Bivvy Sack Blues -- The Case of the Condensation

[Hikin_Jim]

So, I slept out last Thursday night in the SGW overnight in sleeping bag and bivvy sack. The overnight low was in the 20's. In the morning when I woke up, there was a lot of condensation on the inside of my OR Aurora Gore-Tex bivvy sack. I had slept with the mouth of the bivvy fully unzipped. Are bivvy sacks just a bad idea in cold weather? I've not had this problem before in warmer weather.

I'd love to hear the experiences of others, particularly if there's a good work around.

HJ

[mattmaxon]

I have not had such a problem

I've used the Black Diamond winter bivvy and a newer one I just got.

I mostly use these in cool / cold weather

Matt

[Hikin_Jim]

I have not had such a problem

I've used the Black Diamond winter bivvy and a newer one I just got.

I mostly use these in cool / cold weather

Matt

And these are Gore-Tex I take it? And you had no condensation probs?

Maybe I'm just a heavy perspirer. I wouldn't have thought I'd have been sweating much since I was in a 32F bag in about 25F weather. I was a tad cold all night. Or maybe OR's product is somehow different. Argh.

HJ

[Taco]

Are bivvy sacks just a bad idea in cold weather?J

No, they're used in the cold more often than heat.

[mattmaxon]

The Black Diamond Equipment Winter Bivy is no longer available, but yes it has high tech breathable fabric

the one I'm now using is Black Diamond Twilight Bivy

They don't really show it in the photo but it has a screen so the bugs don't bite

10.7 oz with the stuff sack

Matt

[Hikin_Jim]

The Black Diamond Equipment Winter Bivy is no longer available, but yes it has high tech breathable fabric

the one I'm now using is Black Diamond Twilight Bivy

They don't really show it in the photo but it has a screen so the bugs don't bite

10.7 oz with the stuff sack

Matt

10.7 oz! That's phenomenal. Mine is about a pound and a half (approx. 34 oz).

I guess I should have gone with eVent or something instead of Gore-Tex. Sigh.

HJ

[Hikin_Jim]

Are bivvy sacks just a bad idea in cold weather?J

No, they're used in the cold more often than heat.

Dang. How do they do it? My bag was quite wet at the surface in the morning. No biggie for one night, but over multiple nights out, the bag would lose a lot of warmth.

Any tips for dealing with condensation? Maybe I need to punch air holes in my bivvy sack. Or just stick to temperate wx use.

HJ

[Taco]

I wish I could help you. I honestly don't know what to say. I don't really have much of an issue, other than some ice buildup inside the bivy bag sometimes. Maybe vent your sleeping bag more or less or something? See, I'm useless.

[Hikin_Jim]

ice buildup inside the bivy bag

That's exactly what was happening to me. And some of the ice would melt, wetting my down bag.

HJ

[Taco]

Maybe the solution at this point is to not use a bivy bag, and instead just use a tarp overhead, a tent, or none.

[Hikin_Jim]

Maybe the solution at this point is to not use a bivy bag, and instead just use a tarp overhead, a tent, or none.

Yeah, I'm coming to that conclusion, at least in cold wx -- time to bag the bivvy. I must just give off more water vapor than average. I've had the same problem with my old Kelty Dart I single wall tent. Serious condensation in cold wx.

A tarp tent would be great although they're a little pricey. Maybe a plain tarp would work; it certainly would be cheaper. A tent itself would be great, but generally I don't want to carry that much weight.

HJ

[EManBevHills]

I do use the foot zipper in my ancient Camp 7 sleeping bag to help ventilate.

[Taco]

Hell, I just use an old USGI poncho as a tarp! Can't afford that fancy stuff! Try one of them, make a hooch.

[Hikin_Jim]

Hell, I just use an old USGI poncho as a tarp! Can't afford that fancy stuff! Try one of them, make a hooch.

"Hooch?" I've heard the term by that was in the context of the Vietnam war. Got a photo or diagram of what you're talking about? I looked on the web, but there's a million things out there being called a hooch.

