Sleeping w/Down Clothes instead of Bag or Quilt

I think it depends on what shelter you are in and what the weather is like. If it's windy and you're in a tarp I do not think you could possibly be warm sleeping in just the down inners. Though, it depends on what you have underneath them and exactly how warm you sleep. I would predict that system could keep you warm in the 40's at best though and that would include you wearing a nice hat and in at least a tarp tent as opposed to a tarp.

The alpine light jackets are warmer and weigh 11.3 oz according to Montbell. I think those would be more likely to keep you warm in the 30's though.

This is all speculation however as I don't own any montbell pieces and I use a nice fluffy sleeping bag (usually opened up like a quilt).

In my experience, you need some type of additional covering, if only to protect the down clothing. I use a bivy bag for this and extra warmth. I believe that a wind shirt and pants might suffice. As everyone is different, I suggest you try many configurations out in your own backyard under varying conditions to build a consensus for what works for you under specific conditions. There really is no wrong answer (only uncomfortable ones)
Mike

I'm just starting to experiment with the first setup (which looks like its pulled from my post on the SUL big three thread).

Here's my trip report with my initial test: http://crazyrunnerguy.blogspot.com/2009/07/ice-age-trail-baffled-by-shrubberies.html

I slept in an MLD bivy with a small ridgerest torso-sided pad. Temps likely never got below 50.

I like your proposed setup, but you do need a bivy or an enclosed shelter to block wind. Also, the hot socks look great, but could be overkill.

The goofy thing about sleeping in clothes, or integrating them with a half-bag, say, is that you run into a dilemna with the clothes. They need to be warm enough to keep you warm when you're at your lowest metabolic rate (i.e. sleeping), but they can't be so warm (read: heavier) that you can't wear them when you're awake. This is why the Nunatak Skaha Plus is packed with down (and more of it) than comparable UL down jackets/parkas.

Have you thought or seen the wearable quilts from JRB? I made the swap this Spring from using a UL bag/quilt +insulated layer. IME with both the Marmot Atom and the BPL UL 60 Quilt, I felt smothered and restricted wearing my Montbell UL Down Inner jacket and pants inside. Maybe I should have done my homework on that one. Now with my No Sniveller I have a sweet dual functioning quilt that has plenty of girth for side sleeping and additional insulation layers. I also added the omni tape, which I can use to really seal myself in there if the cold threatens. I feel the change has made my system much more funtional and simple. With the Marmot Atom (21oz) for example, + MOntbell UL Down Inner Pants (6.7oz)+ Down Inner Jacket (7.9oz)=35.6 oz's=2.2lbs. Ouch=( for a system that barely got me into the 30's. Now i can get into the 30's with 1 item. Im a warm sleeper, or so I thought, but my old system left me waking up more often feeling the chill. With my NS I sleep right through it all;if it gets warm i like to open it up and free my arms of legs. The No Sniveller has found it's way into both my SUL and UL gear lists. One of my favorite pieces of gear. Check them out=)

When I tried to sleep in something approx the same insulation as the montbell inner I was chilled when it was in mid-40s F. You experience might vary.

I would second the observation that a challenge is finding something that is warm enough to sleep in but not too warm for use when you aren't sleeping. The same clothing which are good down to 20F when I was standing around / doing very light work weren't warm enoufgh to sleep in at 40F. The other issue is that clothing designed has insulation all around… but you will compress ~1/3 of it when you lay down. You will get a better insulation / weight ratio using a quilt.

What's worked best for me has been clothing warm enough when I am engaged in light work (but not sitting still), and a quilt which goes over the clothing which adds enough insulation that doubles or triples the garments insulation. Double is the need between light work and sleeping, triple because I don't get up at the lowest temp… and if I am up I am working hard and therefore need less insulation.

–Mark

I'd say, no, it won't be warm enough. The MB Down Inner Parka has 2.1 oz of down fill. The pants have 1.9oz of down fill. So 4 total oz of down fill. A Western Mountaineering Highlite has 8oz of down fill and is rated to 35 degrees. It's a very narrow bag, so it's the closest equivalent to wearing your sleeping bag. Even if you account for the less material needed as you will literally be wearing your bag, I'm not sure that would make up the extra 4 oz of down.

At the least, you'd absolutely have to be in a bivy sack or tent to block drafts. Something enclosing like a bivy sack (tho it'd defeat the purpose) might add/seal in enough warmth to push the limits.

The JRB quilt Aaron suggesed would be great, or the Western Mountaineering Caribou or Megalite are both very, very spacious bags and would likely allow the stomach, knee up position. (Exactly how I sleep, and why I now use a quilt/bivy) The Megalite did for me when I tested it in the store, but I'm 5'10" 175lbs, and I'm guessing you're bigger. Both are pricey, but not too much moreso than the combination you're proposing.

Thanks for all the quick responses. To fill in some of the gaps, I typically use a TiGoat Ptarmigan Bivy with an SMD Gatewood Cape. I just picked up a NeoAir small as well.

I have a couple different mummy bags including a WM Highlite and the MH Phantoms (32 and 15). Only the Phantom 15 has any reasonable room to move.

I do most of my hiking and backpacking in Central Cali at sub 5000ft, so night time temps don't get extremely low. Daytime temps in this area, even in the dead of winter, are typically too high to wear any down clothing comfortably. So the down clothes being too hot wear in the day is of no concern.