Extending temperature range with bivy




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    Tyler EE

    I've seen people put the sleeping pad on the outside of a snug bivvy. I would imagine if you are a still sleeper it would likely work fine, but you may end up having to DIY rig something to keep the bivvy and pad secured together. In terms of the quilt if the bivvy is snug on you I would imagine the quilt will stay in place around your body, so that won't be an issue. 

    I would do some experimenting close to home and see what works. I'd be interested in hearing the results. 

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    Here's what I did:  Cut a slit 3/4 of the way down the bottom of a SOL bivy.  Using double sided carpet tape, added a 20" wide piece of kite grade Tyvek.  Folded over and taped a channel at the top for the draw cord.  With the increased diameter, quilt and pad fit inside the bivy and I think it adds considerable warmth.  I also think the Tyvek will wear better and extend the life of the SOL bivy.  But in the winter I use an added Z-Rest pad outside the bivy anyway.

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    Gretchen Becker (Edited )

    Actually for winter backpacking I would recommend using a SOL Emergency bivy or HotSac VBL by Western Mountaineering inside of your Revelation. What you lose in comfort you make up for by keeping hot air and moisture near your body. Read more online about vapor barrier layers/liners. Otherwise I really like using my Sea to Summit Reactor liners which may add about 10 degrees or so to your sleep system. The SOL Escape bivy might work inside as well, but if it is too thick consider these other options.

    Finally, don't forget that your sleeping pad might need to be updated for winter temperatures, which makes a big difference on frozen ground. There is the obvious option of the Therm-a-Rest NeoAir XTherm, but placing a Reflectix layer on top of your pad or adding a closed-cell foam pad underneath will keep you toasty (Gossamer Gear makes thin foam pads that are relatively compact but would add degrees to your system).

    I am a MN native also getting into winter backpacking with my 20 degree Revelation!

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    Tim Marshall

    Gretchen covered everything I was thinking.

    I just want to state how dangerous it would be to wrap your quilt in a waterproof bivy.  As mentioned this will create a vapor barrier trapping all body vapors inside.  You want to move vapor barriers as close to your skin as possible.  A light base layer between you and the VB is about all you want.  Everything inside the VB can and will get wet.  If you trap your quilt inside a VB it will get wet, this will eventually degrade its warmth and leave you in a dangerous situation.  VB next to skin, with insulation over it works great, never put insulation inside a VB


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