Monday, 13 June 2011

snug as a bug: the western mountaineering ultralite sleeping bag

in a very expensive sleeping bag.

Normally, I’d resent the idea of having to pay for a product that someone is wanting me to go out of my way test and then spend hours writing a review of. In some cases however, chipping in toward being given something truly special really is worth it, even if you are as tight as I am (Scottish blood? Sorry Dad…)
Back before January’s life changing house fire, I had a choice of two sleeping bags that I could use – one a lovely Marmot Pinnacle, given to me by the man who designed it (it’s a long story that I’ll only tell if you manage to catch me in the pub and buy me a pint), and the other an Alpkit Pipedream 400 I’d bought to use on Alpine climbs because it was light and packed down tiny. I’ve also used all manner of cheapo Sleeping bags over the years, but absolutely nothing I’ve ever used has come close to comparing to the new love of my life – the Western Mountaineering Ultralite.
The quality of this bag really does merit a better testing than I can really give it at this time of year – it yearns to be taken out in the cold of the autumn and winter. Camping in the snow, all snuggled up inside, surrounded by a gorgeous cocoon of stupendously lofty down? Definitely what the Ultralite is begging me for. Unfortunately in that regard, we are currently in what counts as the British summer, but of course, being in Wales means that actually, the ‘summer’ weather can be pretty atrocious and at night it can still get pretty cold. The bag has now had what I consider to be a semi-reasonable testing in areas as varied as my attempt at riding the Trans-Cambrian way (where it sat taking up very little room in the bottom of my riding rucksack), to just sleeping outside the house in a bivi bag as I was watching the owl babies learning to fly, to tent camping on a very cold night near the summit of Cadair Berwyn, amongst others. I’d still like to come back to this review once the bag has seen some winter or Alpine action, but for now here is my review.
Spec list
Currently (12/06/2011) £323.99 from Webtogs unless you’re a short-arse like me, in which case they will let you have one of the Short length ones for £314.99.
  • 454g of 850+ fill high loft down (425g in the Short one)
  • 3D down baffle behind zip
  • Full down collar
  • 5 inch loft from finest goose down filling
Tech Details
  • Short length weight: 790g
  • Standard length weight: 820g
  • Long length weight: 870g
Temperature Rating
  • 20°F / -7°C Now, this is the controversial one, and I’ve simply quoted what W.M. have quoted on their website. I will comment later on about just how warm I think this thing really is and where/when I’d be most happy to use it (my own ‘real world’ opinion, as temperature ratings of sleeping bags really are pretty unhelpful in all honesty).

For a little background information, I actually spent last Friday up with the guys at Beyond Hope – the UK importer for Western Mountaineering (amongst other brands), admittedly on unrelated business, but, I did have the opportunity to have a proper discussion about W.M. bags, their construction techniques, the quality of the down they use, the testing they do, and why people rave about them. I’m not going to go into everything on here, but one thing I will mention is that the quoted 850+ fill-power down used in all of the W.M. bags, may actually be more like what we usually know as 900 fill-power – of the same quality as the very best stuff that manufacturers like PHD use (for anyone unfamiliar with the name PHD, go look them up – they are the home of UK made custom sleeping bags, jackets and other insulating products of the highest quality and practically much an institution in Climbing and Ultralight circles. My comparing W.M. with PHD is nothing but a massive compliment to both companies).

