If you want the most warmth per gramme of insulation in clothing or sleeping bags, then down still rules the roost - or wherever it is that geese crash out anyway. The stuff simply lofts better and packs smaller than any alternative and while are downsides, ooops, it doesn't like coming into contact with water for example, for cold, dry conditions it's hard to beat.
We've checked out seven top lightweight down jackets from Berghaus, Rab, The North Face, Mountain Hardwear, Columbia and Alpkit to help you choose, plus here are basics to guide you along the way.
Scroll down the page through the jackets or jump to your favourite brand via the links below.
Alpkit Filo Jacket - £95 / 530g
You can argue that at 530g for a medium, Alpkit's Filo isn't that light and in ultimate terms it isn't, but it's not exactly heavy either after a 20% weight cut last year brought in a new fabric that's both lighter than before and allows the down to loft more effectively.
The result is a jacket that's decently warm with bundles of loft, looks great and has a distinctive drop-tail for added, erm, tail warmth. Sure the 600+ fill power down may not be quite as high spec as the opposition, but there's enough of it to keep you warm and comfortable in proper winter conditions. It has a hood too, not in pic because it's detachable.
It's brilliant value for money, but amazingly the spec and performance are still excellent. If you're on a tight budget and aren't obsessed with gramme counting, it's hard to see past the Alpkit Filo. Bargain.
More info at www.alpkit.com.
Berghaus Ilam Jacket - £240 / 293g
The new Ilam lightweight down jacket from Berghaus isn't quite as light as the Ghost Whisperer, but we reckon it's slightly warmer. It uses an interesting construction with zoned baffles, so there are thinner areas under the arms, but more extensive down on the main torso.
The Ilam's real trump card is the water-repellent, hydrophobic down sat inside the Pertex Quantum GL baffles. We used last year's version in the Asgard Hybrid Jacket and found it both sustained loft when wet and dried out faster and more effectively than normal down without any tennis ball shenanigans in the drier.
It would make a brilliant lightweight climbing, trekking or backpacking jacket, but the hydrophobic down should make it that bit more resistant to damp UK conditions and partly justifies the £240 price-tag.
Not quite as light as some, but the hydrophobic down is a real advantage in the damp UK and it's nicely cut too.
More at www.berghaus.com.
Columbia Powerfly Down Jacket - £160 / 397g
Columbia's Powerfly Jacket would be a nice, but unremarkable microbaffled down jacket were it not for one thing, the shiny, metallic, Omniheat lining, which the brand says makes it around 20% more effective - in very simple terms, it works on space blanket principles by reflecting heat back inwards.
Like the Rab Microlight series, it's more of a three-season sort of jacket and it's not remarkably light - the Diez and the Infinity are only slight heavier, but a lot warmer - but one thing it does have going for it, is the Omniheat lining. It seems to mean the jacket warms up slightly slower than we'd expect, but once it's up to temperature, it's a little warmer than it ought to be.
But as a cool to cold and dry conditions, stashable insulation layer, it seems to be right on the money. Talking of which, the price is a steep-ish £160.
More at www.columbia.com.
Mountain Hardwear Ghost Whisperer Hooded Down Jacket - £230 / 207g
Dubbed the world's 'lightest, fully featured down jacket' by MHW, the Ghost Whisperer weighs an incredibly light 207g for a medium thanks to a combination of 850+ high loft down and ridiculously fine and light, semi-translucent 7D x 10D rip-stop fabric, which is exclusive to MHW.
All that and it has hand-warmer pockets, an adjustable hood and hem too. Pack size - it folds into its own pockets - is reassuringly tiny and the clincher is that it's still surprisingly warm. Ideal for minimalist alpinists - Ueli Steck helped develop it - and ultra-lightweight backpackers in cold, dry conditions.
The only downside is the lack of ultimate warmth - you may have to suffer occasionally - and the stinging £230 price tag. But if lightness is your main priority, it's around 100g less than anything else here.
The lightest thing out there and still decently warm.
More at www.mountainhardwear.eu.
Rab Infinity Jacket - £230 / 439g
Another mix of Pertex Quantum GL ultra-lightweight, semi-translucent fabric together with 850+ fill power down that Rab says is its best ever fill. It's heavier again compared to the Ilam or the Ghost Whisperer, but the pay-off is that you get a far bit more warmth thanks to additional down which together with hood and hand-warmer pockets makes it a good all-rounder for those who want a bit more warmth in their jacket. It has a nice microfleece chin-guard too.
It's great for hut-to-hut trekking when you have to carry your own kit rather than letting the yak take the strain or for general lightweight use.
Arguably the best balance of wamth and weight here. It gives you appreciably more insulation than either the Ghost Whisperer or the Ilam, while still weighing just a little over 400g for a medium. See our full review for more details.
More at www.rab.uk.com.
Rab Microlight Alpine Jacket - £160 / 365g
Not in the same insulation bracket as the jackets we've looked at so far, Rab's Microlight series of micro-baffled down uses slightly lower loft filling and a heavier fabric for a slightly more robust bit of kit. The idea is that it's useable not just in winter, but in cooler spring and autumn conditions as well.
We've found it works well in drier climates, but in the more changeable UK conditions, we'd consider opting for a lightweight synthetic alternative instead. That said, at 365g it's as light as a mid-weight fleece, more packable - it stuffs into its own pocket - and a fair bit warmer, plus its windproof too making it a good cool weather hut or tent garment, but less of all-out winter piece. Our original 'acid' colour still looks great though.
More of a three-season down jacket, if there is such a thing, rather than an out and out winter top, but handy in the right situation.
More at www.rab.uk.com.
The North Face Super Diez - £280 / 425g
The Super Diez is a development of last year's Diez Jacket and uses the same mix of Quantum GL, 900+ fill power goose down and stitch-through baffles. On paper it's very similar in spec to Rab's Infinity Jacket and weighs a mere 14g less and like the Infinity it's a step up in warmth from the MHW and Berghaus jackets, however it lacks the Rab's hood, which, to our mind, reduces the versatility of the jacket when things get really cold. It's also more expensive. On plus side it looks great and has some neat touches like hem cord adjusters in the hand-warmer pockets.
Similar performance to the Rab Infinity, but at a higher price and without a hood.
More at www.thenorthface.com.
Generally the lighter a down jacket is, the smaller it'll pack thanks to lighter fabrics and more compressible down, but to give you a visual guide, here are six of the jackets in the test stuffed into pockets - or in the case of the Rab Infinity and the Berghauus Ilam, the stuff sac supplied. Both the latter would squeeze down smaller however, the Rab stuffbag is larger than it needs to be and the Berghaus one is stretchy.
Anticlockwise from top right the jackets are: MHW Ghost Whisperer (orange), Rab Ininity (grey), Rab Microlight Alpine (grey/acid), Columbia (black), Berghaus (blue), The North Face (dark green)