Mylar emergency blankets - any use?

[David M]

Mylar "emergency blankets" seem to be part of a lot of emergency kits but are they of any real use? Can they keep you warm in an emergency or could they be slept in? They also tear very easily.

[Franco]

The term emergency is a good indication that it will do the job but it is not meant to replace the everyday stuff.

So emergency food ration are , for example, not the kind of food you eat when you have a choice.
Going back to the blanket, yes it does keep a lot of your body heat in however you will likely get damp too from your own trapped perspiration and as you already know yes the aluminised surface will peel off with repeated use.

[ErichFromm]

You can get thicker Mylar blankets that can be used multiple times and are reasonably tear resistant, though obviously will degrade eventually.

As per Franco - the issue of condensation is a big one as you are effectively wrapping yourself in plastic. I used one recently while hammock camping, and by morning my UQ was quite wet. The blanket itself is fine still though after use - I now keep it folded up under the floor near the spare tyre for one of those "emergencies" you mentioned.

[walkerchris77]

I carry one in my main survival kit. Good for attracting attention if you're in trouble and reflecting heat. Never had to use it. (Like most of my survival stuff) but u never know .

[walkerchris77]

A bit about them

[Gadgetgeek]

In my opinion, worth having, and worth spending a few bucks on. I've used the cheapies, and had them turn to ribbons while opening them up, and I've used the AMK ones to keep me going in some less than ideal conditions. For me its light insurance, and combined with even a really small fire, can really boost your chances.

[Orion]

I have always carried these on longer alpine rock climbs and was glad I did a number of times. When you're caught out at elevation without a sleeping bag an aluminized (aluminiized?) mylar blanket or bivy sack is more than worth its weight. They do tear easily though. A big garbage bag is helpful as an adjunct or even as a bivy bag in itself, although plain polyethelene is less capable of limiting radiative heat loss. I once shared one of the mylar bivy sacks during a rainy night. I didn't think it would be possible for two adults to fit inside one of them, but it was.

Condensation is less of an issue than one would expect. The usual reason to be in one is because you'd freeze your rear off otherwise. And there's usually some movement of air no matter how tightly you wrap yourself up in the thing.

Polypropylene versions of these aluminized emergency blankets and sacks have been available for a number of years (e.g. Adventure Medical Kits). They are a tiny bit heavier but much more tear resistant.