You’ve seen space blankets before. Those wonders of DuPont and NASA ingenuity are made from incredibly thin Mylar, but they look like aluminum foil at first glance. So what’s the big difference? Aren’t they just basically the same thing? Unfortunately, no, they’re not the same. However, there are some ingenious ways you can use aluminum to help keep you warm in the winter. Even though it makes a poor blanket, shiny foil is excellent at helping keep out heat when appropriately used. I’ll help you learn some of the uses for foil and explain why you need Mylar blankets for emergency warmth outdoors.
Shiny Foil Blankets Won’t Keep You Warm
You may have seen food wrapped in shiny foil to keep it warm, but if you’re paying attention, it doesn’t help for very long. Sadly, though foil has outstanding reflective qualities, the closer you wrap something in it, the less it helps keep heat in. Foil is a lousy heat insulator.
Although it makes an okay substitute for a Faraday cage in a pinch, keeping out electromagnetic signals is hardly the same thing as keeping heat inside. Realistically, any wrapping will help hold heat in for a few minutes or a couple of hours. Foil, however, is better at reflecting than insulating against heat loss.
To better understand foil, you only need to look at cooking. Despite all the legends that spring up, the science doesn’t support any of that mythos. Shared knowledge and common sense aren’t always the same thing.
Shiny Side Vs. Dull Side of Aluminum Foil
Anyone who cooks has heard the age-old debate about the shiny Vs. the dull side of the foil. You probably know someone who insists that one side is nonstick. Allow me to help clarify the issue with a little help from and some basic science.
First, there is such a thing as a nonstick foil. However, you have to buy it specifically. In that case, the dull side is labeled, so you know it’s the nonstick surface.
Otherwise, there’s no unique quality that keeps food or anything else from sticking to the foil. Regular aluminum foil is not treated with a nonstick substance on either side. The shine of the metal doesn’t affect this even a little bit.
Shiny Side of Foil in Cooking and Warming
As for ordinary foil and the shine on one side, this happens during the milling process. One side of the foil is in contact with another metal surface during creation. This is the dull side. Meanwhile, the half that’s not touching anything stays shinier.
To be perfectly clear, there is no right side of the regular foil to use. According to Readers Digest and Reynolds Wrap, the side of the foil you use does not affect cooking. Shiny side out or in, it does not significantly impact the cooking time, temperature, or how the food bakes.
Additionally, shine doesn’t insulate cooked food any better after you finish cooking. The same goes for your body. You are made of meat (muscle tissue), fat, bone, and all the same ‘ingredients’ as any animal.
When you cook with foil, it only affects one part of cooking. A foil cover keeps in natural moisture. Hence you can avoid making something too crispy or brown on top while you’re still heating the inside. That’s all it does.
Shiny Aluminum Foil Keeps Some Heat Out
While foil makes a loud and mostly useless jacket material, there is a heat-related use for the inexpensive aluminum sheeting that can help prevent heat transfer. Apply it to your windows in the summertime. The minuscule insulating quality won’t help, but the light and heat reflection will.
Make no mistake; aluminum foil is no match for dual-paned gas-filled windows. However, in a pinch, you can use it to help keep the temperature stable indoors during the warmer months. You’ll need foil and double-sided tape for this trick.
Place a layer of heavy-duty aluminum foil on the inside of the window, and add a layer of bubble wrap over it. The combination of the air trapped inside the pockets and the foil resisting the heat will help keep your home cooler in the summertime.
Similarly, in winter, you can swap out that foil for large bubble wrap to help hold in the heat. That’s a subject for a different article. The moral of the story is that foil isn’t good at keeping heat inside of anything, but it will reflect outside temperature away.
A Deadly Mistake
Using foil to try to warm yourself in winter might be the last mistake you ever make. Shiny aluminum foil can help hold a pocket of air in place, retaining moisture and temperature. However, the effect won’t last forever.
If you think foil holds heat well, you only need to take a foil cover off something that’s was in the oven a minute ago. Unless you touch the pan or release hot steam on yourself, you probably won’t feel the heat. Trapping a pocket of air is an efficient way to maintain a constant temperature, but use a better insulator.
A camo print pack of Titan Two-Sided Emergency Mylar Survival Blankets from Amazon will keep a whole family warm. Skip the extra weight, and lack of insulation foil gives and do the job right instead. Plus, a good Mylar blanket is compact and takes up about as much space as a few folded tissues. You can have them delivered when you order here.
Mylar is Not Shiny Aluminum Foil
It’s an easy mistake to think that shiny aluminum foil and Mylar are the same things, but the difference is night and day. Sure, they look alike because both are silver and reflective. Both also make a lot of noise when crinkled or moved. That’s where the similarity ends.
Developed by NASA in 1964, Mylar blankets used an existing technology from DuPont to create a less-than-thirty micron thick film that helps you retain up to ninety percent of your body heat.
Also known as BoPET (Biaxially-oriented polyethylene terephthalate) or polyester film, the tensile strength of Mylar and heat-retaining qualities were initially used for something different. Mylar isn’t gas permeable. Hence it’s used in food packaging to this day. Whenever you open a yogurt cup or another shiny sealed container, that’s not aluminum foil keeping out mold spores and oxygen.
Though you should never seal yourself in like food, as long as it has a breathing hole, Mylar makes a great human-cover as well. Try a Tact Bivvy 2.0 Emergency Sleeping Bag for cold camping. Don’t let the name fool you, ‘reflective polyester film is the same as Mylar. The only difference is that “Mylar” is a trademarked brand name like “Q-tip.” You’ll love how warm and dry it keeps you by any name. Check the reviews here on Amazon.
Shiny Foil Won’t Warm You But…
For urban survivalists, skip the shiny foil, there’s a much better solution to help keep you warm. You may not know this, but homeless people hit on a grand urban solution for heat insulation long ago. Balled up pieces of paper will help hold in the heat.
In the coldest parts of winter, it’s not uncommon to find street people in cities like New York and Chicago dropping little balls of newspaper or junk mail. For the same reason, homeless people traditionally sleep inside cardboard boxes. It keeps them off the cold ground and holds a layer of warm air around them at night.
As strange as it seems, the paper is an exceptional insulator. Those little papery cardboard wraps on your to-go coffee are there for a good reason. Convection, conduction, and radiation are all problems in colder temperatures, and the solution to all of them is the same. You can even get recycled paper home insulation, though it’s been treated to prevent mold, mildew, and pests.
Polyester Film is Still the Best
Of all the inexpensive heat holding solutions, shiny aluminum foil is dreck, and paper is alright. Still, Mylar is the best solution out there right now. Instead of wasting your time on aluminum, get a high-quality Mylar solution instead.
For outdoor treks, I suggest grabbing a Prepared 4X Emergency Poncho from Amazon. In addition to keeping you warm while you sleep, it’s a superb, lightweight, and durable solution on the go. These twenty-four micron thick Mylar ponchos fit in your pocket or cover your whole body. Plus, your hands are available for other activities. Learn more by clicking here.
Shiny aluminum foil is the fool’s gold of emergency survival heat solutions. It looks good, but it’s not what you were hoping for when you noticed it. There are many superior solutions out there.
For better information on emergency survival blankets, check out the superb video above by Far North Bushcraft and Survival. Lonnie debunks some of the misconceptions about survival blankets and shows you how to survive the cold realistically.
You’re not a baked potato, so please don’t wrap yourself in foil. Get a Mylar emergency blanket instead.