Looking for a more breathable bag

[mattpage]

After a night in an Alpkit hunka I need something more breathable. The inside was soaking and the down bag was also wet through.
I'm considering getting something a bit heavier, more durable for non-race use, then something like a moonlight bag cover for the lightest, racing stuff.

How breathable is the Terra Nova discovery lite?
Or is eVent the only fabric to consider if I really want something breathable.

[composite]

Out of interest Matt were you under a tarp using the hunka?

Personally the only time I have found the hunka not breathable enough is when I didn't have a tarp and got caught in rain or if there was a particularly heavy dew.

[Ray Young]

Personally the only time I have found the hunka not breathable enough is when I didn't have a tarp and got caught in rain or if there was a particularly heavy dew.

That is my experience too. Or were you by any chance breathing into the bag?

[mattpage]

No tarp and also don't want to use one. The drawstring on the bag came out, so I was using it upside down.
I slept well, although I had very cold feet (another topic there!) but when I woke up everything was soaking.

[Bearbonesnorm]

It sounds like you had some of the worst possible conditions for condensation, I assume it was raining too?

There are quite a few things you can do to limit condensation but removing it altogether is a pretty tall order, here's a few. Some you might want to consider and some you won't.

Use a tarp, it'll shift the dew point away from the bivvy bag.
Don't cover your head, nose or mouth ... this is where a tarp's handy.
Try and sleep somewhere there's a slight breeze.
Don't get into bed damp or put anything wet in the bivvy in the hope of drying it out.
If you have to sleep directly on wet ground use a fully waterproof groundsheet.
Aim to be warm but not warm enough to sweat - a big, carb rich feast before bed doesn't help here.
Use the biggest bag you can ... more breathable area.

I've said this on a few occasions (so I might as well say it again) using a bivvy bag involves accepting a number of compromises and obviously trying to minimise them. No bivvy bag will do everything you want unless you're lucky enough to have perfect conditions but if you have those you probably wouldn't be needing a bivvy in the first place.

On paper eVent and Goretex just about offer the same levels of breathability, I'm an eVent type, others are Goretex. Something like a Discovery-Lite should breath very well but condensation will still form if the conditions are right and you're not able to alter your set-up to allow for them. Also, bear in mind that the majority of eVent / Goretex bags have non-breathable waterproof bottoms whereas a Hunka is breathable top and bottom.

Needlesports have an offer on Rab bags at the moment. I'd look at the Alpine and the Ascent. I'd go with the heavier Ascent as it's bigger and midge proof but it is heavier: http://www.needlesports.com/Additional- ... ial-Offers

Unless I can be 100% certain that it won't rain then I'll take a small tarp, any weight penalty can usually be offset by using a much lighter water resistant / highly breathable bivvy bag.

I'm not sure any of that helps

[Taylor]

With regards to the Rab Ascent, I bought one a few years back and whilst I liked it, I thought I could get lighter that would do the same job.
Three more bivi bags and lots of condensation later, I've settled on two different bivi bags.

A Borah bag for the summer, non wet nights and I went back to the Rab Ascent for the more inclement times of the year.
As Stu says, the only time not to use a tarp is if you can pretty much guarantee that it'll not rain/be dewy/etc.

I came close to selling my Rab Ascent last year, now I'm glad I didn't.

[gairym]

I've been a happy Borah user for a while now but in a stroke of luck came across a new Ascent bag for next to nowt recently and so will be trying it out this coming weekend - am expecting good things!

[mattpage]

Thanks Stu and everyone, great advice.

Better techniques required rather than better/new/more kit :)

[ZeroDarkBivi]

I used TN Dicovery on last years WRT. No rain (or tarp) but the down bag still got damp and I would only use a bivi on its own now with a synthetic bag.

[slugwash]

After a night in an Alpkit hunka I need something more breathable. The inside was soaking and the down bag was also wet through.

Disappointed to hear this. I was thinking of getting a Hunka 'cos I'm finding my Rab Survival Zone bag a bit wet in the mornings these days.

I've settled on two different bivi bags..........A Borah bag for the summer

I slept out in Brittany this Summer in just a sleeping bag and survived! In fact, before I had a proper bivi bag I slept out in snow in Winter and lived to tell the tale. I guess you only need the bivi bag if it's wet or very windy. I might even leave mine at home for the Ford Fiesta and see what happens.

[Bearbonesnorm]

Disappointed to hear this. I was thinking of getting a Hunka 'cos I'm finding my Rab Survival Zone bag a bit wet in the mornings these days.

If it's any consolation Rich, there's lots of folk who've spent the night in a Hunka and not suffered with condensation. I think at times we all need to remember that bivvy bags, regardless of make or model don't possess any magical properties

[FLV]

I'm experimenting with an MSR AC bivvy at the moment.

Lightish (450g), supposedly breathable, waterproof, has a mossie net built in, roomy
My intent it to use it without a tarp.
I'll be in it this weekend with no tarp.

I need to get more use out of it before I comment fully on its performance though.

[Dan_K]

Disappointed to hear this. I was thinking of getting a Hunka 'cos I'm finding my Rab Survival Zone bag a bit wet in the mornings these days.

If it's any consolation Rich, there's lots of folk who've spent the night in a Hunka and not suffered with condensation. I think at times we all need to remember that bivvy bags, regardless of make or model don't possess any magical properties

I've got a Hunka XL along with a Rab Storm (and a new TN Moonlite 2014 bag that i've not used yet).
Hunka's always been alright. In fact, on my last bivvy. I was in the Rab and suffered but the other 3 in Hunkas didn't. Great bag for money.

[Taylor]

http://40yearsofwalking.wordpress.com/2 ... conundrum/

[Zippy]

http://40yearsofwalking.wordpress.com/2 ... conundrum/

Aye, that was a good read when I went through this process.

In short my take is that a waterproof bivvy is a bit pointless coz once water is on it (on outside) it stops it being particularly breathable....