Field testing, always a hardship. Keep your eyes open for the review of the Nemo mat I’m lying on here later on too…
W.M. have produced a fantastic page on their website outlining the features of their sleeping bags that really deserve to be noticed, which makes my life easy as I can just direct you to the link and then simply comment on the elements that I really liked and feel I should draw attention to.
“You look like a worm! A giant, blue, poofy, snuggly worm!” I think I’ll take that as a compliment…
The important stuff and my opinions
  • Loft. The first thing you notice about the Ultralite, the moment you pull it out of it’s fluorescent green cotton storage bag (yes, I did say fluorescent green), is just how much it lofts, instantly. In all honesty I’ve never seen a bag quite like this, even after it had been crammed into a stuff bag for a couple of days, upon pulling it out in a matter of mere seconds it will have re-lofted back to being possibly the snuggliest thing I’ve ever seen.
  • Weight. It’s light. Really light. And it packs small. This bag is made from some of the highest quality down money can buy, and some of the lightest, most down-proof fabrics you can find. The warmth-to-weight ratio of this thing is simply phenomenal. If anyone can find me a bag to beat this in terms of warmth-to-weight, please let me know as I’d absolutely love to see it. This will be my go-to bag for pretty much everything now, all year round. Admittedly, in the depths of winter I’ll probably need to be layered up inside it (being a girl who suffers the cold), but for 95% of what most people would consider ‘three season’ use I’d be more than happy in this (and I’ll use it in all four seasons).
  • Fabric. W.M. also use a fabric that is impressively down-proof. Normally with a down bag, you open it up and inside you’ll inevitably see a few bits of rogue down floating around having leached through the fabric or the seams. There are far less escapees in this bag than with any other I’ve seen (Marmot, Alpkit, Rab, Mountain Equipment…). 
    The fabric feels absolutely gorgeous next to the skin, it is positively luxurious.
  • Zip. It’s the little things that can often make or break a product, and in this case the way W.M. have presented the zip issue is nothing short of ‘shout out loud’ refreshing. Not only do you get a zip with a tag on each side (rather than one that you have to slide round to get it inside and never seems to start on the side that you want it), but they’ve laminated a strip of the fabric each side of the zip, stiffening it, thereby preventing the fabric from being pulled into the zip. Stick and snag free zippage! The bag is almost worth the price-tag for this simple feature alone in my opinion.
  • Construction. There is some clever stuff going on here with what Western Mountaineering call a ‘Differential Cut’ in the main body of the bag:
    “Its purpose is to give the inner shell a smaller circumference than the outer shell. This eliminates extra fabric inside the bag that could lead to cold spots. All of our mummy bags are differentially cut to promote proper lofting and to protect against down compression when knees or elbows push against the inner fabric.”
    They also build in what they then call a ‘Reverse Differential Cut’ in the hood of the bag:
    “Our hoods are cut so that the inside of the hood is made with a larger piece of fabric than the outside. This creates a hood with loose down filled fabric which surrounds your head. That way you can can enjoy warm insulation around your head and face without having to cinch the hood tight. Also, the extra fabric can be adjusted to create a down filled ruff or bill across your forehead.”
    Both of these work – cold spots are much reduced around joints when you stretch and move, compared with a more conventional bag construction, and the hood is indeed wonderfully snuggly without necessarily having to do up the drawcord (which is something I absolutely hate having to do – having a small circle to breath through and a cord pressing into my face really doesn’t feel great).
In short, I think this sleeping bag is one of the best and nicest pieces of outdoor kit I own. It’s not something I would ever have considered buying had I not been offered the testing gig as it’s a cut above my normal sort of price operating range, even for high level equipment. However, now that I’ve experienced what the top end actually buys you, I’m not sure I’d ever feel happy buying a ‘lesser’ bag now. The quality of design and construction is impeccable, I have found absolutely nothing whatsoever to criticize in this sleeping bag (and you all know by now that I’m particularly anal about things that annoy me or are what I consider to be sub-standard).
It’s light, incredibly warm, supremely comfortable, fits me like a dream (I could wear layers inside if I wanted to) and actually makes me want to find excuses to use it. The simple genius of the reinforced zip strips mean the zip hasn’t even bugged me by getting stuck as they inevitably do normally. The draft tube that covers the zip is squishy and lovely (so basically it’s full of down and actually really works), as is the neck baffle. The foot has extra down in it so I’ve managed to even get away with not needing my socks on inside it (a first!). The drawcords work, the storage and stuff bags are adequate (although I choose to transport the Ultralite inside a lightweight roll-top dry bag to protect it), and it isn’t even a bad colour!
The only down-side is the >£300 price tag, but in all honesty, with the amount of care, attention to detail and the level of component and construction quality there is just no way I can argue that the cost should be less – this bag is worth every penny. It’s available in three different lengths and anyone of a slightly broader build than me could also look at the Western Mountaineering Alpinelite, which is essentially the same bag as the Ultralite, just with a wider cut!

The link bit
Other down sleeping bags, including others from Western Mountaineering:
Western Mountaineering’s homepage:


  1. differential cut is nothing new. the loft figures are US and not EU - still top end tho. its sewn boxwall construction which doesn't make it effecient - shud be trapezoidal. 16oz of down is about right for 3season damp english use not winter. no way. not enough down at all. whats traditionnal sleep bag construction? theres loads of different ones

    what fabric is the shell? is it water repellant

    why store a bag like this in its stuffsack for 2days? you'd store it loose to keep its loft in the long term if not in use or youl ruin it

