I used a bivvy bag for two very wet nights. The velcro tore away and it wasn't what I hoped for. It was trashed when I got home. You do sweat pretty good in them whether you use the vent or not.
It's a good idea but for 30 bucks I'd sooner put the cash towards a better light weight sleeping bag.
It's a good idea but for 30 bucks I'd sooner put the cash towards a better light weight sleeping bag.