Do Emergency Blankets Really Work?

Do Emergency Blankets Really Work for Wilderness Survival? What 3 Studies Say

The mountains are notorious for their variable weather and afternoon thunderstorms. Despite all your best planning and regardless of what the weather forecast says, you might still get caught in a freak storm or shower. An emergency blanket supposedly protects from the elements in situations like this until help arrives – but do they work? Can a thin sheet of material that looks like aluminum foil keep you alive?

We cover all the facts and provide recommendations for emergency shelters that work in this gear overview for hikers, climbers, and backpackers.

Table of Contents

What is an Emergency Blanket?

An emergency blanket, commonly known as a space blanket, is made of a thin sheet of Mylar. This polyester material (often PET) is coated with a metallic reflecting agent, providing substantial thermal benefits. The polyester helps prevent tearing – while cheaper versions with only foil tear quickly and are often useless. While this construction may appear simple, the science behind it is designed to save lives, especially in survival situations.

By MABRU73 - Own work, CC BY-SA 4.0,

How Emergency Blankets Work And Keep You Alive

A mylar emergency blanket has three core functions to keep you alive in cold, wet, windy conditions:

  1. The blanket is waterproof and wind resistant to keep the elements out.
  2. The aluminum coating reflects up to 82% of your body heat back at you to keep you warm.
  3. The metallic or brightly colored coating can attract the attention of rescue teams.
That said, it leaves open an important question: with this design, do emergency blankets really work? Or are they more of a fad than an actually effective tool? Let’s take a look at what the relevant science says.

Do Emergency Blankets Really Work? Here's What the Science Says

Numerous studies have been conducted (more than 25) on the use and effect of an emergency blanket. Here are some of the biggest takeaways from these peer-reviewed articles.

Rescue Blankets-Transmission and Reflectivity of Electromagnetic Radiation (2020)

This study found that an emergency blanket provides UV protection but is transparent enough to still see through, making it an effective pair of emergency snow goggles for climbers. They also noted that a blanket blocks heat so effectively that you should remove it if informed by searchers they are looking for your heat signature. They noted that the blankets they tested reflected 82% of radiation back towards the wearer. Read More

Kranebitter H, Wallner B, Klinger A, Isser M, Wiedermann FJ, Lederer W. Rescue Blankets-Transmission and Reflectivity of Electromagnetic Radiation. Coatings. 2020; 10(4):375.

Rescue Blankets as Multifunctional Rescue Equipment in Alpine and Wilderness Emergencies—A Narrative Review and Clinical Implications (2022)

This article details the numerous ways you can use an emergency blanket for survival and first aid. It provides extremely valuable insights regarding the question, ‘do emergency blankets really work?’ This includes:

  • treating catastrophic hemorrhage and bleeding limbs,
  • performing open pneumothorax chest seals in sucking chest wounds,
  • preventing damage to unprotected eyes on glaciers and snowfields, and
  • alternative instruments for transportation in the inaccessible areas.

The finished by noting that “Rescue blankets are important rescue equipment in alpine and wilderness emergencies with multifunctional applications, and must be part of every personal medical kit.” Read More.

Wallner, B., Salchner, H., Isser, M., Schachner, T., Wiedermann, F. J., & Lederer, W. (2022). Rescue Blankets as Multifunctional Rescue Equipment in Alpine and Wilderness Emergencies-A Narrative Review and Clinical Implications. International journal of environmental research and public health, 19(19), 12721.

Efficacy of rescue blanket versus conventional blanket in terms of preventing accidental hypothermia during patient transfer by emergency medical service: a randomized clinical trial (2020)

This interesting study compared the efficacy of mylar emergency blankets with conventional insulation-filled blankets in an emergency services setting. They found no statistically significant difference in cold distress scores (CDS) collected across the two groups, suggesting that emergency blankets are an extremely effective tool for protecting yourself and others from hypothermia. Read More.

Saberian P, Sadeghi M, Hasani-Sharamin P, Modaber M, Farhoud A, Aghili M. Efficacy of rescue blanket versus conventional blanket in terms of preventing accidental hypothermia during patient transfer by emergency medical service: a randomized clinical trial. Journal of Emergency Practice and Trauma 2020; 6(1): 38- 42. doi: 10.15171/jept.2019.27.

An Emergency Blanket Will Help Keep You Alive - But You Won't Be Comfortable

Here’s a reality check: emergency blankets are built for survival, not for comfort. If you’re expecting the cozy feel of your blanket at home, you’ll be disappointed. Emergency blankets are awkward to wear, usually requiring you to hold them over or around you, making sleep difficult to impossible. They are noisy, crinkling with movement, and offer no padding or cushioning. Their primary purpose is to keep you warm enough to survive until help arrives. 

If you want something a little more robust, consider a bivy or other sturdy emergency shelter.

An Emergency Bivy is Heavier But Also Much More Comfortable and Durable

An emergency bivy is like a sleeping bag made of emergency blanket material – or for a reusable option, more durable materials. It offers an added layer of protection by completely enveloping your body. While it’s a bit heavier and takes up more space in your pack, a bivy provides superior thermal insulation, a little more comfort, and is often more durable for re-use. For those willing to carry the extra weight, it can be a more practical option in harsh conditions.

