question what to look for in a survival blanket are their ones better than another one and what to look for when buying one.
First of all, welcome! As to your question, that's going to depend on several things. Space, size, weather conditions, and if your wanting just warmth, or emergency shelter from the elements! A good Mil. Wool blanket is a seriously handy item to have, but they are heavy and take up space. A "Space Blanket" offers some warmth, and takes up litttle space. There are many types and brands, some better and some a gimick! Im quite sure there is a thread here some place covering both types so dig in and have a looksee!
The usual and preferred means is a wool blanket covered with a reflective cover. A bare reflective (foil) space blanket commonly sold as a survival blanket will suck the heat out of you faster than bare skin. Even if wet, wool will keep you warm in winter, and evaporative cooling will be useful in the summer. We have several easily found threads on blankets. Here is one thread on wool. Gear Review - 100% Wool Blankets (Master Listing)
Old school, casualty blankets like the military use are durable and can be used for a lot of things, bivy, tarp, ground cloth but I don't really use it to stay warm or dry, etc. Found that I prefer using a poncho and liner, plus wool blanket for warmth and protection from the weather. The light weight ones are cheap and handy in a light weight emergency bag, but they have never lasted long enough for me to really use one for any time in real life, but I am old school. Sitting in a car on a seat so not in contact with the cold ground and not keeping water off, the cheaper ones would be handy.
I have always had Pendelton Wool Blankets.... Yea they are NOT Cheap, but they ARE the Cadilac of Warm Blankets...
This may be a little on the weird , what the hell you talkin' about side . But in keeping with the purpose of this forum , and multi purposing materials , I'll throw this out there . A few years back , I was building a house , and in my material list to the lumber yard , I requested a house wrap , which goes on your outside walls , before your final siding goes on . It's basically a waterproof barrier to prevent water intrusion to your wood sheathing or studs . If your not familiar with brands of house wrap , think about , or google Tyvek . Well the house wrap they sent me was a roll of thin foam , maybe an 1/8th inch thick . The day I was installing the wrap was probably around 75 -80 degrees . When putting this stuff on the house , we had it stretched out across the house ,and my helper dropped one end of it and it fell down and covered me up in it . Once that stuff fell and covered me , within a few seconds , the temperature jumped 10 -15 degrees . I got out from under that stuff as quick as possible . But , at that time I thought that that would make an excellent blanket for survival in a pinch . Not that your just going to find it laying around everywhere . But for retaining your body heat and water repellent , I thought it would be great for a temporary fix . But , you would not be able to stay completely covered in it , as it is not a breathable material . It definitely will be lighter weight than a wool blanket . and I am definitely not nocking the wool blanket , I love them , but just throwing out something to remember , just in case .
Bubble wrap is pretty much the same way. Large enough portions of the bubble wrap and you can stay plenty warm in "your own heat " It does not breathe but the air barrier insulation factor is great except that you must have the discipline NOT to sit there in pop the bubbles . In the winter we put it either above the top sheet or below the bottom sheet but never both , sweating seems to undo the benifits .
I keep an SOL Heat Sheet in my pack with some cordage for in case. It is small and more rugged than the plain mylar ones. https://www.amazon.com/dp/B001MVZRSQ/?tag=survivalmonke-20 The military casualty blanket folds down to about the same size as the Heat Sheet and is even more robust. I have a bunch of those around somewhere. Mainly use those for ground cover. I have found that when I used to keep it in my pack, it would develop tears on the folds. But good enough. If you want to go to the other extreme, a Jerven is super robust and bulletproof. It has a 10 year guarantee too. But expensive.
The toughest plastic material I know if is boat shrink wrap 9 mil . This stuff stands better through the winter than any other tarp material you can find. Boats shops that do the winterization and shrink wrapping will sell it by the foot, and I stow it behind the seat while driving great stuff. It stands up great for a tarp covering equipment in out side environments several years, and tough enough to make a tent or skin a canoe , top of that and it can be welded to its self with heat ,of course it also shrinks with heat too . It is not an insulator but it sure works to keep the water out.
