Mylar blanket: a reflector, not a sleeping bag
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Quick answer
A mylar or space blanket is a thin metallized sheet that reflects your radiated body heat back toward you and blocks wind and rain. SOL says its emergency blankets reflect 90% of radiated body heat. They work best wrapped close, combined with dry insulation and shelter, because they do little against heat lost to cold ground. CDC notes hypothermia can happen even above 40°F when someone is chilled by rain, sweat or cold water.
What a mylar blanket is
- The name: "mylar" is a trade name for polyester film, and people use it for any shiny emergency blanket.
- What SOL uses: SOL describes its blanket as vacuum-metalized polyethylene and says it will not shred like traditional mylar blankets if nicked or punctured.
- Waterproof and windproof: SOL lists its Heatsheets material as both.
- Visibility: SOL's orange outer side is meant to help rescuers see you.
Do mylar blankets work?
- Radiated heat: SOL says its blankets reflect 90% of radiated body heat; its Sport Utility Blanket lists up to 80%.
- Wind and wet: blocking wind and rain matters because CDC says hypothermia can occur above 40°F if a person becomes chilled from rain, sweat or submersion.
- The ground: a thin sheet does little to stop cold soaking up from the ground; sit or lie on a pack, foam pad or branches as well.
- Close fit: wrap it around you, under a jacket layer if possible, rather than leaving a big air gap.
Blanket, XL blanket or bivvy
| Option | What SOL lists | Best use |
|---|---|---|
| Emergency Blanket | 90% heat reflective, waterproof, quiet, orange | Every car, bag and first aid kit |
| Emergency Blanket XL | Fits two people, survival tips printed on it | Families and shared shelter |
| Emergency Bivvy XL | Shelters two people, sealed seams, tinder cord drawstring, rescue whistle | Overnight emergency shelter |
A bivvy is a sleeping-bag shaped sack that closes around you instead of lying loose; see our bug out bag list for the single SOL bivvy.
How to use one in an emergency
- Get out of the wind and wet first, into a car, building or behind shelter if you can.
- Insulate from the ground with a pack, pad or dry branches.
- Wrap the blanket around your body, including the head and neck, which CDC says to cover when rewarming.
- Add dry layers: CDC advises removing wet clothing and warming under loose, dry layers.
- Signal: show the bright side to rescuers.
A blanket can also serve as a ground cloth, gear cover or first aid blanket, SOL says.
More than a blanket: other uses
- Shelter and tarp: SOL says its Heavy Duty Emergency Blanket can serve as a survival shelter, tent ground tarp, gear cover or load hauler.
- Rigging: SOL's Sport Utility Blanket adds reinforced grommets for rigging a shelter, a shoulder clasp for hands-free use and a stuff sack with a whistle and tinder cord drawstring.
- First aid: SOL lists first aid blanket use for the XL; keep one in the first aid bag so it is with the person who needs it.
- Where to stash them: one per person in the car, the go-bag and the home kit; they fold small, so there is little reason to share.
Hypothermia signs to watch for
- Adults: shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech and drowsiness, per CDC.
- Babies: bright red, cold skin and very low energy.
- Who is at risk: CDC lists older adults with inadequate food, clothing or heating, babies in cold bedrooms, people outdoors for long periods and people who drink alcohol.
- Medical emergency: CDC says a body temperature below 95°F needs medical attention immediately; warm drinks can help but never alcohol, and nothing by mouth for an unconscious person.
An emergency blanket supports these steps; it does not replace medical care.
What to look for when you buy
For every kit: SOL Emergency Blanket
Best for: Cars, go-bags and first aid kits
SOL lists 90% heat reflection, vacuum-metalized polyethylene that resists rips and will not shred if nicked, waterproof material, quiet in wind and high-visibility orange.
Watch out: Amazon sells it in multi-packs; one sheet does not insulate you from cold ground.
See options on Amazon (opens Amazon in a new tab)For two people: SOL Emergency Blanket XL
Best for: Couples, parents with a child and shared shelter
SOL lists a two-person size, 90% radiated heat reflection, waterproof and windproof Heatsheets material and survival tips printed on the blanket.
Watch out: Larger to unfold in wind; practice once at home.
See options on Amazon (opens Amazon in a new tab)Overnight shelter: SOL Emergency Bivvy XL with Rescue Whistle
Best for: A sleeping-bag shaped shelter for two in an emergency
SOL lists room for two, waterproof and windproof material reflecting 90% of body heat, sealed seams, a tinder cord drawstring and a rescue whistle.
Watch out: Condensation can build inside sealed material; vent when you can.
See options on Amazon (opens Amazon in a new tab)Questions people ask
- What is a mylar blanket?
- A thin metallized emergency sheet that reflects body heat; SOL's version is vacuum-metalized polyethylene that reflects 90% of radiated heat.
- Do mylar blankets work?
- They reflect radiated heat and block wind and rain; add ground insulation and dry layers for real warmth.
- How do you use an emergency blanket?
- Get out of wind and wet, insulate from the ground, and wrap it close around your body, including head and neck.
- Can a mylar blanket treat hypothermia?
- It helps keep heat in, but CDC says a temperature below 95°F needs medical attention immediately.
Sources
- Emergency Blanket, SOL (Survive Outdoors Longer)
- Emergency Blanket XL, SOL (Survive Outdoors Longer)
- Emergency Bivvy XL with Rescue Whistle, SOL (Survive Outdoors Longer)
- Sport Utility Blanket, SOL (Survive Outdoors Longer)
- Preventing Hypothermia, Centers for Disease Control and Prevention
- Heavy Duty Emergency Blanket, SOL (Survive Outdoors Longer)