The Science of Survival: Wool Blankets

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By the author of The Prepper’s Guide to Post-Disaster Communications, and Zombie Choices

Hikers have long been familiar with the benefits of avoiding cotton clothing and material at all costs when it comes to maneuvering out in the backcountry. It’s because of this that many exclusively use wool socks and other synthetic materials for their clothing. But what about wool blankets?

Is there still room for wool when it comes to a survival situation? Let’s take a deep dive into the subject to see if wool blankets still have a place in the world of emergency preparedness.

wool blankets

Why wool blankets? 

As you likely already know, the chief problem with cotton is that once it gets wet, it loses 100% of its ability to keep you warm. In contrast, wool can still keep you warm even if it does get soaked. This in itself is a huge reason why so many people within the outdoor, search-and-rescue, and military world rely so heavily on these types of blankets.

For example, at least until 2010, it appears that the chief means by which the Norwegian military would keep casualties warm as they were being evacuated was with wool blankets. EMS responders in Norway used wool blankets combined with hot IV fluids until 2002, as well. They’ve largely resorted to “bubble wrap” since then, whatever the heck that means.

Why is it so important to keep casualties warm?

Because if you don’t, they end up with an increased risk of all kinds of problems.

wool blankets

Picture in your mind that you have found yourself dealing with the aftermath of a tornado. You crawl out of your devastated home to find that there is someone across the street that’s been extensively lacerated by glass shards that were blown through the air.

Tornadoes bring rain (sideways), so their denim jeans are soaked, and they are starting to shiver. They are in an austere environment, you have zero idea how long it will be until they can get proper medical care, and now they are growing hypothermic as well.

Studies have shown that hypothermia with trauma victims is associated with increased morbidity and mortality. One of the ways this plays out is with an increase in the probability that they will come down with some type of wound infection.

This is why researchers have studied the benefits of wool blankets for these cases.

The US Army has spent a bit of time studying this in the past.

In “Assessment of Hypothermia Blankets Using an Advanced Thermal Manikin” by K. Barazanji of the US Army Aeromedical Research Lab and JP Rugh of the National Renewable Energy Lab, it was found that placing a wool blanket between a casualty and the stretcher that they are on decreases their heat loss by 30%. If, in addition to this wool blanket, a reflective blanket is wrapped around them as well (on the outside of the wool blanket), then an additional 30% decrease in the loss of heat takes place.

Another study also found that using a wool blanket combined with a reflective blanket seems to be the magic combination for casualty evacuation.

Wool blankets with casualty evacuations save lives.

Even more interesting, I think, is the fact that this Barazanji study found that wool blankets worked better than electric blankets. That’s good news when you’re working in an austere environment (aka, virtually all disaster scenes).

(How do you survive a winter storm? Check out our free QUICKSTART Guide to find out.)

There are some factors about wool blankets you should know about.

Before you rush out and buy every wool blanket you can find, I will point out that I’ve personally found it incredibly difficult to find a wool blanket that hasn’t been inundated with fire-retardant chemicals.

This has always been something that concerned me. Your skin does absorb things through the environment around it, and having a chemical-laced blanket wrapped around me has never settled well with me. It seems that the research supports my gut feeling here as well. Are these chemicals safe for regular, daily contact with? Decide for yourself, but I say no.

I understand that virtually every item of clothing and blanket you use has chemicals in it that could be deemed harmful and that you can’t eliminate 100% of the risk from daily life, but I do try to be choosy about what I am willing to encounter.

Seeing a wool blanket that proudly advertises “Flame-resistant!” to me is a reason to go and shop elsewhere. Especially considering that wool is naturally flame resistant as it is, I don’t see the reason to act as if everybody with a wool blanket is juggling lit campfire logs or has a family history of spontaneous human combustion.

If you go out and shop for a wool blanket, I would keep all that in mind.

I did some warmth testing with some different blankets around the house.

To get some hard data on how different types of blankets retain body heat, I gathered a number of similar-sized blankets from around the house and used a ThermoPro TP50 thermometer to track the temperature underneath them. What I did was wrap myself completely in the blanket while sitting in a chair with the thermometer in my lap.

