Down or synthetic filling

Down or synthetic filling

Sleeping bags can be divided into two types depending on the type of filling they have: down or synthetic. Both materials have their respective strengths and weaknesses and which is best depends on how you will be using the sleeping bag. Down has long been the most popular alternative among backpackers, but as synthetic fillings have improved and become more ‘down-like’, they have become an interesting alternative.

Down – light and packs well

Down is the natural choice when weight and volume are of high priority, such as when trekking. The material provides the most insulation relative to weight; it can be packed down into a small volume and therefore takes less space in your backpack. On the other hand, down is more sensitive to moisture and loses a lot of its insulating capacity when it becomes damp. It is therefore important that you keep your down sleeping bag as dry as possible, both when using it and when it is packed. Another downside is that down costs a little more.

Synthetic – withstands heat

Synthetic is a good option when you spend a lot of time in damp environments, e.g. when canoeing. Synthetic is not as sensitive as down and the fibres are able to regain their shape even after long-term use. It also withstands a certain amount of moisture without a dramatic loss of insulation capacity. The sleeping bags can be washed and the price is slightly lower. One disadvantage is that synthetic weighs a little more and takes up more space in your pack. It also offers poorer insulation than a down sleeping bag of the same weight.

More about Fjällräven’s filling materials

The down quality is classified using a fill power which is stated in cuin (cubic inches) and measures the tog rating of the down, or its ‘fluffiness’. The higher the fill power, the finer the down and the higher the insulation capacity. A fill power of between 400 and 450 cuin is considered to be of medium quality, 500–550 cuin is considered good, 550–750 cuin is very good and 750+ is exceptional.

The down in Fjällräven’s sleeping bags is high quality, carefully checked and ethically produced. Read more about the down process on the pages relating to our Responsibility towards animals.

We use Supreme Microloft in our sleeping bags, which is one of the leading synthetic fillings on the market. It is a combination of fine and somewhat thicker silicone-treated microfibres that fill the sleeping bag with insulating air, thus using the same principle as down sleeping bags. The synthetic fibres are shaped to give a comfortable fluffiness and to regain their shape well after being compressed.