When I was "in" we used to snap a poncho lengthwise and slip our bag inside the resultant tube. Worked pretty well as a wind block and for drizzle or intermittent light rain. It didn't work well in thunderstorms or continuous raining-steadily-all-night rain.

HJ

[Taco]

Yeah, same ol' hooch, probably in the Ranger handbook if you've got one.

I use some bungee cords to situate it, tying off to some branches or whatever's in the area.

This is an example, though lower with more cover would be better in winter:




One poncho and one poncho liner on that shelter with a trekking pole holding the whole kit and caboodle up, 'cept the second pic which just has the poncho up.

[davantalus]

Jim, if you're willing to carry 1.5 pounds, you might as well be carrying a hammock.

[Hikin_Jim]

Jim, if you're willing to carry 1.5 pounds, you might as well be carrying a hammock.

I've got a Hennesy Asym, which I like, but it's a bit more than 1.5 pounds, and it is FAIL in cold weather. Yes, I could get an underquilt, but then I'd eat up any weight advantage that a hammock has over a tent. They're also limited where they can be used. I basically only use the hammock in places I know well, and then only in decent weather.

HJ

[Hikin_Jim]

Jim, if you're willing to carry 1.5 pounds, you might as well be carrying a hammock.

Oh, so you use the liner as part of your overhead cover? Interesting. I guess that'd work in terms of a sun shade, but I don't think that'd be so great in rain. And when it's cold, I want the poncho liner around me not up above me.

Interesting stuff, but I've read several places that it's better to get a tarp that is larger than a poncho otherwise you'll wind up wet if rains.

HJ

[He219]

10.7 oz! That's phenomenal.

Try 6.7 oz packed.



Used it keep my down bag dry for four years now, holds tough.

[Hikin_Jim]

10.7 oz! That's phenomenal.

Try 6.7 oz packed.



Used it keep my down bag dry for four years now, holds tough.

Looks good, and super light. A bit pricey, but I guess that's just how it is.

My problem with bivies is not water from the outside but rather water from the inside (condensation). How is this one with condensation in cold weather?

HJ

[He219]

My problem with bivies is not water from the outside but rather water from the inside (condensation).
How is this one with condensation in cold weather?

HJ

They use a proprietary system called Breeze Dry-Tec.
Works well for me, never had a problem with breathability in cold environments.
I've used it sleeping on ice from our Mill Creek Snowcave last year to multiple cold nights on Harwood, Rainier and Everest.

[Hikin_Jim]

Hmm. Very interesting. Not sure I'm ready to take the monetary bite just yet, but good to file away in the back of my mind.

My next acquisition, when I figure out a way to monetarily justify it in my mind, is a tarptent. We'll see.

HJ

[Burchey]

Hmm. Very interesting. Not sure I'm ready to take the monetary bite just yet, but good to file away in the back of my mind.

My next acquisition, when I figure out a way to monetarily justify it in my mind, is a tarptent. We'll see.

HJ

Jim, I know somewhere you can get a smoking deal on a GoLite Lair 1

[Hikin_Jim]

Hmm. Very interesting. Not sure I'm ready to take the monetary bite just yet, but good to file away in the back of my mind.

My next acquisition, when I figure out a way to monetarily justify it in my mind, is a tarptent. We'll see.

HJ

Jim, I know somewhere you can get a smoking deal on a GoLite Lair 1

Interesting, but that type still requires one to have a bivy (I just read a review) 'cause stuff blows in through the open front.

I'd like to get a Henry Shires tarptent which is supposedly the best of both worlds (tarps and tents), but I've got a Big Agnes Seedhouse 1 SL which is only a couple of years old, so I'm probably sticking with that for now even though it's a little heavy.

Bivies are nice, particularly for when you pull your car up to a trailhead late at night and you just want to roll out and crash. Just wish I could figure out how to eliminate the internal condensation.

HJ

[davantalus]

Just wish I could figure out how to eliminate the internal condensation.

They come in giant size too.

[Hikin_Jim]