"Down" is the fluffy inner feather that give birds their warmth. It is virtually impossible to get a 100% down product as small feathers also get into the mix. Standards are constantly improving but 80% down 20% feather (80/20) should be considered a minimum. Most manufacturers now use 90/10, though in reality it can often be higher than that - up to 94/6.
Fill Power relates to how fluffy the down is. Down that has come from older birds is usually 'fluffier'. The figures you see relate to the cubic inches of volume that one ounce of down will fill. Therefore the higher the number, the less down you need to create the same level of insulation. This means that for weight sensitive products such as those used in mountaineering and other sports where every gram counts, higher fill power is better.
500-550 is good, 550–750 is very good, and 750+ is excellent. Currently the highest fill power is about 900.
In jackets such as parkas that are traditionally heavier weight anyway, a lower fill power (500 – 600) is generally used as weight is not a primary concern.
European goose down is generally considered the best quality down, though duck down is also used. As down is essentially a by product of meat production, animal welfare is becoming progressively more important and many of our brands are now signed up to the Codex scheme that traces the origins of the down to ensure the birds are well looked after.
The one negative of down is its dislike of moisture which causes the down to clump up, causing a dramatic drop in insulating capacity.
To reduce the effect of moisture many products now feature "hydrophobic down". This is specially treated to repel water so it will remain effective for longer in wet conditions, and will also dry out and regain its maximum loft more quickly.
Down feathers often have pointed ends that can work through outer fabrics. The fabrics used by our brands are carefully selected to be as 'downproof' as possible to minimise this effect, though some 'migration' of the down will occur with most products as the fabric is punctured when it is sewn together.
If any down feathers begin to come out of your garmets, from the other side of the material, pinch the filling and gently pull apart the two sides of the material to pull the offending feather back in. If this can't be done, don't worry too much, the garmet won't suffer without it.
Some jackets such as parkas often have a waterproof outer shell, but many of the more technical mountain jackets use densely woven windproof, high breathability fabrics that are only water resistant but are very quick to dry. Whilst being resilient, these fabrics are generally very soft to the touch adding to the luxury feel of the down.
As down is a loose mix of individual pieces rather than a woven layer, the down has to be kept in place using baffles to prevent it all slumping to the bottom. Baffles are the stitching lines that are often seen running horizontally across a garment. 'Through stitched' baffles are the simplest and used on thinner garments meant for milder temperatures, other systems such as box baffles are used on thicker jackets and sub zero rated sleeping bags to maximise performance.
Many of our most popular brands use down, see The North Face Down Jackets, Rab Down Jackets, Mountain Equipment Down Jackets, Montane Down Jackets, Berghaus Down Jackets and Jack Wolfskin Down Jackets.