There are also non-emergency bivies that use top-notch waterproof, breathable material you can use anytime for camping or backpacking. They are heavy but offer a no frills backup if you run into extreme weather or get lost or injured on the trail.

The Best Emergency Blankets for Hiking: My Suggetions

Given what these studies and many others say, I recommend that everyone keep an emergency blanket or bivy in their backpack or first aid kit. An emergency shelter is one of the ten essentials for outdoor recreation. Below are four of my recommendations if you need to get an emergency blanket or bivy for hiking.

1. Best Overall: Arcturus Heavy Duty Survival Blanket - $22.99

This blanket from Arcturus is a lesser-known option that I tried and liked. The grommets in the corners allow you to use it to create a small shelter, and it’s durable enough to be re-used many times if you take care of it. 

While you can find cheaper options, the versatility of this survival blanket made it worth the investment and the small additional weight it adds to my pack. The bright orange color is easy for firs responders to see from a long distance.

Arcturus Emergency Blanket

2. Best Budget Option: SOL Emergency Blanket - $5.95

This simple emergency blanket is made using the traditional mylar design but with solid plastic backing that is tear-resistant and orange to attract attention from search and rescue teams.

While I wouldn’t plan on using the SOL Emergency Blanket more than once or twice at most, it is a much better option than the $1-2 options you can find online from many retailers, which quickly fall apart when used in the field. It’s a small price to pay for a sense of safety and security.

SOL Emergency Blanket

3. Best Lightweight Biby: SOL Escape Bivy - $48.29

This bivy is essentially a sleeping bag made of mylar material. It is much easier to wear and keep wind and rain out than a regular emergency blanket, but doesn’t provide much additional comfort.

Because the mylar material is coated in plastic, the bivy provides no ventilation and can get very wet if you don’t keep the top open and air it out periodically. In warmer weather, you can use it as a lightweight sleeping bag alternative.

SOL Escape Bivy

4. Best Group Emergency Shelter: RAB Superlite Shelter (4-6 People) - $130.00

This lightweight group shelter from Rab is built for mountaineering teams and rugged conditions. It has space for 4-6 people and their bags, with a bright orange color that makes it easy for rescuers to find. It doesn’t have any mylar, relying on body heat and wind resistance to keep you warm and reduce weight.

The shelter packs away into a small, lightweight bag you can slip in your pack and forget about until you need it. The shelter can only be used by a group, as it is held up by the group’s shared weight.

Screen Shot 2023-09-27 at 3.08.19 PM

When to Use an Emergency Blanket

In a hiking or climbing context, an emergency blanket or bivy (bivouac sack) should be used in situations where you need to retain body heat, provide temporary shelter, or signal for help. Here are some specific circumstances when you might need to use one:

Retaining Body Heat

  1. Unexpected Cold Weather: If you’re caught in a sudden drop in temperature and you’re not adequately dressed for it.
  2. Nightfall: If you are unable to make it back before dark and temperatures drop significantly.
  3. Altitude Sickness: If symptoms like fatigue, dizziness, and nausea force you to stop, retaining body heat becomes crucial, especially at higher elevations where it’s colder.
  4. Injury: If you or someone in your group is injured and cannot move, retaining body heat while waiting for help is essential.

Providing Temporary Shelter

  1. Stranded: If for some reason you can’t make it back to your starting point or a safe location, an emergency blanket can act as a temporary shelter against wind and rain.
  2. Forced to Bivouac: In a multi-day climbing or hiking trip, you may have to spend an unplanned night outdoors. An emergency bivy can provide better insulation than just a sleeping bag.

Signaling for Help

  1. Visibility: The reflective material of most emergency blankets can make you more visible to search and rescue teams.

Additional Tips

  • Wind Protection: These blankets can also act as a windbreak if you’re stuck in windy conditions.
  • Ground Insulation: You can also lay the blanket on the ground to add an extra layer between you and the cold or wet ground.
  • Tarp Shelters: If you bring ropes and have a blanket with grommets, you can use them to setup a simple shelter if conditions are right, below treeline.
Tarp and Emergency Blanket Shelter
How to Build a Tarp Shelter using an Emergency Blanket

How to Use an Emergency Blanket While Hiking

Knowing how to effectively use an emergency blanket or bivy can make a significant difference in a survival situation. Here are some best practices and tips:

For Emergency Blankets:

  1. Unfolding and Wrapping: Carefully unfold the blanket and wrap it around your body. Try to cover as much surface area as possible to keep the heat in. Make sure your head is also covered but leave space for breathing.
  2. Layering: If temperatures are very low, layer the emergency blanket with other materials like clothing or a sleeping bag for added insulation.
  3. Ground Insulation: Lay the blanket on the ground to act as a barrier between you and the cold or wet earth. This helps retain body heat and can make a noticeable difference in your comfort level.
  4. Signaling: The reflective surface of emergency blankets can be used for signaling in case you need to be rescued. Make sure the reflective side faces outward to catch the attention of rescuers.

