i bought a brit army bivy from Springfields in Burton-on-Trent supposedly new and goretex. I had condensation inside at times even though i always kept my head outside of bag, on one occasion in the Black Mountains on a cold night the condensation inside actually froze solid and there there was a sheet of ice covering the inside of the top of bag, after that unpleasant experience i ditched it for a snugpak bivy. These army bivy's are commonly referrred to as goretex but i don't think they are, i think they are oficially called ''water permeable material'' or something like that, certainly mine did not have the usual ''goretex'' marked on bag that is usually seen on most things where it is used. I am of small stature and wondered at the time if this contributed to condensation as the army bags are quite big and there would be a lot of ''dead air'' in bag, the snugpak one is smaller therefore less dead air if you know what i mean. I used the bag correctly without inserting my head but often my sleeping bag was damp in the morning but i put up with it until that night when it froze solid inside, the freezing of the condensation would obviously restrict breathabilty even further. I have read other threads and plenty people seem happy with their brit army bivy's but i sometimes, not always, had condensation problems with mine, and it was indeed sold as a goretex one. I think maybe the weather variations plays a big part in their breathability and how much dead-air is inside bag dependant on your size, also if they are not actually goretex but some type of water-permeable-material are they inferior to true goretex ones, the snugpak one has fared better i have to say.
