Berghaus’s Thindown insulation promises hot performance benefits, but does it make the Aonach hot property for hillwalkers?
Material Insulation Thindown (750 fill power down/synthetic mix), shell 88% polyester, 12% elastane
Weight 557g (size L)
Staying warm in winter is easy in principle. You just add loads of extra layers of clothing that trap extra pockets of warm air against the body, right? Wrong! If you just add more layers you end up with a bulk of clothing that limits easy movement and reduces breathability. Then there is the weight of all those layers and also their financial cost. Instead what is needed is just one layer that offers the right amount of insulation in the lightest form, with the most practical design and at the lowest price possible. Great in principle.
Enter Thindown, the new form of insulation from Berghaus that is used in the Aonach jacket. During manufacturing down is fused with polyester to create an interlocked stable sheet of Thindown insulation. This insulation is said to be 30% warmer than polyester insulation alone, as well as being more compressible and more durable, while also retaining its loft and warmth much longer than standard polyester.
As Thindown is a stable sheet of material it is much easier to hold in place within a jacket, so there is less need for the complex array of stitched baffles used on conventional down jackets. Also there’s no need to use fabrics that are designed to prevent pieces of down escaping, such as tightly woven nylons, leaving the way clear for more open-weave materials that allow for far greater levels of airflow and breathability. Berghaus claims the shell material on the Aonach is 50 times more breathable than a standard down jacket, and describes the Aonach as ‘the world’s first truly breathable down garment’.
As the Aonach is so breathable, Berghaus also claims it can be worn under a waterproof hardshell jacket without any build-up of condensation. It’s also warmer than a fleece, while stretch fabrics have been used to enhance the fit and freedom of movement. If that wasn’t enough the Aonach also uses 50% recycled materials and over 90% of the materials are Bluesign approved for their environmental performance.
I took the Aonach on the hill at the start of autumn, and wore it under a waterproof jacket to block out the wind while heading up steep slopes on the Lakeland fells. It was immediately apparent the condensation you’d normally expect when wearing a synthetic or down insulation jacket under a waterproof did not materialise. The tricky part of the equation though, is the Aonach is pretty warm. It feels like you are wearing a thick fleece, or even two thin fleeces, so I found the Aonach just too hot for a lot of hillwalks. If you use the Aonach as an extra layer to throw on when you stop walking then its breathability benefit is less useful, as you won’t get condensation when resting anyway. So this means the Aonach is going to be best for really cold weather when you are still moving, making it more of a go-to jacket for those really cold winter days when you want something extra to throw on while walking, such as a second fleece or thin synthetic jacket or gilet.
The Aonach weighs 557g (size L), so is a similar weight to a good general fleece jacket. There are pure down jackets that are lighter though. For a jacket designed to keep you warm when being active, it is surprising there is no hem drawcord, no hood drawcords and no cuff Velcro tabs to lock out draughts, and I definitely needed a closer fit at the hem. Also, if this is designed to be worn while walking then it needs a layout of pockets that allow easier access while wearing rucksack belts, and other jackets are better in this area.
Finally the thin stretchy polyester outer is not the most durable, so if wearing this for rougher movement over rock then care is needed to prevent it snagging. I noticed the cuff area is a little baggy and already starting to show signs of abrasion from the rocks I had scrambled over.
The Aonach costs £200 but you could buy a good fleece jacket for £100, or a thin synthetic insulated jacket or warm down jacket for £150. A really light and warm down jacket, meanwhile, would set you back around £270. So you need to be keen on the Aonach’s warmth, weight and breathability ratio to warrant the price tag then.
So is the Aonach right for your needs? For me, its ideal for those really cold hillwalks when a waterproof jacket, fleece jacket and base layer just aren’t enough, which means Scotland in winter and occasional days in England and Wales when the temperature plummets. But I’d like some design tweaks to make it perfect for use while walking uphill, rather than for just sitting on the summit and enjoying the view.
Berghaus’s Thindown is a great new material for backpackers, hillwalkers and mountaineers who need more breathable insulation when moving through freezing conditions, but for active use some design details could be better in the Aonach jacket.
In use 4/5
Value for money 3/5
OVERALL SCORE 88%
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