I recorded the ambient room temperature right before testing, sat for ten minutes wrapped in the blanket, and then immediately recorded the temperature underneath the blanket wrap.

Here is what I found:

Fleece Blanket

The fleece blanket was the typical “fluffy” blanket that looks like a Snuggy. A lot of people turn to these types of blankets because they’re cheap, they aren’t cotton (“Cotton kills”), and they’re comfortable.

The room temperature immediately preceding this test was 68.7 degrees Fahrenheit. After ten minutes under the blanket wrap, the thermometer read the temperature as being 72.5 degrees. The temperature was only raised 3.8 degrees Fahrenheit.

This was somewhat surprising to me as I thought that with all of the little air pockets that are inherently a part of fleece blankets, there would be a lot of trapped heat here. At least within the time span of ten minutes, that wasn’t the case.

My thoughts here are that perhaps fleece can trap extraordinary amounts of heat, provided it is part of a layering system. When I wear a fleece jacket, if it’s windy outside, the cold rips right through it. If I’m wearing something that blocks the wind as well, fleece jackets can quickly become almost too hot. Admittedly, there’s another variable there because there’s a second layering, but that’s what leads me to wonder if that’s how fleece blankets work.

“Mexican” Blanket

I’m not really sure of the proper term to call these, but they always look like a poncho, so the term seems fitting. These are typically a polyester blend, and you can typically find these at novelty beach stores for around $20. That’s where I got mine.

The ambient room temperature before the test was 68.2 degrees Fahrenheit. After ten minutes under the wrap, the thermometer read 72.9 degrees, making for a temperature difference of 4.7 degrees.

Wool Blanket

For this, I used an Arcturus Military Wool Blanket from Ready Made Resources. The room temperature here was 66.2 degrees Fahrenheit. After ten minutes wrapped in the wool blanket, the thermometer read 77.2 degrees Fahrenheit. The temperature was raised 11.0 degrees.

 

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Here’s what my experiment showed…

There really wasn’t even a contest between any of the other blankets compared to the wool blanket. Nobody other than the wool blanket reached double digits in the temperature, which, to me, is a very good inkling as to why search-and-rescue and other organizations regularly include wool blankets in part of their preparedness measures.

At the very least, with winter approaching, I would highly recommend you consider stashing away a few wool blankets in the trunk of your car. If you end up trapped on an interstate for hours on end in the dead of winter, this simple, inexpensive step could easily save a life.

As far as flame retardant chemicals go, I’ll also point out that the Arcturus blanket I used wasn’t sprayed with anything, meaning that being wrapped with the guts of a fire extinguisher wasn’t something that I had to worry about.

So whether you live in Tornado-Ville, Hurricane Land, or just somewhere where you regularly find yourself driving through heavy snow and ice, may I suggest considering the idea of picking up a wool blanket. Professionals throughout the world like them, sheep like them, and, for what it’s worth, I like them too.

But what are your thoughts? Do you have wool blankets as part of your survival kit? Or do you use something else? Let us know in the comments section.

About Aden

Aden Tate is a regular contributor to TheOrganicPrepper.com and TheFrugalite.com. Aden runs a micro-farm where he raises dairy goats, a pig, honeybees, meat chickens, laying chickens, tomatoes, mushrooms, and greens. Aden has four published books, What School Should Have Taught You, The Faithful Prepper An Arm and a Leg, The Prepper’s Guide to Post-Disaster Communications, and Zombie Choices. You can find his podcast The Last American on Preppers’ Broadcasting Network.

The Science of Survival: Wool Blankets
Aden Tate

Aden Tate

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  • I have one wool blanket I bought years ago at the Woolrich outlet. I have 8 wool blankets in my Amazon cart so we have one for every person who will be bugging in with me.

  • When I was in the Army 3 decades ago I loved the wool blankets that we used. While stationed in Germany I would always take mine to the field and use it in combination with my sleeping bag and stay toasty.

  • Great article. Wool has always been a good choice in blankets. Most rural or rurally raised people already know this. So the studies only confirm it.

