I recently re-read the Thunder in The Night blog about the value of using a synthetic quilt over a down bag in winter.

http://thunderinthenight.blogspot.com/2011/04/thunder-on-tundra-gear-sleep-system.html?m=1

I know this topic was touched on recently and in past years, and most people have positive things to say, but I was wondering if anyone has some Cons.

For overnight camping in the Cascades this winter, I'm debating between buying a 0 degree down bag or a MLD Spirit Quilt 28 to use over my 20 degree down quilt.

I like the modularity of the two bags but perhaps a single winter down bag might be better in terms of weight and compression.

Any thoughts would be appreciated.

Edited by whalen on 01/07/2013 09:23:30 MST.

My decision to use the synthetic over-quilt system linked to in the article above was based on the following article from some-time BPL contributor Jörgen Johansson:

http://www.fjaderlatt.se/2010/04/across-sarek-in-winter-sleep-system.html

We then completed a somewhat 'adventurous' six day ski tour of the Finnmarksvidda mountain plateau in northern Norway, including Arctic storms, falling in a river and near-death slides. Our sleeping system was the least of our worries ;)

I sue a slightly synthetic insulated bivy to move water. It also adds 15 - 20 degrees of warmth.

One concern that I have had is how much the outer quilt/bag would compress the inner down quilt/bag, either from weight and/or space restriction.

I have seen people squash a lot of the loft out of their down bag by piling a heavier synthetic quilt on top.

It was still warmer than the down bag alone, but not as much as you'd think.

Just need to be aware of this when trying this system.

@whalen

That would work...andy kirkpatrik endorses this system as well http://andy-kirkpatrick.com/articles/view/double_up

I am not a winter guru (mostly 3 season down to say 10F) but I do use an MLD 48quilt on top of my 30F or warmer bags. I think that maybe you should opt for a lighter quilt (like mine) and more of the insulation being in the down since that would be a more optimal weight distribution...

of course i am not sure i can prove that the dew/freeze point will be in the thinner synth layer...just food for thought. of course make sure you buy the wide version.

also - a feature i found useful when going this way (quilt over mummy bag) is to thread shockcord in zigzag through the gorsgrain loops in the MLD (see http://cache.backpackinglight.com/backpackinglight/user_uploads/1355327671_72658.jpg) so that i have an "elastic snug" fit over the mummy.
another trick i use is to do the same between the two loops at the neck - instead of trying to close the snap closure system that MLd have there...this way it easy after getting into the mummy while you are sitting to move this cord over your head and behind your mummy bag's 'neck" and you are done...(you can later cinch it a bit more around your neck)

MC

I think in winter, modularity is best. Managing your temperature is going to prevent you from overheating and sweating. Two pieces means finding that custom warmth, quickly, will be much easier. You can wake up cold four hours after you went to sleep, pull a secondary piece a little tighter, and go right back to sleep.

Just slept down to -10º a few nights using a 20º synthetic outer bag and a 32º synthetic inner bag. Total weight was a little under 5lbs, not super light but I don't have to buy another $400 piece to get under 4lbs.

I have done as Max stated. I will sleep in my three season bag and if needed pull the quilt on when the temps dip.

This allows me to keep from getting too warm, thus reducing moisture buildup from perspiration. Then when the temperature drops, I'll pull the quilt over.

pros ...

- your down bag is protected from internal and external moisture
- you can use your synth quilt in camp
- you can use the synth quilt in the summer
- you can dry the synth quilt much quicker
- you have more redundancy in wnter

cons ...

- a dedicated down winter bag will be lighter for the weight and more compressible
- a dedicated down bag will last longer than a synth quilt
- a dedicated down bag is less things to keep track of, but you do need to pay more attention to moisture
- a dedicated down bag is generally cheaper than buying 2 new bags .... but then you already own one so this is a moot point

at the end of the day if you are looking for a reliable way to supplement your sleeping system to deal with winter and moisture, without spending $$$$$ ... and plan on the occasional winter trip ... then the synth quilt is superior IMO despite weighting a bit more

youre more likely to get more use out of the synth quilt in the summer than you are the winter down bag overall, which is a very specialized piece of equipment

a 30-40F summer quilt will add about 15-20F to the temp rating of a down bag

for quilt over quilt ... youll need to find a way to deal with drafts of course ... and an appropriate hood

Edited by bearbreeder on 01/07/2013 13:06:31 MST.

Thanks for all the insight, truly. Everyone brought up some valid points, and despite the weight increase, it does seem that a synthetic overquilt would be the most versatile option, especially since the PNW summers can be wet.

I appreciate you taking the time to contribute your thoughts.

This was actually part of my reasoning in buying 2 different synthetic top quilts earlier this year. I will admit though, a majority of my reasoning was more towards moving the point of condensation to the synthetic top layer rather than in/on my down bag (Marmot Helium). The additional warmth would be welcome, but not my main goal.

I picked up 2 quilts from Tim at EE. One is about a 50 F quilt with only a single layer of 2.5 oz/sqyd Climashield Apex and the other is a 35 F Prodigy (a single layer of 4 oz/sqyd Climashield Apex). Both of these quilts are wide enough for me to simply drape it over my Helium and I would not plan to secure them in any way so that it did not compress any of the down in my sleeping bag.

However, I have not been able to test this theory yet... dang temps are ridiculous... The hike this weekend is calling for temps as high as 70 F... in January!