How do Emergency Blankets Work?

On the side of the mountain or a snowy tundra, the risk of hypothermia can be extreme and the consequences high.

We do what we can to prepare for the moments in which our body heat is being pulled from us rapidly, but there is little you can truly do to stop it.

Emergency blankets are one of the best options to bring along in case coming across a true cold emergency. 

There’s no way these thin, aluminum-foil-looking sheets of material can truly keep you warm, right?

They barely have any substance to them and aren’t exactly what you would pick when you lay down on the couch to watch a movie in the winter.

These compact blankets are the result of years of expensive research put on by NASA, and they will surprise you in the most desperate moments. 

So, these blankets are going to be able to possibly save your life. But, how exactly do these emergency blankets work?

Unfortunately, there’s no true magic coming from Hogwarts or Narnia, but the science behind it is incredible. 

Blankets Made for Space

The emergency blanket that sits, neatly folded, in your preparedness kit didn’t come from an old grandma weaving wool like most other blankets. Instead, the origin story for this blanket is from NASA nack in 1964. 

When a broken heat shield occurred in a mission on the Skylab, engineers rushed to find a solution and came up with this thin sheet of aluminum material.

The original intended purpose of the “blanket” was to reflect heat away from the Skylab and prevent it from overheating.

It turns out that the aluminum sheet was incredibly effective and is still used in space missions to the day. 

When people began to see how effective these blankets are at keeping heat out, they tried their luck using them to keep heat in.

They trap heat that is radiated from the wearer’s body and reflect it straight back at them.

This emergency heat shield quickly turned into a mass-produced “blanket” that has found uses from inside hospitals to the finish line of a marathon.

The Science

The technology that started the discovery of the emergency (or space) blanket was first used to make tinsel for Christmas trees and other decorations.

That’s right. The shiny decorations that you’ve been putting up in December is basically a strand of shredded-up space-age technology that cost millions to develop. 

The process itself is called metalizing. A thin plastic film acts as the base for the blanket and vaporized aluminum is then applied to coat it.

This makes the result, a hyper-lightweight, thin, flexible, and compact blanket that can reflect infrared energy incredibly efficiently.

When we are talking about infrared energy here, we just mean heat. The sun puts it out, and so does our body.

Most materials that keep us warm work to trap this energy and hold it close to our bodies. The emergency blanket is like a mirror for this energy.

It bounces it straight back to the skin it came from and very, very little escapes. 

While aluminum is a good conductor of heat, the plastic that is used as a base for the blanket conducts heat rather poorly.

The heat on the inside of the blanket next to your body is less likely to be sucked out through the blanket and off into the abyss. 

The emergency blanket also acts as a barrier to the outside elements that are trying to take our heat away.

On a normal day, you can feel the breeze and the resulting windchill that follows. The aluminum-plastic barrier is impermeable, meaning it doesn’t let the wind through.

This stops the possible heat loss coming from the weather outside. 

A lot of emergency blankets you find have two different sides. One side is the shiny aluminum silver or gold finish, the other side is a green or orange color.

When you’re using the blanket to stay warm, the shiny side needs to face your body as it is the best to reflect heat.

The opposite is true if you are attempting to keep the sun away.

For example, a shade shelter constructed from an emergency blanket will have the shiny side being the roof. 

Why an Emergency Blanket?

If you’re putting together a preparedness or a first aid kit, there’s no reason why an emergency blanket shouldn’t be included. Most blankets weigh in at around 3 ounces and fold down to the size of a deck of cards.

The benefits you can get from having an emergency blanket on hand far outweigh the weight you will carry with you. 

On top of that, an emergency blanket is an extremely low cost from any dealer.

Maybe back in the day, they were expensive, but only because they were being made for actual space exploration.

Today, you can get them for almost nothing and go on your own exploration.

For a product that’s so compact and low-cost, the number of uses is outstanding. We’ll go quickly into a few uses that we have only briefly touched on. 


An emergency blanket is going to be crucial to helping prevent hypothermia and can be used alongside a heat source to rewarm someone as well.

If you make a successful hypo-wrap, you can incorporate an emergency blanket as the first layer to trap the heat the body is still producing. 

As an additional measure, you can add a bottle of heated water, HotSnapZ, or hand warmers inside of the blanket, and that heat will radiate to the entire body. 

Survival Shelter

In the same ways the blanket keeps heat in, it will reflect heat out.

An emergency blanket can be used in a hot environment to provide shade and even more protection from the infrared energy the sun puts off. In the desert, this can mean the difference between life and death. 

Marathon Running

At the finish line of a marathon, you may often see a lot of runners wrapped up in these emergency blankets. When a runner starts a marathon, their body temperature will quickly drop to compensate for the heat being produced by running.

At the finish line, it takes time to get their body temperature back up, and to prevent any further heat loss, an emergency blanket will retain the heat that is being put off by the burning of calories. 

Hospital Use

Anesthesia has a side effect of lowering the body’s core temperature and can result in shivering. As you can imagine, surgery isn’t the best time to have the body shivering and moving around.

To prevent this and keep the body warm while operating, doctors use emergency blankets on the patient throughout the surgery. 

Emergency Signalling and Firestarting

The aluminum side of the emergency blanket not only reflects the energy and heat but also will effectively reflect light. This can be used to create emergency signals if you are attempting to contact someone in the air. 

The same concentrated light can be used in a similar way to a magnifying glass to start a fire. Learning how to start a fire without matches is another important and handy survival skill to have under your belt. 

In Conclusion

There are a vast number of ways that an emergency blanket can come in handy when you’re faced with a difficult survival challenge.

If you can avoid the common misconception that these blankets will provide heat and understand the ways they truly work, your use of the blanket can be lifesaving.

I highly recommend getting a few of these today and throwing one in your bug-out bag, one in your first aid kit, and maybe one in your car. You’ll thank yourself later. 


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