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  • Ultralight Shopping-- Winter Sleeping Bags

    Written by Guthook at Guthook Hikes!

    This is a slightly modified version of a post from my blog about my thought process in searching for new sleeping bags. In this case, I looked at winter bags, but this would work well for any season bags. Last year I managed to get a Western Mountaineering Lynx GWS for a winter sleeping bag, but it turned out to be too much– as in, too warm, too heavy, and too bulky for what I needed. The Lynx is rated to -10 F, but I was able to easily take it down to -30 by wearing down pants and jacket to augment the temperature rating. With that in mind, it didn't seem useful to carry the extra weight and bulk of a too-warm sleeping bag when I could carry a lighter one. So it's time to do some research!

    Airing out my WM Lynx last winter after a chilly night in the White Mountains

    Which Sleeping Bags to Compare:
    I started with the sleeping bag I already have, the Lynx GWS, and looked for other sleeping bags that have a similar size, weight, temperature rating, and quality. The list I came up with, unless otherwise noted, includes standard-sized, zero degree, 800-850 fill power down sleeping bags. The selection of bags I've chosen is mostly based on the bags I had available at my local stores, so this is by no means a comprehensive list.

    Western Mountaineering Lynx GWS
    -Weight (Total / Fill): 56 oz / 32 oz
    -Notes: My current bag, rated to -10 but much warmer in my experience.

    Western Mountaineering Antelope MF
    -Weight (Total / Fill): 39 oz / 26 oz
    -Notes: Rated for +5 degrees, but anecdotal evidence suggests it can go much lower.

    Western Mountaineering Kodiak MF
    -Weight (Total / Fill): 44 oz / 30 oz
    -Notes: Sized wide for big folks, but the extra width may help with layering extra clothes inside the bag.

    Marmot Lithium
    -Weight (Total / Fill): 44 oz / 28 oz
    -Notes: Nothing out of the ordinary here, just a good all around bag from what I hear.

    Marmot Couloir
    -Weight (Total / Fill): 55 oz / 31 oz
    -Notes: EN rating for Couloir is slightly warmer than Lithium, though Marmot claims both are 0 degree bags.

    Eastern Mountain Sports Mountain Light 0
    -Weight (Total / Fill): 44 oz / 26.4 oz
    -Notes: The most inexpensive of the bunch by far.

    Golite Adrenaline 4-Season
    -Weight (Total / Fill): 50 oz / 31 oz
    -Uses a chest-zipper instead of side-zip, which actually seems kind of nice to me.

    How I Compare the Bags:
    As you can see, I'm comparing two basic specs for these bags: total weight and fill weight. Why those, you may ask? Temperature ratings vary greatly across different manufacturers, so assuming all these bags will be comparably warm is generally wrong. EN Ratings are a standardized rating, but not many major manufacturers list these ratings, so that's no help for now. What I can use is the weight of the down in each bag as a reasonably accurate assessment of how much insulation value each bag has.

    I gathered data for girth measurements of the sleeping bags at first, but found that those measurements couldn't really be trusted between manufacturers. Some measured the inside girth, others the outside girth. But it didn't matter so much, because I found that most of the bags, aside from the Kodiak, were within an inch or two as far as sizes, so I disregarded the measurements.

    What about variable circumference laser-welded ergonomic Thermo-Amazingness (tm) and other features?
    Let's face it– a sleeping bag is not much more than an insulated tube. The heat comes from your body, and the bag's job is to hold that heat in. Fancy baffles, ergonomic hoods, no-snag zippers, and those other bells and whistles may be handy, but they won't generate the heat for you. When it comes right down to it, the only innovations that make a huge difference are lighter shell fabrics, and simplified construction. Everything else is just frosting on the cake. In this case, the cake is the most important bit. (This isn't to say the other features aren't nice, but for me they're not a high priority in the decision-making process).

    Since the fill power and size of most of these bags are similar, I'm assuming that by looking at the amount of the fill I can get some idea of how dense the insulation in each bag is. This isn't an exact science, but if you look at the two Marmot bags here, the Couloir has a slightly larger girth, with almost 11% more down fill. No wonder the EN rating shows the Couloir to be warmer. However, for that bit of extra warmth in the form of 3 ounces of down and some more shell fabric, we get 11 ounces more of total weight. Is it worth the trade? Maybe, maybe not.

