Strange name, big price tag - so is the ISPO Gold award-winning Kjus Hydro_Bot worth it? Alf Alderson puts the £1,299 jacket through its paces  

Most of us will have experienced that horrible cold, clammy feeling of our base layers sticking to our skin after a tough skin up or a hard descent on a warm spring day. It is, of course, the result of our layering system being unable to wick away sweat more rapidly than we're producing it, and the resulting moisture cooling against our skin is uncomfortable at best, dangerous at worst.

The Kjus 7Sphere Hydro_Bot jacket claims to put an end to this with the revolutionary technology that's incorporated into the garment. In short, this prevents post-activity chill by actively pumping sweat away from the skin to the outside of the jacket when an electrical pulse is applied.

It's a process called 'electro-osmosis,' and works via two panels strategically located on the high-sweat zone at the back of the jacket. A membrane made up of trillions of pores per square metre is surrounded by conductive fabric which, on the application of a small electrical pulse from an integrated control unit, turns the pores turn into 'micro-pumps', actively pumping sweat away from the body and out of the jacket quickly and efficiently. The system operates at the push of a button on the control unit or via Bluetooth from an iPhone and Android compatible app.

Kjus says that this system is up to ten times more effective than regular breathable membranes, and the more you sweat, the more it transports that sweat away from your body, being the first ever garment to be able to match human perspiration rates in terms of breathability.

Kjus claims that Hydro_Bot  technology not only boosts the enjoyment factor of your skiing, but also the performance factor, by allowing your body to invest minimal energy on thermoregulation and focus on providing maximum energy for skiing. In an emergency situation, such as being immobilised on the slopes in sub-zero temperatures after an injury, a system that helps to reduce or even prevent the risk of hypothermia (which is obviously exacerbated if you have cold, wet material next to the skin) could literally be a lifesaver.

So what else you get for one pence short of £1,300? The design is stylish and understated, as you might expect from Kjus, with the Hydro_Bot coming in just one colour (black) and at present only being available in a man's style. The outer fabric has four-way stretch and a smooth, tactile finish, but the jacket is heavier than you might expect thanks to the Hydro_Bot panels, although no heavier than an insulated ski jacket.


All the essential features are incorporated into the design including a removable, adjustable hood, two chest and hand pockets with waterproof zips and a ski pass pocket. There are two inner stash pockets, a neck warmer, detachable money pocket and goggle cloth, small lower arm zippered vents and a detachable powder skirt plus adjustable cuffs and hem.

The Hydro_Bot control unit is little bigger than a credit card and clips into a small internal pocket; it is charged via a USB lead, so you'll need to ensure you have a device you can connect this to when you're on your ski holiday. It can be operated via a push button or through an app on your phone, saving you time fiddling around inside your jacket. One charge provides up to 16 hours of power for the unit.

In addition, there's a '7Sphere' multi-layer ventilation system on the chest, designed to be worn in conjunction with either a Kjus 7Sphere mid-layer (which I used) or synthetic/wool blend base for the best wicking performance from the system.

I tried the jacket out on a humid August day with an air temperature of 21C, hiking up a steep slope behind my home in Les Arcs until I was sweating like a fat lad. The Hydro_Bot system won't actually stop you sweating, of course!

I then stopped for a rest to wait and see whether the usual cold, clammy feeling developed on my back from cooling sweat trapped against my skin. I was perspiring, of that there was no doubt, but even after several minutes the sweat on my back hadn't cooled and was, in fact, starting to dissipate and dry out. Presumably due to electro-osmosis from the Hydro_Bot system.

Sure, I wasn't skiing (it was August, after all) but my hike was not dissimilar to skinning up. In fact, I regularly skin up this same slope in winter – and since the Hydro_Bot system is specifically designed to work at its best in sub-zero temperatures (when the performance of regular breathable membranes drops significantly) it does seem that here we have a definite – if expensive – alternative to the breathable membranes that skiers, hikers, bikers and other outdoor types have been using in one form or another for the last 40 years.

The skiers and boarders who might most benefit from this new technology are, of course, tourers and freeriders. And here lies my only reservation (other than the price) with the Kjus 7Sphere Hydro_Bot: it's not especially light or packable, and that may reduce its appeal to those markets, for whom lightness and packability are as essential as breathability.

But if money is no object and sweat-free comfort is high on your list of priorities, the Kjus 7Sphere Hydro_Bot is a really neat bit of kit. It also looks great, is well-made and has all the features you're likely to need in a ski jacket.

But it does cost the price of a decent ski holiday...

FOR Prevents that cold, clammy feeling from cooling sweat, looks good and helps improve your ski performance.

AGAINST Very expensive. Possibly too heavy and bulky for freeriders and ski tourers.

Find out more about the jacket on the KJUS website here.