I have questions about bivy sacks and condensation.

[gnwatts]

I am with denaliguide I think. Maybe I am missing something, but why use a bivy and tarp, and then need a heavier (by 1 lb) synthetic bag, just to justify the bivy?
You can get a minimalist 1 person tent that weighs less than 3 lbs, gives you room to sit up and store gear, keeps the tent fabric off the bag. My old single wall Garuda weighs in around 3 lbs, never had a serious problem with moisture (the bag might have light moisture on the surface, evaporates quickly) and I have only light weight down bags. I guess if you don't mind being cramped in a small bivy, all to save at most 1.5 lbs, it is worth it.
Than again, I am probably missing the point, as usual.
Greg

[archbishop]

I am with denaliguide I think. Maybe I am missing something, but why use a bivy and tarp, and then need a heavier (by 1 lb) synthetic bag, just to justify the bivy?
You can get a minimalist 1 person tent that weighs less than 3 lbs, gives you room to sit up and store gear, keeps the tent fabric off the bag. My old single wall Garuda weighs in around 3 lbs, never had a serious problem with moisture (the bag might have light moisture on the surface, evaporates quickly) and I have only light weight down bags. I guess if you don't mind being cramped in a small bivy, all to save at most 1.5 lbs, it is worth it.
Than again, I am probably missing the point, as usual.
Greg

When I did my first test night it was raining. The REI Bivy that I was testing has a mesh face. There is no covering, In order to keep the rain out you need some sort of covering at least over your face. I chose to use my poncho tarp as the covering. We're not really talking a full fledged tarp. The choice of bag on the first night wasn't me choosing synthetic it was me choosing the correct temperature rating.
The following week when it was much colder I did use my down filled bag and no tarp. (No rain.)
My final conclusion on this bivy is as follows. I wouldn't hesitate to use it if I was so inclined. It would get the job done. Now having said that you're right, I have light tents to, and shaving a pound or so just to sleep in a tight space over sleeping in a tent just isn't worth it for the most part. I say for the most part because there are two times when I might still take the bivy. 1. When I want to shed all the weight I can so I can carry more camera gear. (DSLR and lenses etc.) Or when I'm doing a quick over nighter and I just don't need the tent.
People keep commenting on my use of bivy AND a tarp. I can only imagine that said people aren't familar with the REI bivy in question and screen door face. On that same point, while it may be cheating, I don't really think of my tarp as a "tarp" It's very light weight poncho that just happens to double as a tarp. At least that's how I justify stashing it my bag. It's been my tarp covering over my hammock for the past several months and I really like having it.
Hope this clears up why I choose what I did, and why I did what I did.