Polartec announced it's new 'puffy insulation alternative' around a year ago, but it's only now that it's starting to appear in the shops and we've just reviewed jackets from Rab and Marmot using the new Alpha material.
What's it all about? In simple terms, it's something a bit like a traditional synthetic insulation technology - PrimaLoft is probably the best known - but designed to be breathable enough to be worn on the move when you're kicking out lots of heat, sweat and steam...
If you look at the image above, you can see it's a sort of sandwich of fabrics rather than a jumble of fibres trying to imitate down and as a result, says Polartec, Alpha is no less than twice as breathable and 60% quicker drying. In addition, it gives brands the choice of using more breathable face and liner fabrics to up breathability.
The downside is that it's less outright warm than synthetics of similar weight and bulk, but that's missing the point. You're supposed to wear this stuff on the move, in the cold, not carry it around to just wear when stopped or on belay. Simple huh?
To look at the jackets just scroll down the page or follow the links below and jump straight to each product.
Rab Strata Hoodie - £150 / 430g
Rab's new Strata is a simple, no-frills, 100% Alpha hooded jacket complete with a hood that sits under or over a helmet, twin hand-warmer pockets, adjustable hem and hood and simple stretch cuffs. It's built slim and simple.
It really is significantly more breathable than conventional synthetic puffies, which makes it brilliant for active use in cold conditions where you want warmth and weather protection but without the boil in the bag factor. Nothing overly clever or complicated, though the lining fabric is zoned for improved breathability in the core.
There's very little to about really, though it's not as warm as comparable traditional synthetic tops thanks to less air trapping capability and a shell fabric that'd deliberately not 100% windproof.
So far we're dead impressed with Polartec's Alpha insulation precisely because it's not really like a traditional synthetic puffy insulation system at all. It's almost as warm and almost as weather resistant, but - and this is the crucial plus point - you can wear it on the move without boiling alive, something we're looking forward to this winter, when we reckon the simple, slim design of the Strata should be ideal from everything from cold weather mountain walking through to sub-zero biking. Simply brilliant.
Marmot Alpha Pro Jacket - 370g / £175
The Alpha Pro's an odd platypus of a jacket with a mix of Polartec Alpha with a windproof Pertex Quantumn shell fabric in the torso, Power Dry High Efficiency under the arms and side and on the inner sleeves and PowerStretch elsewhere with somewhat Marmite results that you'll either love or just not get at all.
It has a close fleece-like fit and feel but with added weather protection and insulation for your core, and doubles as an outer or mid layer. However, if you don't move fast and run hot, you'll wonder why your arms are feeling chilly.
An odd platypus of a jacket for sure. It's not fleece, it's not synthetic puffy insulation and it's not quite an insulated gilet either - instead it sits somewhere in the middle of a three-way fabric dust-up, but here's the thing, in the right condition, with the right wearer, it works incredibly well. All you have to decide is whether it'll suit you or not - if it does, you'll love it.
In a way, the whole 'puffy insulation' thing is a little confusing, it's better to think of Alpha as warm stuff for moving fast in when the going gets cold rather than as a more traditional belay-type jacket that you just sling on for stops. It will do that as well, but if that's what you really want, traditional synthetics and down are lighter and warmer for the weight.
Where Alpha really scores is in a cracking mix of insulation and breathability. Of the two jackets we've tested, the Rab is a no-nonsense, cold-weather all-rounder that we really like. Meanwhile the Marmot is more, erm, Marmite in nature. If you run hot or mainly wear it as a mid-layer it makes sense, but we suspect a lot of slower moving folk won't really get it at all.
Last but not least, we really liked the Polartec Alpha gilet unbranded seeding garment. It's a bit like the Marmot, but without the sleeves and less bulky as a result. Rab's Strata Vest is a similar beast and something we'd definitely look at if you like the idea of the Marmot jacket, but just want the insulated torso bit.