    £300? rip off! you can get down bags of better construction with more down for less money and weigh less

    does look nice tho. but for the money your review misses some key issues. not dissing. is it good on the hike for 7day or loss of loft from damp? you say your anal, so am i and you dont know what ya talking about with hi end gear it seems.

    you just liked it and filled in the blanks by googling info or talking to the company methinkgs sorry but nice words and pics but i want to know more for $300

    think ill stick with me phd one. costs less with more down sorry

  2. Thanks for the read and the comments - it's great hearing other perspectives on kit and reviews! I would just like to reply to a couple of things you've said though:

    Firstly, the fill rating - the down used in these bags goes through more fill power tests than you can shake a stick at. 850+ is an incredibly conservative rating given by WM and I've been told that the down actually gets tested by the producer in Poland at a rating of around 900fill EU. What WM quote is slightly mysterious I will admit.

    Secondly - not enough down for winter use? Really? I'll happily use this bag in the winter as personally I don't mind suffering a little bit, nor do I mind sleeping with a down jacket on inside a bag if things get really bad - after all, I'll more than likely be carrying one so why not wear it? I have used far lesser bags down to around -25C before now, so whether or not you could use this bag in winter really is just a matter of personal preference - for many people (such as yourself) this bag wouldn't be warm enough, you're right, which is why in my review I simply said that *I* would be happy to take it out in winter. It's not rated as a four season winter bag, WM make rather heavier offerings for that.

    Thirdly - in the stuff-sack for 2 days? Yep, my bad, of course it should be stored in the big bag, but sometimes life gets in the way and plans change, hence sleeping bags occasionally get left inside stuff bags for longer than is ideal - good idea to test the effect this has though don't you think? I certainly did...a bag of this quality shouldn't suffer too much from the occasional bit of abuse after all.

    Fourthly - in the review I did ask if anyone could point me to a better/lighter bag, so please give me links to the bags you speak of, seriously I'd love to see them! (Are you thinking of PHD?) The WM is by far and away the best bag I have used, but of course that's not to say it is the best bag around! Nor have I used every high-end bag of this type!

    Fifthly - you ask how well the bag would cope on a 7 day hike. A fair question, and one which I haven't answered simply because it's not the style of things I do - I'm not a long distance walker, I'm a climber and an alpinst primarily, so my reviews will always be geared around 'quick hit' style useage.

    Lastly - you say I don't know what I'm talking about with high end gear? Hey, maybe you're right, but I'd like to think that actually I know enough to be able to use, test and pass a fair judgment on the equipment I choose to use, whether it be something I'm given to test or something I've chosen to buy for myself. Gear reviewing isn't an exact science, and I don't know every little detail about every product I test, and I don't claim to, I just give my opinions based on the little knowledge and significantly larger volume of experience I do have.

    Hope this answers some of your questions, and thanks for the feedback!


  3. fill power dont go higher than they say realistically. so dont believe all they say lauren

    often the weight of winter bag is less than tkaing extra clothing and arguably cheaper. 16oz of down is not enough for winter hiking no way. down loses some loft over 3days or more due to damp and more on a long hike. theres loadsa reasons

    so £300 is a rip off really

    no offense was meant with post. just it spoke volumes and £300 on this down bag is some sum and id want a more in depth and know how review

    a sleeping abg more suited to your activity would be better and not something like this that costs as much as it does

    i could do a review on expedition kit but it aint the same as someone who goes on expeditions and knows what really happens to gear. therefore their review would mean more and be related to the product

    why review a product you know little about? be better to review a product more suited to what you do if you know what im saying

    yes im anal. sorry but just my thinking. you did do a nice review and on that front id give it ten out ten. well done. nice you talked back too. but be best to stick with suitable gear to your activity methinks. bye

  4. Firstly, it was a very good, detailed and thoughtful review. So thanks.

    I have a WM Summerlite and I have found it to be an excellent, superbly manufactured bag. WM have a reputation for finely constructed bags using high quality down and that certainly comes through in my experience of their bags in comparison to Mountain Hardwear and Rab (where my experience of other bags lies). Rab are also excellent, but not as light - and that's the trick - getting a bag that keeps you warm, packs down small and weighs very little. Yes PHD bags are legendary but also very expensive too - the equivalent PHD bag is the Hispar 400 (albeit -9C rather than -7C) but that's £378 so I don't see where the argument is about the cost, but there you go. In my view, you get what you pay for and a bag that light, and that warm, is worth the money when compared to the rest of the market.

