Emergency aluminium bag as vapour barrier?

[JCB81]

Hey guys,

I'm off snow camping shortly and have found recently i'm getting bad condensation on the outside of my sleeping bag. I don't want to spend much or have the time to buy a fancy vapour barrier or clothing. So has anyone had success using an Emergency aluminium bag like this one, it only has to last 8 nights or so? https://www.kathmandu.com.au/emergency-v2-bag.html

I also own this bivvy bag that I could put inside my sleeping bag, but would it be too breathable as a VB? https://www.alpkit.com/products/hunka

Also I have heard of people using wetsuit booty socks to sleep in, I have a pair I might bring, anyone got feedback on this option?

Cheers

James

[nq111]

I've used the SOL emergency bivvy (non-breathable version) on several week-long trips as a vapour barrier and has worked fine. I've never seen the Kathmandu version but probably comparable. The Western Mountaineering VPL i have now is a little nicer to sleep in and more durable but I never had any tears or holes of note in the SOL.

The breathable bivvy isn't really going to work if you want a VPL.

Never tried sleeping in wetsuit bootie socks.

[Moondog55]

The combination of a VB and a breathable bivvy is well proven as they do different jobs but at the same time but a big plastic rubbish bag works just as well for use as a VB and is usually much cheaper.
I have also had good results using a partial VB such as a Tyvek SB cover or the breathable SOL bivvy, when using a partial VB you need to have the bag vented but the use of the liner usually makes the bag warm enough that venting can be a good idea. A full or partial VB is warmer than the use a normal liner because they work in different ways

[Neo]

The space blanket should go fine if loosely draped over the top of your sleeping bag so it breathes a little. I too wondered but haven't tried. Rain jacket works well.

Have been using a heavy duty space blanket as a ground sheet for a while.

Put the Alpkit as your outer layer, that alone should be enough of a condensation barrier, and cut any breeze.

[nq111]

The space blanket should go fine if loosely draped over the top of your sleeping bag so it breathes a little. I too wondered but haven't tried. Rain jacket works well.

No, sorry - you want it inside the sleeping bag so that it prevents your perspiration going into the sleeping bag and cuts evaporative cooling. Outside the sleeping bag may trap even more moisture within the sleeping bag and do little to stop evaporative cooling. May make you a bit warmer in the short term though.

[Neo]

Hmm my recent experience at 1800m -2 was as soon as the sun went down, or came up, the 'air' condensed and froze on everything exposed. So I guessed the condensation concern above would be coming from the environment or within the shelter..

Yep the bag needs to breath, but you would just sweat on your person if a space blanket was inside the sleeping bag. Any kind of loose cover on the outside should prevent your body moisture and the external air condensing on the outer of the sleeping bag, without inhibiting the bags breathability IMHO...

[Moondog55]

VB absolutely needs to be inside the SB

[JCB81]

I have just found a tyvek like overall in my house, has anyone used this to sleep in? It would be less noisy and more durable than the aluminium bag.

https://www.amazon.com/Kimberly-Clark-K ... B0085XUBKI

[Moondog55]

Never slept in one but surprisingly warm and comfortable. I see no reason not to give it a try