I hear ya Roger. There's nothing like learning to make your own. Save money (in the long run) and end up with EXACTLY what YOU want based on YOUR needs. But for many folks, the time, energy and practice it takes to get to this stage is just not their cuppa tea. And the original question is a little bit different as it's comparing two sleep systems from the same manufacturer, same fill and shell, same weight, same baffle height, and same 'size". According to Nunatak's website, their Arc Bag is 61 unches "girth", same overall weight (fill and total +/- 15 grams)and same overall temp rating as their 55 inch girth Arc Quilt of the same length. I think this, more than anything else, is the conundrum. With those kinds of specs, why wouldn't you choose the bag over the quilt, since you can always use the bag up-side-down as a quilt (admittedly with a hood in your face), but you can't zip up the quilt and have a bag + hood with the quilt?

My experience to date (with MYOG stuff), is in the difference between baffle 'height' and baffle 'fill'. A Baffle is just a strip of fabric that separates down chambers and allows greater 'loft'. No where on Nunatak's website does it mention 'loft' for either of the systems, which leads me to believe the Arc Bag must have a lower loft OR a lower down density than the Arc Quilt. How this relates to temp rating is anyone's guess. We're never gonna answer this question by speculating, or pushing theoretical numbers around.

John, two down bags of equal fill weight, with equal fabric and equal total weight will almost certainly take up the same space when compressed. You are the only one who can decide the whether the benefits of perceived comfort or warmth are more important to you. Whichever you choose, please keep in mind that insulating your head is almost unarguably the most important aspect in keeping warm, so if you go with a quilt, you need to match your headwear to the quilt. And also consider that, if you want to get your pack volume down, then down will be superior to all other insulation unless you sleep in a puddle or 110% humidity for weeks at a time. Perhaps you could consider upgrading at least some of your insulating clothing/beanie to down...

Must have cross-posted with Beenay's post above. All I can say is thatpretty much sums up my opinions. Since most of the down quilt makers we're talking about will do custom work, it all just comes down to

1) Working out what is right for you;
2) Communicating this to a custom quilt/bag manufacturer, and;
3) Paying for it.

Number one is by far the hardest, and is different for every body.


2)

Edited by retropump on 01/20/2008 22:25:01 MST.

>>And the original question is a little bit different as
>>it's comparing two sleep systems from the same
>>manufacturer, same fill and shell, same weight, same
>>baffle height, and same 'size".

Good point, I was mainly going for an answer to the "When a bag is better than a quilt," general idea. It seemed that it had already been established that these two products from Nunatak had the same temp rating and the same weight, but different designs, but when I read the most recent posts, I see that there is still some uncertainty on that...

I totally disagree with the comment that mummy bags have wasted down on the back. This would only be true if you never changed position and I think that is very unlikely. Mummy bags are warm because they eliminate drafts and that wasted down is what allows us to eliminate the drafts. If you have any experience using mummy bags in cold weather you will very quickly figure out how to turn over without losing the hood and keeping the bag in a perfect orientation as not to create a draft. I've never noticed a cold spot where the down was compressed and can only assume that it regains it's loft very quickly.

When you flop around under a quilt you create drafts. This is exactly the reason I open up my down bag in warmer weather and use it as a quilt... the drafts keep me cool every time I move. It seems to me that the warmest quilts are really being designed to hug the body like a mummy bag... to try and prevent cooling caused by drafts.

Again, this comes down to sleeping styles... if you never move, you won't create drafts, so a quilt will have the best warmth/weight ratio. That said, most of us move while we sleep.

Unless your body suspends itself in mid-air, there will always be a certain quantity of down and shell/liner material flattened by your body. True, when you turn over, that flattened down will regain its loft. But then another quantity of down and shell/liner will be flattened.

That's gravity for you.

In any event, everyone has their preference for whether a quilt or bag works best. I suspect that many quilt users used bags before turning to quilts, and are not without a basis for comparison of what works best -- for them.

Not trying to convince anyone that their choice isn't best for them, just clarifying that there is loss of loft from down while it is flattened by the weight of a body. Only way to avoid that fact is to levitate.

JRS

Allison - With respect to the Nunatuk Arc Alpinist loft, mine measures at 3.25 inches,YMMV. I have 2oz overfill, but this is offset by the heavier Epic fabric. For me the big quilt advantage is comfort, but I consider it slightly lighter for the same level of warmth. At 27oz I've used it to around 20 degrees.
Ron

GL, et al,

I raise a caution to GL's comment that "quilts can be pulled closer to eliminate dead air space"....

While this is true, it is also true that quilt users and bag users for that part also, can pull the quilt/bag too tight and actually reduce loft... Thus one will actually be colder....Sleep systems need to be loose enough to loft fully to achieve maximum performance....

As an aside.... Consider the ground sleeper when changing positions thrusting out an elbow or knee, or tristing the foot box as one rolls the bag with one (vs rolling in the bag).... These points create thin spots and cause cool spots, Thus waking the sleeper due to the cold and/or causing more frequent position changes in an attempt to get warmer.....Ironically, we have all heard the term "hunker down".... Too much so is often an inefficiency...

Pan

hey all,
good discussion, some comments on the various last messages:

I don't know what the shoulder girth means for an item with variable girth like a Nunatak Arc (I haven't measured mine and I don't know how it compares to the girth in any other bag). What I mean is I don't know if it's fair to compare girth numbers across manufacturers to conclude standard Arc quilts are narrower. If someone finds them narrow after trying them that's a different thing. The stated 55" shoulder girth is perfectly ok with me, I have room to move and to wear high loft clothing inside but I'm on the slim side.