    However, my Summerlite failed badly when condensation from my (erstwhile) Hilleberg Akto overcame the "water repellent" outer. So there are caveats to every purchase - PHD Drishell would have fared better (my PHD Yukon was the only thing keeping me warm and its outer kept the moisture out) so I surmise that a PHD bag with a Drishell outer would perform better than the Ultralite under similar conditions.

    As I said - good review, useful and enjoyable reading.

  5. Maz,
    Thanks for the comment and the time you took to read my ramblings! You raise some interesting points regarding the water repellancy (sp?) of the fabric used in the Summerlite and the Ultralite. I had heard similar stories in fact, but I guess you're paying the weight vs. features price yet again.

    PHD Drishell in many cases could well be a better outer fabric, or if you're sticking with Western Mountaineering, a bag like the Apache which is made with Gore Windstopper fabric. Of course, bags of this ilk are going to be slightly heavier and slightly more expensive for the same spec. Horses for courses as you say!

    Just out of interest, where were you when you had your condensation issue and what kind of temperature were you using it in? These are all bits of info that add to the review (and it's great getting views from people other than just myself!!)


  6. Lauren,

    I was on Yewbarrow in January this year, it was hovering just above 0C and although I was not camping on snow, I was just below the snowline. It was wet and windy and I was in an Akto. Were it not for the condensation, the Summerlite would have done a great job - I was in a PHD Yukon and also using a Sea 2 Summit Reactor liner to supplement the Summerlite if it went appreciably below 0C.

  7. Yewbarrow - Lakes? Lovely. That kind of weather is pretty much the worst kind for any sleeping bag/tent combo I think - condensation plus cold. I think the outer material of these bags is probably the weakest point (if you can even call it that!), but as we said earlier it's a trade-off - you can either have the super weight savings OR have a bag with a more water repellent outer OR even a synthetic fill, which is of course another discussion altogether.

    I'm looking forward to getting out with the Ultralite once the temperature starts to drop - give it a proper testing in the cold!

  8. I think it will do rather well - I recommend the Peak Oyl Mtn mat for winter - did a post on after the Yewbarrow trip - great mat.

  9. I've not heard of that mat - time for some research! Currently testing a new Nemo Zor, which is a super light but also very thin (1in) self-inflater, certainly not something I'd use in the winter!

  10. Great review Lauren. I've also been super impressed by the Western Mountaineering down, and would agree it's definitely closer to 900 rather than 850. Normally down is measured by getting it fluffed up and left to settle for a while. The WM crew apparently shove it straight in and measure there and then. I've never seen items that loft so quickly straight out of whatever you have stuffed them in to!

    In terms of the waterproofness, I would agree if you think thats a concern to go for one of their GWS bags, but I have never had any isses with my summerlite.

  11. Hey there, stumbled onto your blog and I loved your review of the WM bag! I went overboard with mine as I'm a cold sleeper by buying the WM Lynx Gore. My word that bag creates a furnace! Fantastic! Oh yeah, Mr Anonymous comments are a complete bore. Firstly anonymous for starters and if he's so clever why doesn't he write a review somewhere? You were very diplomatic with him as I wouldn't be quite so nice to someone so arrogant and dismissive :) I love your blog. Keep it up!

  12. Hey Greg, thanks for the kind words!

    You went for the Lynx? Nice! I can well imagine that must be warmer than a warm thing on a warm day :-) Where are you using it?

  13. Oh yeah, the Lynx is mega overkill, but after spending some really cold nights in the Tasmanian winter last year I decided I wanted to cook at night rather than freeze! It's not the only bag I have, but I'm using it this winter at places that are 1000 metres plus. Hey, that's high for down here! It has a bit of weight to it, but I'm not a real ultralite bloke. I figure it would be better to lose 10 kgs off my body first before losing a kilo or two out of the backpack :)

    Oh yeah, with the Australian dollar riding so high I found buying the WM bag from America to be a no-brainer. Normally it would be out of my price reach, but I got a great deal as something comparable over here would cost hundreds of dollars more. Thanks for the reply :)

  14. There's something wonderful about crawling into a really lovely warm sleeping bag after a long day, especially a long, cold day. Definitely worth a bit of extra weight in my view - I only go minimal when I'm climbing as it's then that the pack is heavy. When you're used to carrying a load of ropes and metalwork, a few hundred grams on a sleeping bag is nothing!

    Been having a read of your blog - looks like good fun out there!

  15. Yeah, the weight is relative in the end as there's nothing worse than a cold sleep whilst hiking!

    Thanks for dropping by my blog. I've embraced the 'totally nuts' style of hiking blog :)