    Weeding Out Bags for Testing
    -The Couloir looks all too similar to the Lynx (one ounce less in both full weight and fill weight), which I've already decided is overkill for my needs, so the Couloir is out.
    -The Adrenaline is six ounces heavier than the Kodiak for only one ounce more of down insulation. I can make up that extra insulation with jackets and pants inside the Kodiak, so the Adrenaline is out.
    -The Lithium and the Kodiak have the same total weights, but the Kodiak has two more ounces of down. This is a tough call, since it means the shell fabric of the Lithium is heavier, but the Kodiak's extra girth would be inefficient. I'll cut the Kodiak out for now for this reason, but I may revisit it later.

    So that leaves three out of the initial six bags to compare: the EMS Mountain Light 0, the Western Mountaineering Antelope, and the Marmot Lithium. All three are snug-fitting with similar fill. The Antelope and Lithium are well-tested and get great reviews. The Mountain Light is new and intriguing. The Antelope and Lithium are relatively simple in construction, while the Mountain Light has high-falutin' vertical baffles. Marmot and EMS use this "new technology" in some of their new sleeping bags, but that sounds to me like adding more blades to a razor and calling it a "stunning new breakthrough!"

    This is as far as I can really take the theoretical testing for sleeping bags at this point. My plan from here is to see if I can rent a Mountain Light bag from EMS for a trip or two to decide if it's good enough. If so, I'd gladly take it since it's inexpensive, light, and should last a lifetime. If it's not warm enough, I can probably assume the Lithium is the way to go– a little more down, similar weight, and anecdotal evidence suggests it's good to well below zero.

    As for prices weighing in on the decision, I haven't discussed them here only because most of the prices are quite similar. They are definitely weighing in on my decisions, though. I'm just choosing to do that part of the decision making process behind the scenes for now.

    Non-Winter Sleeping Bags:
    You see how my research goes for winter sleeping bags now, but how about three-season sleeping bags? This is a more involved question for me, because I now use a quilt instead of a sleeping bag, but if I were looking for a three-season down mummy bag, my decision making would go pretty much the same way:
    –Choose high-quality manufacturers who use high-quality fabrics and insulation.
    –Compare the amount of insulation and the total weight of the fill, not just each manufacturer's claims about temperature rating and weight. But compare similar fills-- 650 and 600 fill weight aren't so different, but the difference between 600 and 900 fill is big.
    –Don't worry about gimmicks or bells and whistles. Remember: it's an insulated tube. The only extra feature that I'd pay a lot of attention to is whether the baffles are continuous or blocked, which tells you if the down can shift around to better insulate one area or another.
    –Take your time in choosing a new bag. If you choose right, it can last you a lifetime. My The North Face Beeline has over 5000 miles of use, including the entire Appalachian Trail and Pacific Crest Trail (so approximately 250 nights of use), and it is still running strong.
    Comments 2 Comments
    1. RJ Lewis's Avatar
      RJ Lewis -
      I have the Couloir, and spent 3 weeks in it up in the New Mexico highlands, with night time temps often running into the single digits and teens with high winds, and a tarptent. It was plenty warm for me with just a tshirt and underwear on, and in fact had to unzip it in the middle of the night because I became too warm. I ended up using it as a quilt, just thrown over me.
      I think the other thing that needs to be considered when you buy a bag, is the pad underneath. A good winter pad, like the Exped Downmat7, can extend the warmth of your bag by quite a bit, whereas a microthin pad could do just the opposite.
      I own 3 Marmot bags, and absolutely love them all. WM has terrific bags too, especially the size ranges for bigger hikers.
      My 3 season go to bag is Marmot's 15F Helium. I've used it down to 0F with a winter pad, and its weight is decent at about 2 lb.
    1. sparky2000's Avatar
      sparky2000 -
      Excellent ! This helps me analyze. Price is still the controller.