Zipped-up in a mummy bag, I always felt very confined and I’m a side-sleeper so my face usually ended-up inside – filling it with water vapor from my breath. For at least the last year I have been using my mummy bags like quilts and have enjoyed the freedom and comfort.
A big problem was that my first bag weighed almost 4 lbs. It didn’t take me long to acquire a lightweight (21 oz) Western Mountaineering Caribou 35F bag – warm enough for most trips, I thought. Turns out that I’m doing more cold weather trips than I imagined I would, so a better winter solution was called for. It arrived in the form of a ZPacks 10 degree quilt/bag. I got the long & wide version (25 oz).
They most closely resemble a semi-rectangular sleeping bag, I suppose, and are available with either a zipper or loops for straps (or fully sewn-up for that matter) so they can be used like a bag or a quilt. I waffled between zipper and loops, finally settling on zipper thinking it might be useful at cold extremes. I regretted that shortly after getting the bag because I’m too fat to get the thing zipped-up anyway. Oh well, that can change. Feb 15 2013
Feb 20 2013 update: On the first morning of my first trip with this quilt, the low temp was 14.5F. By 3 or 4AM I was shivering regularly and couldn’t get back to sleep. Fortunately, I also brought my 35F bag so I pulled that over the top and was asleep within minutes.
In the morning I noticed that much of the down in the ZPacks quilt was gathered around the edges and realized I had neglected to shake the down to the center the previous night. I just wasn’t accustomed to having to do that. On subsequent nights I’ve gotten the down arranged properly and stayed warm, though I haven’t had a night below 25F since that first one.
Oct 24 2013 update: I didn’t make it clear in the previous update that the bag has no baffles to prevent side-to-side movement of the down. This is considered a feature since it allows the down placement to be fine-tuned for the temperature. I’m a side sleeper, however, and flop from one side to the other many times a night. This alone is sufficient to cause the down to migrate to the sides so on a very cold night I might have to shift the down back to the center a couple times.
Jan 21 2014 update: I’ve since experienced a 16 degree night and several in the low 20s. I wasn’t exactly toasty-warm but I wasn’t so cold that I couldn’t sleep either – it was tolerable. I do have to rearrange the down over my torso a couple times during the night. The down in the lower part of the bag seems to stay put better so my legs and feet have never felt cold.
I’ve also been experimenting with different mattress combinations this winter and my favorite for very cold temps (<25) now is a short-but-wide Therm-a-Rest RidgeRest SOlite under a small Therm-a-Rest NeoAir, with my lower legs laying on top of my mostly-empty pack. It seems to provide adequate insulation and padding without adding a lot of weight.
I have no material connection with any companies, products or services mentioned in this post.