When it comes to emergency preparedness, most people know that you should always pack a space blanket or emergency blanket. We see the rescues on TV with shivering people all wrapped up in alfoil sheets. But do space blankets work? Or are they just a waste of money? In this blog post, we examine the fascinating facts behind space blankets and find out if they’re really worth packing in your survival kit!

What is a space blanket?

A space blanket is a thin sheet of reflective material that is used as a type of blanket or cover to reflect heat. They’re also known as ’emergency blankets’, ‘thermal blankets’ or ‘mylar blankets’.

It’s called a space blanket because it was first used in space. But space blankets are not just for astronauts. They now have a tonne of more common uses.

Space blankets reflect heat around them. They don’t provide warmth or insulation.

Do space blankets work?

The short answer is yes they work. But not the way you think.

They don’t provide thermal heat like wool does.

Instead, space blankets prevent radiant heat loss by trapping your body heat.

They also slow down evaporation (of your sweat). Evaporation cools the body and a space blanket will delay this cooling process.

Finally, they’re wind proof. So they prevent wind or breeze from cooling you down too.

If you’re in an emergency and need to warm up, it’s best to use a space blanket with other forms of warmth. We explain how below.

What is a space blanket made of?

A space blanket is made of a thin space-age material that has been coated with a heat-reflective substance.

The material used in space blankets is metalized polyethylene. Polyethylene is just a type of plastic but it’s used to make the space blanket durable and weather proof.

A thin layer of reflective aluminium is applied to the top of the plastic. This is what gives a space blanket its reflective abilities. The reflective coating reflects 80% to 90% of body heat.

They can be wrapped around the body to create a barrier between the cold air and the body, trapping heat and helping to keep the person warm.

So space blankets are made of the same sort of material as mylar bags are. That’s why they’re often called ‘mylar space blankets’ or ‘mylar thermal blankets’.

Space blankets are also called emergency blankets, as they’re commonly used in rescues or survival situations.

Who invented the space blanket and why?

NASA invented the space blanket. They were looking for a way to keep astronauts warm in space.

What is a space blanket used for?

NASA first used space blankets in space to help with heat retention. For everything from space equipment to the astronauts themselves.

These days, space blankets are commonly used first-aid in situations. Rescuers and ambulances carry them. They use them to help restore body temperature of people exposed to elements. For example, rescuers will wrap a space blanket around someone to prevent or treat hypothermia by reflecting heat back to the body.

Campers, hikers and fishers use them in their camping packs, for a bunch of things we’ll go through down below.

Survivalists and emergency services recommend you put one in your emergency kit for when things go wrong.

Space blankets are also used by athletes after a race or workout, as they can help the body to recover from the exertion more quickly.

What does a space blanket do?

A space blanket reflects radiant heat and blocks heat escape for whatever is inside or under it.

In addition to their use in cold weather, space blankets are shiny gold or silver in colour and can also be used to reflect heat in hot weather.

How does a space blanket work?

Humans lose heat in 5 ways: Convection (wind), Conduction (contact with wet or cold surfaces), Radiation (heat loss emanating from your body), Evaporation (sweat or perspiration) and Respiration (breathing).

A space blanket won’t address all of these so must be used together with other items if you want a complete heat loss system.

A space blanket will block radiant heat loss. The material from a space blanket is made up of many layers of very thin plastic. The spaces between these layers are what trap heat, which is then reflected back to the body. By reflecting back the body’s own heat, the space blanket prevents that heat from radiating out into the environment.

If used correctly, it also traps the moisture inside which slows down heat loss from evaporation.

The material in a space blanket will also protect against convection heat loss. The blanket won’t let wind pass through to your body.

How to use a space blanket correctly

Manufacturers will best explain how to use a space blanket correctly in a survival or emergency situation. Here are the steps to follow:

1. Unroll the blanket and lay it flat on the ground, preferably on a warm, dry and insulating surface.
2. Lay on the blanket shiny side up, leaving about 12 inches of blanket overlapping your feet.
3. Fold the end of the blanket over your feet, and bring the two sides up together up over your fee so you’re wrapped in an envelop.
4. If you can, tape the blanket down – the better the seal, the more efficient the blanket.
5. Do not wrap too tightly; the trapped air helps to keep you warm.
6. Cover as much of your feet, hands and head as possible
7. Use another blanket to wrap around your head, leaving just your nose and mouth uncovered.

Manufacturers will say that in an emergency, space blankets are most effective when placed directly on the skin, and if required, other blankets may be wrapped around the outside. There is a lot of conjecture about this among emergency professionals and survivalists.

If you’d like to know more, here’s a great scientific write up about the physics of how space blankets work.

What are the benefits of using a space blanket?

Their poly and alfoil construction makes space blankets thin, waterproof and durable (good quality ones anyway). Lets look at the benefits each of those features brings:

1. They are thin so that they can work efficiently when compared to other blankets you might pack in your emergency kit. They are also lightweight and easy to carry and store, so they are great for emergency carry kits like Bug out Bags or Get home Bags.
2. The poly does not allow water or wind to pass through it. So space blankets can protect you from the elements. You can use them as a wind break or a makeshift rain cover / poncho.
3. Good quality space blankets do not tear easily. The material is very strong and durable. This makes them suitable to use for a makeshift shelter or as a ground sheet to avoid the damp.
4. They reflect heat, so you can wrap them around yourself to keep you warm in cold weather. Or you can use them as a shade to reflect the sun’s heat away from you, to cool you down in hot weather.
5. They reflect light, which means you can use them to signal rescuers for help.