    Today you will find a lot of wool blend, blankets. The Arcturus Military wool blanket is one of these, 80% wool, 20% synthetic fibers. But beware as there are many “military style” or other “wool” blankets that are only a 60/40 wool blend.

    I suspect that a truly 100% wool blanket might give slightly better results. But either way a 100% wool or a 80/20 wool blend is a great choice in a blanket.

  • I contacted the Faribault Woolen Mill (Faribault, MN) who told me they no longer treat their woolens. I have purchased from them before and can vouch for their high quality items. They have an online store, as well as their historic bricks and mortar (literally!) store.

  • Great and timely article!
    We have picked up many wool blankets over the last several years. 4 army type, 2 Swedish and 4 Pendleton’s. I can say all are warm but the Pendleton’s win hands down. They are heavy and 100% wool.
    Also like to layer winter clothes with SmartWool top and bottom base layer.
    Wool is one of the best materials for keeping a body warm!
    Wool hats, gloves and socks work too.

  • I have several I inherited & still use. Wool blankets & socks are things on my “GET” list. Anytime I find them at thrift shops, I buy them. I’ve even found several 100% wool shawls (of various sizes) & scarves. Wool socks can always be lined with thin socks so they don’t scratch.

  • I frequent estate sales and online estate auctions. I just recently purchased a box of blankets at an online estate auction. I went to the preview day to be sure of what I thought I saw online in the box. I was right, it was a Hudson Bay wool blanket. At the preview, I basically saw the label and my sister helped me do a quick once over. I didn’t inspect it thoroughly because I didn’t want to call too much attention to it but it seemed like a full, maybe even a queen, which made sense since most of the other bedding there was that size. I put it back in the large box of blankets and went home to watch it. I bid on it and ‘won’ it for $8! That’s for the box of blankets. All of them. Well, I spread that blanket out, and it’s a KING size! Happy camper I am. I LOVE this blanket, I’ve used it every night since I got it!

    I also found a wool blankets on FB MP for $20. When I got to the seller’s home, I asked if she had any others. She did, and I bought it as well.

    Most recently I bought a box of 4 blankets for $6 at another online estate sale. There were 2 wool army blankets in that box. They’ve since been washed and will be in my vehicles for the winter!
    For anyone else keeping a blanket in their vehicle, decide beforehand if you’ll part with it in an emergency. I once found an elderly dementia patient laying by the side of the road on a cold fall morning before dawn. I covered her with my blue wool blanket, and stayed until her family arrived and they gave me the blanket back. Had they not offered, I would have felt awkward asking.

  • Not to take anything away from what was written, but to provide a proven (to me at least) alternative. A U.S. Army poncho liner tied inside an issue mylar blanket, keeps you warm, dry, camouflaged, and helps to reduce heat signatures. Amazing the things you pick up in the infantry.

  • The woolen blankets with which I had experience, were tightly woven so that almost no wind could get through them. Knit woolen sweaters are not as tightly woven, so wind goes right through them. The same with heat. So if one is outside hoping that a woolen sweater will keep him warm, wear a windbreaker over the sweater.

    My experience with fleece is that it’s like knit wool, it needs a windbreaker. Another disadvantage of fleece is that it crushes under weight, thereby losing its insulating properties underneath a body.

    When I lived in cold country, I experienced temperatures down to -50°+ including wind chill. I wore long johns under cotton jeans (at those temperatures cotton didn’t get wet), a down jacket that was also a windbreaker that reached to my knees over a wool knit sweater, topped by a woolen scarf around my neck, with the hood of the jacket detached from the jacket but tied on my head so I could keep my head on the swivel while still warm, with my hands in bulky sheepskin mittens with the fleece inside that kept my hands toasty. I was outside for hours.

    Basically, what I say is that while wool is great, look at the strengths and weaknesses of each material and be ready to substitute if necessary.