For Emergency Bivy Sacks:

  1. Get Inside Quickly: Once you realize you’re in an emergency situation, get inside your bivy as quickly as possible to start retaining heat.
  2. Seal the Opening: Most bivies come with a drawstring or some form of closure. Make sure to seal this tightly to keep warm air in and cold air out.
  3. Use with a Sleeping Pad: For best results, use an insulating sleeping pad inside the bivy. This adds an extra layer of insulation from the ground.
  4. Ventilation: Just like with emergency blankets, condensation can be an issue. Occasionally vent the bivy to let out moisture, taking care not to let in cold air.

Emergency Shelter Best Practices

  1. Check for Tears: Before heading out, make sure your emergency gear doesn’t have any tears or holes that could compromise its effectiveness.
  2. Practice: Try using the blanket or bivy in a controlled environment before you actually need it. This will make you more comfortable and efficient in an emergency.
  3. Pack Extras: Due to their lightweight and compact nature, it might be beneficial to carry more than one.

By understanding these best practices, you’ll be better prepared to use these emergency tools effectively when it counts the most.

Do Emergency Blankets Really Work?

Do Emergency Blankets Really Work? Yes: An Emergency Blanket Could Save Your Life!

Despite what you might think, emergency blankets aren’t just a fad or scam. When use properly, an emergency blanket can keep you out of the wind and rain and retain enough body heat to survive until search and rescue gets to you. An emergency bivy provides even more protection and comfort, at a greater cost and weight to carry.

Whether you choose a blanket or bivy, it is always a good idea to carry some kind of emergency shelter when hiking, camping, or climbing in the Colorado backcountry. Safe travels on the trails!

Emergency Blanket and Bivy FAQs

If we have not addressed your question below, leave a comment and we will get you more information and an answer as soon as we can.

Q: Do emergency blankets really work?

A: Yes, emergency blankets are designed to retain up to 90% of your body heat by reflecting it back to you. Made from mylar, a polyester resin, they are also waterproof and windproof, offering additional protection against the elements.

A: While emergency blankets can be effective in retaining body heat, they are not a replacement for proper winter gear. They can serve as a valuable supplement in winter conditions to help prevent hypothermia, but they should not be relied upon as your primary source of warmth.

A: Emergency blankets are not breathable, so condensation can form inside, making you damp and potentially colder in the long run. They are also quite fragile and can easily tear, rendering them less effective. Additionally, they offer minimal protection against rough terrains when used as ground cover.

A: No, aluminum foil is not a good substitute for an emergency blanket. While both materials are reflective, aluminum foil is not designed to be durable or insulating in the way that mylar emergency blankets are. Emergency blankets are also more compact, making them easier to pack and carry.

A: Most emergency blankets are silver to maximize heat retention. However, some come in bright colors like orange or red on one side, which can be useful for signaling in emergency situations. The choice of color can depend on whether heat retention or visibility is your primary concern.

A: Emergency blankets are generally designed for single use. They are quite fragile and can easily tear or get punctured, especially if you’re moving around or if they get snagged on something sharp.

A: The terms “space blanket” and “emergency blanket” are often used interchangeably. Both are made from reflective mylar material designed to retain heat. The original “space blanket” was developed by NASA and has since been adapted for consumer use as emergency blankets. There may be minor variations in thickness or durability, but functionally they serve the same purpose.

A: Yes, it’s a good idea to include an emergency blanket in your first aid kit. They are lightweight, compact, and can be crucial for retaining body heat and signaling for help in emergency situations.

A: Yes, emergency bivy sacks are effective for retaining body heat and providing a barrier against wind and rain. Made from materials like mylar or polyethylene, they are designed to reflect back as much as 90% of your body heat, making them an excellent tool for emergency situations where warmth and protection are needed.

A: An emergency bivy can be used as a temporary substitute for a sleeping bag in survival situations, but it is not a replacement for a proper sleeping bag for planned outings. While bivy sacks can provide excellent heat retention, they usually lack the comfort and breathability of a regular sleeping bag. Using one for an extended period may lead to moisture buildup inside the sack, which could eventually make you cold.

Alex Derr, Founder of The Next Summit

Alex Derr is an Eagle Scout, climber, and environmental policy expert located in Denver, Colorado. He created The Next Summit to help others stay safe exploring the mountains and advocate to preserve the peaks for the future. Follow him on Linkedin or Twitter or click here to contact him.

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One Response

  1. Hi, nice article. One clarification could be to correct this statement: “2. The aluminum coating reflects up to 82% of your body heat back at you to keep you warm.” Warm objects loose heat in 3 ways, conductive, convective and radiation, the emerg blanket acts primarily on radiation heat loss while helping the other 2 but not at that high a rate. The study you are quoting correctly states 82% of the radiatative heat loss so a clarification in statement 2 would help. It does help conductive heat loss by trapping insulative air around the body and convective by protecting your warm air from the wind but those are likely well under the quoted rate. Radiative heat loss is also much lower than 1/3 of the total heat loss (all 3 types are not equal).

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