What are the downsides to space blankets?

Before you decide to buy a space blanket, it’s important to know what it’s like to use one. Here are some things you might expect, to the downside:

1. Because space blankets are made of mylar material they doesn’t breathe. It keeps moisture in the air. If your clothes are wet, the space blanket won’t absorb that moisture out them for you. It won’t help you dry out. Instead, you’ll still feel clammy and wet. Something like a wool blanket is better for absorption.
2. It’s lightweight, which means it can also be difficult to secure around you when there is wind about. You’ll need to tape it around you or you won’t be able to multi-task.
3. It’s a sheet, which means it’s going to leak warmth and let in chill, because it’s not enclosed. Space blankets leak warmth at your upper and lower body extremities. Below we talk about some alternative applications of space blanket technology that perform better in this area.
4. It’s also made of plastic and foil. It’s noisy and crinkles when you move like a bag of crisps. So using a space blanket will not give you the most comfortable nights sleep you’ve ever had.

Are space blankets worth it?

Despite some downsides, space blankets are absolutely worth it! They’re not just for astronauts! They have multiple emergency and survival uses. Because of this they’re an asset in difficult or tricky survival situations.

If you’re putting together an Get Home Bag, Bug out Bag or Australian Bush Survival kit, here are 6 reasons why we think owning a space blanket is ‘worth it’:

1. Space blankets reflect heat, so they can help keep you warm in cold weather.

2. They can also help keep you cool in hot weather by reflecting the sun’s heat away from your body.

3. Space blankets can be used as emergency shelter in case of a natural disaster or other emergency situation.

4. They can also be used as a ground cover on top of a sleeping pad or makeshift thermal bedding when camping or in an emergency. It will help keep moisture out (but not insulate against the cold ground).

5. Space blankets are lightweight and compact, so they are easy to carry with you in case of an emergency.

6. They are also inexpensive, and they are a good to have when you need to provide for warmth and shelter in an ‘essentials only’ affordable emergency kit.

How do space blankets work best?

Space blankets work best in conjunction with other items with thermal properties – like a woollen blanket, clothing or a sleeping bag!

The space blanket will fulfil its role reflecting your radiant body heat back to you and keeping out the wind and rain. Your sleeping bag or woollen blanket will provide dry thermal warmth and comfort.

7 ways to use a space blanket in emergencies or when camping

One great thing about space blankets? You can use them in multiple ways! Here’s a creative list of how you might use one, in an emergency or out camping:

1. Wrap it around your torso to restore your core body temperature when you are exposed to extreme cold
2. Use it as a liner inside a sleeping bag in extreme cold
3. Wrap it around a bed of leaves and twigs, to avoid rising damp
4. Use it on the outside of a woollen blanket to keep out the wind and rain when you sleep
5. Create a screen to reflect the heat of your camp fire back towards you and your shelter.
6. Use it as a wind break for your shelter
7. Line the windows with it to reflect heat or cold if stranded inside your car.

5 features to look for in a space blanket to get the best bang for your buck

The better the features in a space blanket, the more use you’ll get out of it. And the more useful it will be in an emergency! If you’re adding a space blanket to your Bug out Bag, bush survival kit or Get Home Bag, look for these features:

1. Size – bigger is better because you can use it as a blanket or to make a shelter. We recommend a size of 7 feet by 5 feet (2.13m x 1.52m).
2. Thickness – thickness equals durability. If you want it to last in rough conditions and not tear, get one a thicker space blanket. Most on the market are 1mil thick. You can get them up to 2.5mil thickness.
3. Grommets – grommets are reinforced holes manufactured into the blanket. You’ll need grommets in your space blanket to make a shelter, a wind break or a reflector for your fire. You can thread para cord through the grommets and tie your blanket to nearby trees. You can’t poke a hole in a space blanket as this will make it tear – just like a packet of crisps!
4. Weight – the more lightweight the fewer pounds or kilos you have to carry in your emergency kit!

4 alternatives to space blankets for emergencies, camping and hiking

With some of the downside mentioned above, you may want to look at alternative applications of mylar technology, to help you stay warm in an emergency. You’ll find the same mylar technology used for thermal properties in these alternative products:

1. Bivvy bags
2. Sleeping bags
3. Ponchos
4. Sleeping pads

So if you have more to spend for an upgrade in comfort, a mylar thermal sleeping bag or bivvy bag might be a better fit for you.

Conclusion

Recap: Do space blankets work? The answer is yes! If used correctly, space blankets are an essential item in any emergency kit, and for good reason. They can help keep you warm in extreme weather conditions and can be used as a shelter from the elements. Make sure to get a good quality space blanket so that you can rely on it to meet your most basic survival needs. Add one to your emergency kit today!