Down insulated clothing. An updated classic with unbeatable properties

Down insulated clothing has had its ups and downs in the world of mountaineering clothing. But over the past few years it's made a comeback, thanks to the evolutionary designs, which have notably increased performance. There is no doubt that down insulation is way ahead of synthetics as far as the combination of warmth, weight & compression are concerned.

An insulated Arc'teryx jacket, for the extreme cold
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Down insulated garments, jackets in particular, are renowned for their low weight but are also very puffy which tends to limit freedom of movement during active sports. Down jackets are ideal for low-active sports or for keeping warm after activity in extreme climates and for this they remain unbeatable. Just think about expedition suits.

However a few years ago, new designs began to appear in the stores. These were more athletic, with a closer fit and were less puffy so that they could be used as a mid-layer, instead of a polar fleece. But as often happens, it wasn't long before climbers, mountaineers & skiers found new uses, which led to a resurge of down insulated clothing for mountain sports.

The climbers were the first to realize the advantages of these jackets: feather-weight and so compressible they pack into the smallest space in your pack, which means you'll never have to leave it behind and activities such as belaying becomes much more pleasant thanks to the increased thermal capacity compared to synthetic garments of the same weight.

Belaying in a down insulated jacket. Very warm, minimum weight and highly packable
Mountaineers soon began to use them too, and this new design meant that in certain temperatures they gave great performance during activity, both as a mid and outer layer.

The reaction by manufacturers was immediate and they began to research how to achieve a more active cut to make it even more functional, improve the distribution of the down with the baffle design and reduce the weight of the outer fabric that holds it in.

Today, the properties, style and comfort of down garments means they are not only used for a wide range of outdoor activities, but also as daily wear around town.

Examples of these jackets are the Arc'teryx Cerium LT Hoodie, Rab Microlight Alpine Jacket and The North Face Quince Hooded Jacket.

All thermal garments are based on the same principle: the materials retain warmth produced by the body, preventing it from escaping and in this way providing warmth. But here is where the similarities between the materials end.

Think about a normal jacket: it gives warmth, but the materials don't compress and so it always takes up the same room. This has two disadvantages for use outdoors, in the mountains or in snow: the thickness required to retain warmth is fixed, the garment is heavy and more uncomfortable and it takes up a lot of room, which makes it difficult to carry. These garments are not compressible.

Down and synthetic fibre garments are both in the compressible category and the advantages are numerous: if the garment can be compressed when not in use, it requires less material, it weighs less, it is more flexible and it takes up less room in your pack. Yet it provides just as much warmth because it expands and retains the same body heat.

But fibre doesn't expand as much as down. This is because, rather than the 3D shape of a down cluster, which traps a lot of heat, the continuous filament composition of fibre is flatter and more felt-like, which traps less heat and is not as breathable.

Feather down. The 3D highly expandable cluster groups naturally

Primaloft. It expands less and the fibres are joined, creating a barrier
This season, however, Primaloft & The North Face have have launched what could be considered as the first synthetic material that, as a whole, functions with the 3D expandable properties of feather down: Thermoball. Also referred to as synthetic down, Thermoball is said to be the equivalent of 650 to 750 down and yet boasts all the advantages of fibre as far as standing up to humidity is concerned.

Thermoball Hoodie Jacket, The North Face
As we've already mentioned, thermal garments work by retaining the warmth produced by your own body. Down retains this heat slightly differently compared to other garments, which tend to create a protective barrier, as it creates a 3 dimensional network that contains warm air. For this reason the greater its capacity to expand, the more heat it retains.

This expansion capacity of down is measured in Cuins (cubic inches) and with standard laboratory tests. The higher the Cuin number, the greater warmth capacity at the same weight and volume.

The cuin mainly depends on the quality of the down. Down is the soft, small feather found underneath the larger feathers that give the bird warmth and this down doesn't have a quill. The quantity of down, in relation to feathers in a garment varies and the highest quality down insulation is expressed as 90/10 (100g of padding has 90g down), but 80 and 75 are also a good choice.

Using the same quantity and weight of down, the higher the cuin, the higher its loft or volume Photo: Allied Feather & Down, Arc'teryx
Another advantage of down is its softness, which adapts very well to the shape of the body. This is something brands have also picked up on and the latest garments are much more athletic and ergonomically comfortable. Thanks to the almost ethereal weight of down and its capacity to adapt to body movement, few garments are able to provide as much comfort.

Baffles are also an essential part of the design. These compartments may sometimes seem arbitrarily placed and more of a fashion statement, but the aim of baffles is to eliminate cold spots and maximize the properties of the down, as well as offer the right amount of warmth for each zone.

The outer fabric that contains the down is also important, both because it improves the properties of the garment and because, if it is good, it lightens the general weight and has a smooth and soft feel.

These jackets are a far cry from the older designs, are truly R+D innovations that optimise the properties to the maximum.

Rab down jacket
So far, down may seem to have just advantages. But unfortunately this is not the case. Down has a great enemy: Humidity. When wet, down loses nearly all of its properties; wet fibre on the other hand is still able to partly retain warmth.

This conditions the use of down to certain situations: if the activity is very athletic and causes perspiration, this body moisture will affect the down and reduce its thermal capacity and the same thing happens if worn as an outer layer in wet weather.

For this reason, down garments are especially indicated for the most extreme conditions: very cold and dry climates, with or without precipitation, as long as it's cold enough for snow, not rain. They're ideal for resting after activity, for belaying or for activities that don't involve over-heating.

In this sense, synthetic fibre insulation is more versatile. But in general, few thermal garments function very well when wet; which is why waterproof and breathable shell jackets are important.

Very cold and dry weather. Ideal for down. Courtesy of Haglöfs
Each brand has applied its own solution to this problem with humidity. Rab and The North Face tend to use down that has been hydrophobically treated to minimise the problem as far as possible.

Arc'teryx believes that this treatment shortens the life of down garments (which can last for many years with the right care), and that the results are more negative than positive. For this reason they have opted for an intelligent hybrid system, where the areas most exposed to humidity, be it from perspiration or rain, are filled with the latest synthetic fibre while the rest is filled with down.

Down has been a questionable form of insulation until some years ago, because of the way it was plucked from the birds and the conditions they were kept in; on one hand, the down was plucked from live animals, as it was considered to be better quality; and on the other, some of the down came from animals that were force-fed for Foie Gras Pâté.

However, since then, the top brands have taken measures and have formed the OIA Sustainability Working Group and European Outdoor Group; two groups that have managed to obtain and guarantee the traceability of the materials used by its members, so that the down comes only from sub-products and never from live animals and adequate living conditions are also guaranteed. Most brands refuse to use down which comes from Asia, as it is difficult to trace and all the brands selling products at Barrabes have signed the group's international agreements and use down which comes from small farms in Central Europe, which are certified to guarantee the down complies with the required ethical standards.

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