If you could only carry one in your survival kit, which would be better to have...a space blanket or an SOL emergency space bivy bag?

I know you could use the grommeted space blanket to build a shelter and reflect the heat from a fire back onto you, but the bag would cover you completely and protect you from the elements.

Which would keep you warmer?

I haven't used the bag-style before, but I've found the blanket formation gives me some flexibility of use (rain cover, etc).

I usually carry the bag, figuring I could always slit it open if I wanted to use it as part of a shelter. Of course, you could always tape a blanket into a bag. I doubt there is a huge significant difference in real world use. Either one would benefit from improvised components to improve effectiveness.

I EDC a heatsheet blanket but I carry both in my kits. One for in and one for under. That said, I'm still a card carrying member of over-packers R Us.

I was "camping" two years ago with my son's elementary school, and one of the guys who was chaperoning along with me had apparently been homeless by choice for a 12 month period of time and learned how to sleep outside rather well, in all sorts of weather. Despite the constant rain for the duration of the trip, he slept in a bivvy bag on a pad - no tent!

He told me that he basically lived in the bivvy bag and it was "all you really need"

EDIT: it was one like this:
http://www.campmor.com/outdoor-research-...ci_sku=81533BLU

That "bivvy" is a borderline tent, both in cost and weight. A "true" bivvy would be about one-quarter of the weight, and easily one third of the cost. What is nice is that there is a continuum ruanging from 8 ounce bivvy sacks on up to one person tents weighing about 24 to 32 oz (and higher). You can pick whatever suits your fancy and circumstances.

My reasoning exactly...



This is where I start to disagree... Taping a blanket into a bag isn't something I would plan for. Fumbling with flimsy heat sheat material and tape when it's raining, blowing and my hands are shivering... Nope, not my kind of fun. This is exactly when a pre-made bag really would shine.

If I could only carry one, it would be the blanket just because of the flexibility, especially if it is a bright color for signalling.

Blanket: Smaller, more likely to have with me. Some models have grommets, making it easier to user to make shelter instead of using as a blanket.

Bivvy: Warmer and easier to use for sleeping. Can be converted to blanket with a knife.

For me, the bivvy is too big to go in an on-body kit but I do have one in my BOB.

Can I choose emergency poncho?

A space blanket is really a small lightweight tarp IMO. Its utility comes from being cheap and lightweight.

I am more worried about getting rained on than much of anything else. Space blankets and bivys do not make very good ponchos, while a poncho can be readily pressed into the same kind of service as a space blanket, at a slightly higher weight and volume price.

A bivy cannot be readily used as a poncho either, although I suppose one could curl up inside one and wait out a rain shower.

In frigid conditions, the bag is going to keep you much warmer.

i'll go with the blanket.with a fire going,a big one,and the blanket as a lean too shelter you could stay warmer and dryer than just being out on the open with any heat from a fire reflecting off the bag.with the blanket you could move around to feed the blaze and sit or lay on some sort of heap of ground cover that would dry out from the fire.the trick to a reflector fire is to make the back logs really high and wide,like hip high at least and as wide as the lean too.

Since traditional mylar space blankets are so fantastically lousy, and the AMK polyethylene Heat Sheets & bivies are so much better, we should drop the mylar items completely from the discussion. The comparisions aren't really worth the bother regarding mylar, whether it is a sheet or a bag.

It's like evaluating "hatchback vs. small sedan?" and including the Ford Pinto in the mix.

i swapped out a foil bag for the Heat Sheet bivy from the good reviews i got on this site.it fits in my PFD and takes up no more room than the foil one and i can get a head net into the sack in comes in.
OK..about those Survival Blankets.i have not tried out the AMK sheet yet and i always take two of the Survival Blankets,with the mesh,on every canoe trip.for my needs they work just fine but i'll put the AMK on the list of things to try out.my local gear shop will have a $10 gift card along so i can buy and try.

The Problem..with Mylar---



this one was exposed to dry heat when i used it under a water bed heater that was warming a vat of crushed grapes while making wine at home.the holes were the part that was not covered with the vat but in open air touching the heater...my fault.



this one was used as a floor mat in my Baker shelter.i had set pots of stew and other boiled items on the blanket with no problems but when i set a fry pan with a bannock right off the stove on it,yup--melted right through.i cut the hole square and use the blanket as a floor and the hole serves as a "cook hole",at least thats what i tell my fishing buddys---

if any one has AMK blankets that have stood up better i would like to hear about and maybe a photo.

I would certainly agree that the Heat Sheets are better, but I am recycling my mylars as footprints (groundsheets) for my small tents. They do quite well in that capacity.