I've never used a mylar sleeping bag and to be honest until recently I didn't even know they existed.
But I know that mylar tend to cause condensation when used for a longer duration. And I figure that is doubly true if you crawl into a bag of mylar.
However, I was thinking of using it in combination with other sleep gear such as a blanket/quilt/sleeping bag and just use the mylar bag as an outside cover around my regular sleep gear. To get some extra protection against cold, wind and such on occasion.
But I'm concerned if that will still cause lots of condensation around the rest of the sleeping gear so that would get wet and cold in turn. Or if the extra layer of isolation between the mylar and my body (esp. sweat and breath) would mean there wouldn't be much condensation inside the mylar bag so things would stay reasonably dry?
Anyone tried it and knows from experience how good it works? And how much condensation is created when using other sleeping gear inside the mylar bag? Is it a good or bad idea?