Pete,

That makes very good sense to me, and I hadn't seriously thought about that way of using the mylar. I think that for short duration - up to roughly overnight in below-freezing temps - that would be the best way to go.

For longer duration, it seems to me that two mylar sheets might be better - mylar, insulation, mylar, and roll up in the package so there is mylar protecting the insulation from both exterior factors (wind and rain/snow) and interior factors (primarily insensible persperation). Hmmm. I might give that a try. Maybe my Tyvek ground cloth (outside layer), a poncho liner, and a mylar sheet (inside layer), since I carry all three of those anyway.

Regards,

Tom