When the mercury drops, I still like to hike and camp. I really like settling down all cozy, dry, and warm in my bag each night.

But the mornings are different. The vast majority of mornings I wake up with noticeable condensation in my down bag. It's not uncommon for me to sit up in my bag, and where the crease is near my waist, visible water is forced out. Well, enough to make the shell fabric damp. I actually thought I spilled some water on my bag one morning.

It's also bad near my feet. I can just feel the moisture if I squeeze the footbox.

I can't find a pattern to when this happens either. I try to vent my bag as much as possible, but when its really cold, I have to zip up.

I'm using a Marmot Pinnacle 15F bag.

I'm normally not an overly-sweaty person, but I do tend to sleep warm.

Winter season is coming and I'd like to try and remedy this. Must I get a VBL system? Is this normal?

What kind of tent/tarp are you sleeping in/vents? near water or vapor?temps?

This is absolutly NORMAL.

You will ALWAYS have a little condensation on your sleeping bag. More in a tent than in an igloo.

As soo n as you get up in the morning - set your sleeping bag out in the sun - or breeze - or even light snow. Hang it in a tree, or on your skis.

Give your sleeping bag 20 minutes, it helps a LOT.

Some folks like VB liners, but I find they are a real-deal hassle. THe best solution I have found is using a super light synthetic sleeping quilt INSIDE or OUTSIDE your sleeping bag. The lightweight BPL cocoon is PERFECT.

On 99% of mornings I have zero condensation except for very mild condensation only on the footbox.

Bag- RAB quantum top bag (hoodless)
Sleeping bag cover- Equinox
Shelter- Golite Hut 1

Edited by jshann on 09/09/2010 19:20:20 MDT.

John, do you attribute your condensation-free mornings to your bag cover?

Mike, I'm guessing you're suggestion to use an over-bag to help push the dew point out of the sleeping bag?

Oh, forgot to add.... I either sleep in a Double Rainbow, or under a Trailstar. I try to pitch them open/high as much as weather and wind permit.

Edited by T.L. on 09/09/2010 19:22:49 MDT.

Condensation free (except footbox) due to bag cover and hoodless bag so there is no way I am accidentally breathing even slightly into the bag. The pertex quantum fabric of bag and good breathability of the equinox cover are also contributory. I am not an overly warm sleeper.

That was for three season (missed that part initially).

In winter I have used a neatsheet as sleeping bag cover (because equinox is not for winter) and get no condensation even on footbox, but maybe a little frost around the bag opening. I have only about 10 bag nights of winter experience though.

Edited by jshann on 09/09/2010 19:28:31 MDT.

Inside the bag: 38 C and 90% RH
Outside the bag: -10 C and negligible humidity
Guess where the dew point is going to be? Inside the bag of course.

It does help if you sleep cool instead. It won't kill you, but it will cut down the amount of water vapour you give off. That may help a LOT.

VBL works, but is a hassle. Try sleeping cool first, and do air your bag in the sun.

Cheers

I wonder how skurka makes VBL work so good, does anyone know a place where he discusses-perhaps a thread-his VBL solutions?

http://www.andrewskurka.com/advice/technique/vaporbarrierliners.php

Mike C.,

Can you elaborate on the reasoning behind a synthetic quilt INSIDE a down bag? I can understand it outside, because of migrating the dew point to the outside of the down, but how would this function well in reverse? I have a BPL Cocoon quilt, but it is too narrow in the foot-box to fit well outside of a bag, so I am keenly interested in what you have to say.

It does help if you sleep cool instead

By sleeping cool, this means not using a bag overly warm for conditions( a -10*F bag in 10*F temperatures), thereby preventing excessive sweating?

As I also tend to 'sleep warm', this would seem to be a point in favor of a quilt, which would allow some of this excesive heat to escape rather than be trapped in a sealed bag.

Can you elaborate on the reasoning behind a synthetic quilt INSIDE a down bag?

