A Box-wall down jacket is one that utilises 'Box-wall' construction for it's baffles. Baffles are the pockets of space that are created between two layers of fabric which then hold the goose or duck down that is in your jacket. These chambers filled with down are how the jacket keeps you warm. Your body heat warms the air around it through radiating that heat, when you are wearing a down jacket the air that you are warming with your body heat is trapped by the down, creating a layer of warm air around you. The more loft a jacket has, the more air that can be trapped which is why the bigger, puffier down jackets, such as the Rab Positron Pro, are warmer than more low-profile down jackets, like Rab's Microlight Alpine Jacket.
Baffles can be built mainly in two ways 'Box-Wall' or 'Stitch-through', box-wall construction is the warmer of the two as it allows the down to loft more which more effectivley procides warmth, this results in fewer cold spots in the jacket. These horizontal compartments are designed to hold the down in place around the body and maximize the performance of the jacket - jackets using this method are quite often heavier and don't pack down as small as most jackets that use stitch-through construction due to more materials being used.
As you can imagine making fabric 'boxes' for the down rather than sewing through quilt style is a lot more work and is a lot more complicated to make. For this reason the majority of down jackets on the market are 'stitch through' and the few that are 'Box-Wall' are more expensive. The technology is usually reserved for the more demanding products such as high-mountain & expedition gear.
Stitch-through construction is the more common approach as it is easier and less time-consuming to produce for manufacturers; the outer material is stitched directly into the inner lining, separating the down in different baffles. This is less warm than box-wall because the down is pinched at the seams, reducing the optimum loft of the down, at the point of the seam the down cannot loft at all, this creates cold spots.
The benefits of using stitch-through baffles are that this method uses less fabric overall and is lighter than more complicated box baffle construction, it helps keep the price of the down jacket low too.
Stitch-through baffles are most suited to lightweight down jackets that are not designed for high-mountain and polar expedition use. This should be an indication of why you may only see box-wall construction on the very top end of the scale of down jackets. Out of Rab's wide range of down jackets they only have 5 models which use box-wall construction, including their everest-ready expedition suit.
So what are the main points that you should consider if you're thinking about getting a box-wall down jacket?
The new Positron Pro Down Jacket from Rab utilises box-wall technology to create an incredibly warm jacket for its weight. Complimenting that are these other essential features for a high-mountain down jacket:
Rab are experts in using down to create some of the best-performing insulation garments in the world. They have a long history of using the material in clothing and their sleeping bags to great effect. Out of their vast range of down jackets there are only five models which use box-wall construction; the Valiance Jacket uses bonded seams to create the box-wall baffles eleimnating the need for stitching. Add a waterproof Pertex Shield outer and you get a fully taped waterproof winter down jacket.
The new Positron Pro jacket uses 300g of 800+ fill power hydrophobic down to create a water-resistant, winter jacket for climbers and backpackers. Available in Mens & Womens specific fit. A superlight shell fabric aids in weight and packability.
They then have another new jacket which is the Expedition 7000. This is designed for those who are attempting 6000-7000m summits. They have balanced warmth, weight and weather-protection in this jacket by using a lightweight shell material to aid the down in lofting, whilst still having a good DWR and strength to the fabric.
The warmest Rab jacket in our range is the Batura, this beast uses 450g of 800 fill power down alongside a fully waterproof Pertex Shield shell fabric to create a jacket built to withstand almost any conditions. A medium size in this jackets weighs in at 1258g, this is currently our heaviest down jacket.
Rab also make a full expedition suit which uses box-wall down baffles.
We are giving away a Rab Positron Jacket - one of Rab's new box-wall down jackets for Winter 2018. Answer the question below to put yourself in for a chance to win. Terms & conditions apply.
In the late Seventies, a revolution was brewing in Britain’s industrial heartland. Confronted with strikes, power cuts and a three day working week, local people responded with characteristic ingenuity and grit – abandoning the factory floor in increasing numbers and escaping into the pristine landscapes of the surrounding Peak District.
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