Double sleeping bag layers, which order?

[kitesurfare]

Hi guys,

I was having a discussion today with a friend about using sleeping bags in layers. I wonder if you guys would like to give me your opinions on the subject.

If a person has a 3 season Down bag and a 1 season synthetic bag and intends to use both together during the night (in a cold dry tent), which should be closest to their skin to keep a person warmest?

I say 3 season down, he says 1 season synthetic. what do you guys think?

 

[K9FORCE]

Caravan Combi...

Har inget med dun eller syntet att göra.
Däremot betyder storleken allt eftersom isoleringen beror på mängden bunden luft och inte vilket material som binder luften.
Anta att båda säckarna är precis lika stora. Då kommer den inre inte att kunna utvidga sig som den ska oavsett om det är dunsäcken eller syntetsäcken.
Om den ena säcken är större än den andra så ska den vara ytterst.
I annat fall blir problemet bara desto större.

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Has nothing to do with down or synthetic.
Size is everything since it's the amount of captured air that makes it warm and not the material itself.
Let's say that both bags are the exact same size. Then the inner bag will not be able to expand properly regardless of the filling material.
If one bag is bigger than the other, that bag should be on the outside.
The other way around will only increase the problem.

 

[kitesurfare]

spot on!

his summer bag is actually much larger than his winter bag : ) I know I should have mentioned that earlier

 

[K9FORCE]

Ok. Kollade lite på dina tidigare inlägg och insåg att det inte ska vara något problem att skriva på svenska.

Caravan Combi som jag skrev i rubriken på förra inlägget är namnet på en dubbelsovsäck som såldes för ca 30 år sedan. Den hade syntetsäck ytterst och dunsäck innerst.

Jag har för mig att motiveringen då var att syntetsäcken tålde mera stryk och därför hade man den på utsidan.

Speciellt i vår "småfuktiga" Skånevinter så är det nog en god idé att ha synteten ytterst om det går!

 

[kitesurfare]

agreed!

nice!, I didnt know they used to make bags in layers, but it does make sense : ) Thanks for writing in english and for the info!

Maybe I will try and get him out this weekend so he can try it out for himself : ).. I am a little restless, and now with 3 days off I dont know if I should go to Norway to get some snow camping done, or stay in Skåne for some kayaking/camping in Immeln : )

It wasnt so bad waking up last week when I was out : )

 

[magnus ul]

I think more about the weight of the bags, eg if I have two similar thick bags, I would put the heavy inside and the lightweight one on top.

If the heavy is the one on top it's just going to crush down the insulation of the one inside and take away half the insulation.

Just my two pennies

 

[kitesurfare]

thats a good point...

lets look at the idea in a different way... lets say we can choose to have a thin bag liner instead.. it would work better on the outside trapping the air in the sleeping bag, instead of having a thin layer on the inside right?

 

[shiloh]

I'm using a dual sleeping bag system myself. The sleeping bags are:

http://www.military-sleeping-bags.com/defence4.html
http://www.military-sleeping-bags.com/tropen.html

Tropen go on the inside. I think there was a -45C comfort temp and -60C extreme temp when using them together.

The Swedish army is also using a dual sleeping bag system. The thicker (3 season) sleeping bag is used inside the summer sleeping bag there.

Edit: Here was the info for the Carinthia sleeping systems: http://www.military-sleeping-bags.com/pdf/carinthia-catalogue.pdf

 

[lleberg]

The thinner bag inside, because it simply wont fit the other way around, and insulation wont work if its compressed!

But having a thin bag inside a warm one is so nice, it is completly drag-free, you can stuff it howerer you want depending on how you freeze and how you lie.. with a friend on one side and the tent wall on the other and so on!

I go with -14C wide down sleeping bag and my summer -0C lightweight down sleepingbag open inside, and i LIKE IT!