I'm interested in this as well. Except instead of using the cocoon quilt, I'd be using the Cocoon pants and parka. I really like the idea of wearing synthetic insulation to bed, as it makes getting up for those middle of the night bathroom trips a lot easier.

A VBL will help for sure, as will the other suggestions.

I'm a VB user, and looking from the opposite point of view from Mike and Roger (who are no doubt much more experienced winter campers than me, so this is just my opinion), I find it a hassle to get up in the morning and dry my stuff out before hiking. Mornings are stinkin' cold up here in the winter, I want to spend as little time in camp hanging around and more time moving to warm up. I use a VB system and this lets me do that. No hot drinks or cooked meals in the morning either - I just get moving.

Camping on the West slopes of the Cascades in any season can find you waking to 80% plus humidity and 45F-50F temps. Think cold steaming jungle :) Your perspiration and respired moisture simple has nowhere to go, let alone ground moisture captured under your shelter and condensed. Campsites can vary a lot too. I've had dew-soaked brush on the trail get me as wet as any downpour. That's why I leave down for my lightest bag for SUL "height of summer" overnight trips in my area. Getting the bag out in the sun/wind before packing and on rest stops is about all you can do once it is wet. There is virtually no direct sun on the west side of the Cascades in Winter and lots of drizzling precip, so the drying option is really a hallucination. Body heat will help with mildly damp insulation. Many a good bit of equipment has been fried around here while trying to dry near a campfire.

Answers? Ventilation, campsite choices, breathable but water resistant bag fabrics.

my questions is how to deal with down in periods of extended rain like Dale mentioned above

we get rain and humidity and possibly no sun for days on end here

Edited by bearbreeder on 09/10/2010 12:25:37 MDT.

In continuous damp conditions, a liter bottle of boiling water in the sleeping bag will drive out a lot of moisture.

VBL's are very helpful.

Synthetic overbags are luxurious.

A waterproof and breathable bivysack also helps move the
dewpoint outwards and keeps stuff dry (including the
pads) from external moisture.

In sub zero Cascade conditions, I may use all 4 things
together.

> By sleeping cool, this means not using a bag overly warm for conditions( a -10*F
> bag in 10*F temperatures), thereby preventing excessive sweating?
Exactly. If you are hot you will sweat. But there seems to be a temperature range where you can sleep comfortably while not sweating very much at all. After all, what is 'sweating' but a means for your body to cool off when it is too hot?

> Can you elaborate on the reasoning behind a synthetic quilt INSIDE a down bag?
Sorry, but I would NOT do this. I would put the down bag inside and the synthetic outside, in the hope that it is the synthetic bag which cops the dew point. That keeps the down bag dry - always a Good Thing!

The one place where what I am suggesting is not effective is when the synthetic bag is so heavy it squashes the down bag. Well, just don't take cheap heavy synthetic bags into extreme conditions.

Cheers

Roger-

What do you think about the view that down reaches a better
insulation efficiency when compressed to a certain point?

Here's a long shot, and I might just be grasping at straws...

But how does your body react when your top insulation (sleeping bag) is warm enough, but your bottom insulation (sleeping pad) is barely adequate? Does your body try to produce more heat to compensate for the coolness on your back resulting in excess heat on top?

I'm just wondering this because on the winter nights where I experience this condensation, I don't feel "hot." I usually go to bed warm, and sometimes even a little to cool for my taste, but never hot. And the few times I've tried to vent my bag, I just end up feeling cold.

Travis, yup. I've noticed that inadequate insulation underneath begets more sweat; although I might not feel particularly warm (or even a bit cool), if I think about it I can detect sweat up top. Confused me until I figured out it was because I didn't have enough insulation underneath. Better insulation underneath fixes much of the problem for me. I do also use VBL in colder weather.

Brad,
I used to use a BA Insulated Air Core, but have since switched to a Kooka DAM. I haven't tested the DAM in anything below the upper 20s yet, but I'm hoping it will make a difference this winter. Man, it'd be great if that solved this issue!