All you need to know about down

Expeditions shaped the beginning of Helsport as a company, and our current product range. Not many people know that although we started out mainly manufacturing camping products, this all changed in 1964.


We came into contact with Arne Næss Sr. who was planning a Norwegian climbing expedition to Tirich Mir in the Himalayas. This collaboration became the start of a complete restructuring of Helsport’s product offering and a new product designed specifically for the expedition — a revolutionary lightweight down sleeping bag.

Helsport has been working with down sleeping bags and clothing for almost 60 years, and despite impressive development in all areas of the hiking equipment business, down still has unique and remarkable insulation properties.

What are the benefits of down?

Down is a natural material with a fantastic warmth-to-weight ratio. This means that down is extremely light compared to how much warmth it generates. If having a light pack or pulk is your priority, then you definitely want to opt for a down sleeping bag.

In addition to their low weight, down sleeping bags can be compressed to take up very little space in your pack. You’ll get a warmer sleeping bag than with a synthetic bag with the same weight.

Down sleeping bags pack away very small, are lightweight, and comfortable to sleep in. It is important that you look after your down sleeping bag by drying and airing it out after use. Also, remember to store your sleeping bag in the storage bag that came with it, and not in the compression sack.

Down has a unique ability to regain its shape, meaning that a down sleeping bag that is well looked after can be used for many, many years.

Benefits of down:

  1. Highly compressible

  2. Lightweight

  3. Excellent warmth-to-weight ratio

  4. Very comfortable to sleep in

How does down insulate?

A down sleeping bag contains many compartments, all of which are filled with down. When the down expands and achieves optimum volume, space is created between the outer and inner material. Down has a complex structure that allows this space to bind and trap air generated by a person.

This means that the down and the surrounding material creates an efficient insulation layer around you, protecting you from the cold air outside the sleeping bag. In other words, your body heat helps to warm the sleeping bag and the protective layer between you and the cold air outside.

What if the sleeping bag gets wet?

Down loses its insulating properties if it gets wet, so our best tip is to keep your sleeping bag dry! We use water-repellent materials that keep moisture out, but if you know that your sleeping bag is likely to get wet on your trip, you might want to consider a synthetic sleeping bag instead.

Mixes and down quality

Our sleeping bags contain varying types of down quality; 90/10 duck down 650 FP, 90/10 goose down 750 FP and 90/10 goose down 800 FP. So, what do these figures mean? They indicate the fill power of the down used in the sleeping bag. The higher the fill power, the less down is needed in a sleeping bag to achieve the same temperature limit.

The actual figure represents how many cubic inches an ounce of down fills a cylinder with when a weighted piston compresses the down. 90/10 indicates the mix ratio of down to feathers. The greater the percentage of down, the smaller the pack size of the sleeping bag, which means better insulation. This is because down is better at trapping warm air than feathers.

Duck down vs goose down

The two types of down have virtually identical insulation properties. The main reason for using goose down is that it isn’t possible to achieve a fill power above 650 using duck down. If you need a sleeping bag that can be used in temperatures down to -15 °C, you should opt for duck down. Goose down is much more expensive than duck down and adds no benefit whatsoever in this type of sleeping bag.

However, if you require a winter sleeping bag that offers maximum insulation at a low weight, that’s when you should go for a goose down sleeping bag. Goose down has a complex structure with a high fill power and strength and generates optimum warmth.

Washing and maintenance

You down sleeping bag can last you many years if you look after it properly. When you return home from your trip, take the sleeping bag out of the compression sack to dry and air it. Once it has been aired and is completely dry, you can pack it away in the storage bag that it came with. This large bag stops the down being damaged by prolonged compression.

If you need to wash your sleeping bag, do so using a special detergent and a low spin. The washing machine must have a capacity of at least 7 kg. Remember to do up all the zips before washing. The best way of drying a sleeping bag is in a tumble-drier at a low heat, incorporating tennis/dryer balls in order to keep it “fluffy”.

If this is done correctly, the down can regain its natural fill power. Always read the sleeping bag’s washing instructions to be on the safe side.