability to trap a large volume of air in a small amount of material. All the downs are different and the main characteristics influencing the quality of the down fillings are discussed below:

  • Type of down: down can come from geese or ducks. It should be noted that the quality of the goose down is superior to that of the duck down.
  • Quality of the packing: a packing is not entirely composed of down. Indeed, in order for the lining to be homogeneous, it always comprises a small percentage of feathers. This is represented by a down/plume ratio (90/10 means for example 90% down and 10% feathers). The higher the percentage of down is high over the quality of the trim is good.
  • Swelling power: the swelling power down or Fill Power (FP) is the volume occupied by one ounce of down. It is measured in cuin (cubic inches or cubic inches). Currently, the fluffs have a swelling power ranging from 550 to 900 cm. More this number is high, the higher the quality of down is good – because the more its light weight, compressibility (volume /weight ratio) and swelling are good. For a given down weight, her swelling power is high , the more insulation is good ./li>

Advantages and Disadvantages of Down Filling

  • Excellent insulation / weight ratio (“heat / weight”).
  • Good compressibility (good volume / weight ratio).
  • Good durability (long service life).
  • Breathable.
  • Recovers its swelling once dry.
  • Pleasant to sleep
  • Absorbs moisture.
  • Isolated less well once moist.
  • High price.
  • Drying difficult and long.
  • May cause allergies in some people.
  • If the sleeping bag breaks or tears, the down can escape.


Synthetic fibers

Characteristics of synthetic fibers

The indisputable advantage of synthetic fibers compared to down is that they offer good thermal insulation even when they are damp . This is why they are used in sleeping bags.

There is a multitude of trademarks and different concepts, the most well known being Primaloft , Polarguard, and Thermolite . Among all the synthetic fibers on the market, there are two main types – those that mimic the structure of down (Primaloft …) and others (Polarguard, Thermolite …).

  • Primaloft : it has a synthetic structure imitating natural down . Its swelling and compressibility properties are similar to those of down but it tends to lose its swelling more quickly over time.
  • Polarguard : it consists of a single synthetic fiber wound on itself. This forms a sort of cotton wool which is fairly solid and rigid , but not very compressible.
  • Thermolite : it consists of hollow fibers which ensure a good insulation / weight ratio . However, this ratio is lower than for most downs .

Advantages and disadvantages of synthetic fiber lining

  • Good resistance to moisture coming from inside and outside (perspiration, rain, etc.).
  • Isolated well, even wet or wet.
  • Cheap because easy to produce industrially.
  • Fast drying.
  • Easy washing.
  • Easy maintenance.
  • Poor insulation / weight ratio.
  • Poor compressibility (poor volume / weight ratio).
  • Average durability.
  • Loss of swelling with use.


A choice that depends on your practice

In the end, there is no incontestable winner between down and synthetic fibers – each filling has its advantages and disadvantages. It is up to you to find the winner depending on the conditions and the way you hike . Here are some things to help you choose according to your priorities:

  • Wet environment: If you bivouac in a very humid place , prefer a synthetic sleeping bag . This may be the case for nights under the stars, under a tarp (shelter formed of a tarpaulin), in the snow, etc. Sometimes condensation in a tent is even sufficient to wet a down. To overcome this problem , it is possible to use, for example, waterproof bivy bags or breathable membranes . In addition, some down fillings are treated to moderately resist moisture and some sleeping bags have an impermeable outer fabric.
  • Lightness: if lightness and compressibility are your first criteria, favor the down . For example, limiting the weight to the maximum is essential to spend a good time during treks or great hikes. A synthetic sleeping bag can offer the same insulation as a down sleeping bag but for greater weight and volume.
  • Price: if price is your main choice criterion, go for synthetic . This may be the case if you plan to use it once in a while to sleep in a refuge and on short hikes. But also consider investing in a down lining may be the most economical solution because the down has a longer life span .
  • Allergies: If you are allergic , it is not obvious because it seems that it depends on you as well as the type of down, treatment, creatures living in it, etc. The best is to test on a case by case basis. But if you want to be sure to avoid allergies, choose synthetic .
  • Maintenance : If you are a washing maniacor you are leaving for a long journey – and you need to wash your sleeping bag regularly – I recommend the synthetic which is much easier to maintain and dries faster .
  • Comfort: finally, if the comfort inside the sleeping bag is the most important element for you, the down should satisfy you because it is more pleasant than synthetic.

Once you have determined whether you need a down or synthetic sleeping bag, there are still some important criteria to study properly before you go to purchase. Stay in the corner , one of these days I might say more about how to choose your sleeping bag.

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