  • This invaluable excerpt from the article can be enhanced in a minute:

    “In “Assessment of Hypothermia Blankets Using an Advanced Thermal Manikin” by K. Barazanji of the US Army Aeromedical Research Lab and JP Rugh of the National Renewable Energy Lab, it was found that placing a wool blanket between a casualty and the stretcher that they are on decreases their heat loss by 30%. If, in addition to this wool blanket, a reflective blanket is wrapped around them as well (on the outside of the wool blanket), then an additional 30% decrease in the loss of heat takes place.

    Another study also found that using a wool blanket combined with a reflective blanket seems to be the magic combination for casualty evacuation.”

    You’ve probably seen the many ads for emergency bags (I think made of reflective mylar) that reflect either 90% or 70% of a person’s bodily warmth. The 90% (more prevalent) have a bad outcome if your skin is immediately up against that bag because the bag collects your perspiration and make you wet at the worst possible time. The trick to eliminating that collected perspiration is to place some kind of fabric between you and that reflective bag. Given today’s discussion about wool blankets and the US army’s studies about the effectiveness of wool blankets underneath a reflective blanket … it would seem like a wool blanket inside a reflective mylar bag would keep you very warm AND DRY. In contrast, NONE of the ads I’ve seen over the years for those reflective bags mention anything about the need for at least some kind of fabric inside them to keep you dry so your perspiration doesn’t make you cold and wet — especially in freezing weather …which is a real killer.

    I bought my wool blanket a few years ago at an local army surplus store. The tag on it says nothing about being flame retardant. It also says it’s made of 85% wool and 15% mixed fibers. Finally it says “Made in India.”

    –Lewis

  • I purchased several 100% wool blankets from Amazon. Unfortunately, they were all “treated” — so…I had to take two of them at a time to the building’s laundry room and run them (with detergent) through FOUR or FIVE wash/rinse cycles, before I could place them in the dryer. Then they were acceptable for use. I keep two of them wrapped and in the truck for emergencies, and the other 8 stored for other emergency.
    Thanks for the great article.

      • Yes. There’s quite a bit of shrinkage with wool. It will come out “felted” which crafters love. The best bet is to wash in cold with woolite and air dry them. I’ve switched to 60/40 wool batt for quilting. Not too much shrinkage that way. Combined with cotton flannel makes a mighty toasty cozy keeping the scratchies away. We inherited quite a few old woolen blankets which none of the other family cared about. Lovely to have vintage!

  • I have several sleep systems that I use … one is using a Swiss army blanket (like the one you have a picture of) . While it is a good blanket , a more “lofted ” blanket is better . For instance a Hudson bay 4 point fur trade style blanket or a Mac Ausland (best) will keep you warmer.
    The system that I use for quick deployment is : a water-proof bivy sack (buck 703) , a cheap sun screen (for thermal break with the ground ) 2 @ inexpensive micro fiber throws ( cut and sewn to make bigger blanket) , a flannel cotton bag that I got from Montgomert Ward years ago that is good for warmer nights , a cot cover mosquito net that in summer keeps safe from the little blood-suckers , and in winter I use crumpled up as another thermal layer, and in reserve 2 mylar blankets and one mylar emergency sleeping bag. This set-up works well , although I have not had the occasion to try it below 20 degrees and this system is very light compared to wool blankets , but for long term I would probably take my wool too. I also have a wool serape’ ( mexican poncho as you call it) to use under a rain poncho for colder weather.

  • A few years ago I bought a hand made wool lined Oilskin poncho from blueangelical in the UK. This one piece of kit allows me to stay warm and dry even in the storms of the Sierra Nevada mountains. I’m confident I could sleep in a snowbank in that thing!

  • You are on the wrong track.
    FURS are the answer. PERIOD.
    I have been collecting furs and fur hides for years.
    You can find a fur coat on Craigslist in any US town for under $100.
    Humans ONLY SURVIVED because of FURS… Not wool blankets.
    Buy a FUR coat and laugh at winter.
    I am in Spokane, Washington.
    It is currently 27 degrees at 12 noon. It will drop into the teens tonight.
    I have a fur mattress cover that I sleep on, and a fur blanket.
    The heat in my house is set to 60 degrees.
    Good Luck All.
    Gunny
    Spokane, USA

  • The two queen size Kenwood wool blankets (I’m in Canada) we received as precious wedding gifts in 1969 are in perfect shape, and have been stored away ever since we moved on to down duvets. Until reading your article I had decided we should keep them to use as ‘curtains’ over windows in the event of an extended power/heating outage, as a lot of heat is lost through windows, especially if they are uncovered or covered only with blinds. I will now make sure to add a space blanket and at least one wool blanket to the winter emergency kit in my car. Thanks for sharing!

