Those mylar emergency blankets are just plastic with a reflective metallic surface.

The temps here have dipped lower than I'm used to, I haven't been getting off work until after 9 p.m., and the car heater takes a while to produce heat. I've got my coat and a knitted hat. I could still feel heat leaking through the hat. When I got home, I cut out a circle about a foot across from a blanket and put it on my head under the hat.

WHAT A DIFFERENCE!

Then I had to work in my friend's cold garage for several hours on a project, so I wore my two-layer hat. When I got home and took it off, the inside of the mylar was coated with moisture.

So, what is one of those mylar sleeping bags going to do? First it warms me, then it makes me sweat, then I die of hypothermia? Or should they just be used for wind deflection with plenty of ventilation?

Any real-time experience out there?

How about a perforated emergency blanket, aka WallyWorld Goretex? <img src="/images/graemlins/smile.gif" alt="" />

Sue