Air is a conductor rather than a insulator. Most foam pads are all air. Very comfortable but all air. Closed cell foam is much better insulator. If a guy didn't want to use a gore-tex bivy, he could go to home depot and get a canvas drop cloth to cover up with. Canvas breaths. People are a bit concerned with spending money on sleep stuff but another way of looking at it is, and we've all been there, how much would we spend for a night in a motel when we just spent the entire night shivering and hardly got a wink of decent sleep? Bad sleep = bad next day.