A bivy (or bag cover, as they're usually called when not meant as a stand-alone shelter) may be useful even if its shell is the same as the bag's it's covering. I said it before, no matter how water resistant the bag shell is, if there's humidity on top of it that didn't penetrate, it will when you store the bag. You can do a good job of wiping it off before storing but something will remain and it'll go straight into the insulation. You can avoid this happening at all with a bag cover. This applies to rain splash, dew or condensation falling on you from your walls above so it's not only about using small tarps in rainy weather.

I don't agree drafts are granted with a quilt. They may be for some but not everybody. I never felt they were a problem for me. I move when I sleep when I turn sides but I do it with reasonable care. It's happened to me that I became too obsessed about moving carefully to avoid drafts which is not good for sleeping comfortably. Maybe too much reading about drafts :)
but seriously, and particularly thinking of potential readers who haven't tried a quilt, I think the draft issue is a bit hyped. As ususal, it must not be the same for everybody.

Another thing I'd like to point out is I find difficult to make comparisons between different models of either bags or quilts. Some people talk about numbers like this was simple maths and I think it's far more complicated than that. There are so *many* variables. I would only compare two different items after respective long term use (like a whole season) in similar conditions and even then...

I wonder if some of the apparent confusion resides around the terminology we're using.

Here are three different sleep systems, all set up in "bag configuration. The two on the left are true "bags" in that they have a hood and a zipper. The one on the right is technically a "quilt", so in fully cinched "bag" configuration, it relies in straps instead of a zipper. It's also BYO hood.



This is the middle "bag" and the "quilt" opened up in use as, what I would technically call a "top bag" configuration, as the footbox is still fully enclosed. The Arc Quilt in question is of this type, although the bag on the right is a true "quilt" in that it can be completely opened flat.




The red bag will have a zipper along each edge, and some extra material in the hood region, but otherwise acts exactly like the bag on the right. It also has a differential cut which helps it to hang better whether zipped or opened flat as a "top bag".

This is the true "quilt" in full quilt mode





The bag on the left in the first photo is a "bag", but only has down on the top, and half a zipper, so can NOT be used as a "top Bag" or "quilt" under any circumstances. Restless side sleepers do not like this kind of bag!

So which is best? Full Bag, Half Bag, Top Bag, Quilt? I mostly use the half bag these days as I am a solid back sleeper so I can take advantage of the great weight to warmth ratio offered by this system. Side sleepers and restless folks should avoid this type of bag like the plague, and will need to carry a less efficient quilt or top bag to get the same warmth (or bag that can be used as a quilt, like the red bag). There clearly is no BEST except what wors for you.

Edited by retropump on 01/21/2008 11:56:32 MST.

Nice thread. Thanks for the pictures Allison.

So which down bag do you all like best - to double as a quilt? Foot box, hood, and 3/4 length zip included.

I'm looking at the WM Ultralight, but would prefer the zip over the chest, opposite the hood. Will WM do this as a custom order? How does the Arc bag compare? Other recommendatons?

As a side to side sleeper I discovered I prefer quilt mode so I can change position without moving the quilt over me, (or moving off the pad); and without losing my airhole inside the zipped bag. I like the open hood over my head while I'm on my side. And in milder weather nothing beats the relaxed flexability and temperature control under a quilt. But when its cold I'm warmer zipped up.

In bags/quilts where you can shake the down toward the middle for more warmth, doesn't it tend to fall to the sides through the night?

The first question would be what's your max Girth?

Sadly, WM do not do custom work, but the Ultralite is indeed a great bag/quilt. But it is narrow as bags go, so yeah, your girth comes into play here. The Versalite (the red bag in the above photos) is 3 inches wider in girth, but heavier. I don't know what the Arc bag is like, but at least it has the chest zip and you can customize the size and fill to suit your needs.

They're all good choices (including the Arc top bag/quilt). One nice thing about WM is you can buy it and try it. Return/exchange it if it's not right. If you get a custom bag made, you're pretty much stuck with it...

I've tried on the Ultralight and it fits fine. Snug but not too tight. I think the Versalite would be too big. 59 inches of girth is about as tight as I can go and still wear all my clothes and move my arms. Maybe an inch or two tighter would be OK, but not larger than 59 inches. I'm 5' 11', 160 lbs, size 42 coat, cold sleeper. Thanks for the feedback.

I am with you, Coin, on the center zip over the chest location. My LuxuryLite V Bag has a full-length center zip and as a side sleeper I don’t ever want to go back to a side zipper. Here is what Nunatak says about the center zip Alpinist.

“First we moved the zipper from the side to a center front location. This gives you full use of both arms while still having head and back in the sleeping bag, a must when performing camp tasks in less than ideal conditions. The center zip also gives you more effective torso ventilation. Sleeping on your sides is also more comfortable since a zipper on your shoulder sucks.”


And a full-length center zipper puts the hood in a better spot when I use the V Bag as a quilt. So the next question should be; would Nunatak custom work include doing a full-length zipper? And if WM doesn’t do custom work what about Feathered Friends? They have bags with shorter center zippers and they do custom work, so why not full length?

And then there is the cost of custom work? You can have anything you want if you can pay for it. My V Bag is a keeper-I have posted a detailed Reader Review on it-but I want a larger center zip winter bag.

My wife has the WM UltraLite (short) which fits her just fine at 36" chest. I myself have the WM MegaLite (long) which is about as tight as I want with my 44" chest and 6'-1" height.

Thanks for the tips. One other feature I'm looking for is a subdued color, like grey, for "stealth" camping and airing. Thats my main problem with the WM bags. I'm thinking about
Feathered Friends, but as Allison says above, I would be pretty much stuck with it. I prefer the hood not contoured, so it will lay flat as a quilt. The Nunatuk bags seem to have a sculpted shaped hood.