Down Or Synthetic Jacket?

After some luxurious winter warmth? We outline the pros and cons of different fillings.

Posted: 22 December 2009
by Jon

Down or synthetic jacket? That's a question a lot of OMers are asking themselves and each other as temperatures fall, so what are the pros and cons of each and which works better for UK conditions.

Down Jackets

Down has pretty much the best warmth to weight ratio of any clothing insulation. It packs down into a small space, traps a lot of air relative to its mass and is also surprisingly durable if cared for properly.

All of which is great. Down does have an Achilles heel though, it doesn't like damp - when down gets wet, the surface tension of the water overcomes the ability of the tiny down fronds to expands - think wet hair in the rain - and the down loses pretty much all insulation value and collapses into a soggy mess.

Mountain Equipment Vega jacket

Many down jackets have water-resistant or even waterproof outer shells, but these are designed more to cope with wet snow and the odd very light shower than proper rain which will, inevitably, get to the down in time. That's the case even with fully waterproof outers, eventually rain will get in through the neck for example, though they will cope with some wet weather use particularly if you keep the hood up. Ask yourself though, will you really need the warmth of down if it's warm enough to rain rather than snow?

Because of this, down works best in cold, dry conditions and inside when the temperature plummets. It needs more care than synthetics, a waterproof stuff sac is a good move, is more expensive and harder to wash.


Primaloft is the best known 'down-like' synthetic filling but other synthetics have broadly similar qualities. Synthetic fibres aren't as light or compressible as down and have an inferior warmth to weight ratio, but they do have two big pluses:

Mountain Equipment Fitzroy jacket

First they are often hydrophobic and retain far more of their insulating capacity when damp, so you can layer them over wet clothing without worry and not panic if it starts to rain. Second, they're easier to care for - you can simply chuck them in a washing machine, unlike down which needs special care.

For a lot of UK use, that makes synthetics more user friendly and more versatile, though they do lack some of the fluffy weightless warmth luxury that makes down so attractive.


As you've probably surmised, for a lot of UK active use, synthetic insulation is a lot more user friendly than down. On cold, dry days, down has unrivalled warmth to weight properties, but add UK-style rain and humidity to the equation and synthetics, with their wet-friendly properties and knockabout care qualities make more sense.

Logically then, you'd expect synthetics to outsell down in the UK. In reality that's not always the case, Rab, for example, sells far more down than synthetic jackets, probably because a lot of down-type jackets are used most for apres-mountain activities like walking to the pub or sitting around a bunk house when water resistance is a lot less important.

The Bottom Line

The bottom line? In our opinion, for versatile active use, go for a synthetically-filled insulated or belay- type jacket which you can layer over other kit even in damp conditions. For cold dry alpine or trekking use or for simply going down the pub at the end of the day or sitting around in huts, tents and bunk-houses, then down is lighter and warmer for its weight.

Be realistic about your needs and make you choice on that basis and you won't go far wrong.

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Discuss this story

You can't go wrong with down!

YES, if you get it wet then its practicaly useless but you should never be using a down jacket when its raining anyway, it does need a bit of extra care when washing and storing but you pay alot of money for your kit so you should atleast look after it. I use a rab glacier down jacket for the winter when I might be bivving or camping out especially when high up in the mountains. Theres nothing better than putting up the tent or getting out your bivvy bag while you wear your down jacket, this is afterall when most of your heat is lost after activity like walking up the hill, also does nicely when your reluctant to get out your down bag in the morning!!!

I have had my down jacket and down bag for almost ten years and both are still in great condition, a truely great investment.

 By the way, my picture is me wearing my down jacket just below the summit of Ben Dorain on a very cold january morning after bivvy out, toasty!

Posted: 24/12/2009 at 09:11

Never really seen the point of down if you're in the UK and are into year round hiking 'n' stuff - the cons re: performance when it gets wet far outway the warmth to weight ratio benefits in my humble opinion.

Synthy stuff is getting better all the time as well I think

Oh and the ability to just throw a synthetic belay jacket on when its really grim, cold and wet is just wondeful!

Posted: 24/12/2009 at 20:00

Have to agee with Phil here. I have a ME Lightline for climbing and on dry days at a crag its brilliant to throw on after a pitch. but the versatility of modern synthetic jackets means when in the UK I wouldnt go anywhere without it. Purely due to not being able to garantee the weather. Especially now they are starting to be available in different thicknesses to rival down fill power. Jackets like the Paramo torres and the Berghaus infinity light.

I know that even if i am caught in some nasty rain unexpected my primaloft will keep an element of warmth whilst i either get undercover or overlayer with a waterproof. The same cant be said for my Lightline unfortunately.

Posted: 30/12/2009 at 14:37

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