  • I always go natural when I can. Wool socks, wool blankets, brick house, stone walls, wood floors, real wood veneers, marble, granite, etc. They are not only beautiful but resist weather better. Not surprised wool is the best.

    Cotton t-shirts from 30-40 years ago is fine also but maybe for hot weather. They don’t smell at all when sweating but still smell cottony (no body odor) amazing, but I find the new cotton t-shirts do smell. Very strange.

    I also found out those that resist stains (cotton kind) make you sweat like hell even though it is normal ounce t-shirts. I figured the teflon is some kind of plastic coating on the threads. To me, NOT good.

  • Wool .! Rocks.., that said I bought an old looking wool blanket at a thrift store. Turns out to be one of the best made. Northern wool ware by LeeBeckman company, so we looked it up on ebay lol SCORE = $200 and I paid 5
    YES …!!! Wool Keeps You WARM 🥵 YAAAH

  • Really thick and warm wool blankets can be found on Ebay, look for vintage wool blanket. Double or triple the thickness of modern wool blankets.

    The only problem with bubble wrap is that it can be punctured, and will not last for decades. Other than that, it is incredible. My office building was built in 1790, and does not have insulation. And heavy ice cold plaster sucks up every bit of warmth in the room. I put a layer of bubble wrap on the walls, and covered it with decorative rugs, although a quilt or other heavy fabric would do too. Warm! And toasty! Given current oil prices, I’ll be doing this at home too. Bubble wrap is fantastic as insulation, or they would not have switched to it.

    Biggest problem I see with it as a body wrap is that since it is plastic, it will not absorb sweat, which can lead to nasty re-chilling problems once a person warms up enough to sweat. A blanket underneath the bubble wrap would fix that.

  • Been a firm believer in wool for decades. A lot of our “camping” clothing is wool. Merino, worsted and cashmere mainly.
    Aden, “Bubble Wrap is a type Casualty blanket that heated air is forced through the channels to aid in keeping the victim warm. Now the heat unit is battery operated.
    I hand wash woolen items in Borax to increase its fire retardant capabilities as it’s 100% natural.

  • Woohoo wool! Love my handspun handwoven Shetland wool blankets. Keeps me toasty warm at night even on the coldest nights. My sheep provide lightweight crimpy fine wool, perfect for any hand knit garments like sweaters, hats, scarves, mittens, socks and woven blankets and fabric for clothes. Not enough time in the day to explore all the wooly goodness, though I probably should make ‘sacrifice’ blankets to keep in the vehicles.

  • Thanks for the article. I fell in love with wool about 15 years ago. I was a n Ankara, Turkey and the apartment I stayed in was colder than any time I had lived in Alaska! I took my ankle length wool coat and laid on the wool side-not the liner) and then wrapped it around me and pulled the hood on. In about 8 minutes, I started to warm up and finally fell asleep.
    Now, I work with wool. As a prepper, I buy the raw wool, wash it, and mostly card it and felt it. You can cut the felt pieces to make clothing or just leave it as a blanket. Really glad to read this.

  • If you wash your wool blankets and then dry them in a dryer, be sure to clean out dryer vent tube afterwards. Some of the less expensive wool blankets that I bought specifically for carrying in the vehicles shed fibers so severely during drying that fibers completely clogged the dryer vent tube. It’s a matter of taking the tube apart and cleaning it out – something you should do once a year anyway. But I was surprised at the sheer volume of fibers. So, check your dryer vents after washing wool, not just the pull-out filter. Just FYI.

    • i was told never to wash the wool blankets and to only have them dry cleaned plus i only have the 1 wool blanket its an aabe 1963 and its really heavey and i would not want to destroy it for any reason

  • I’m surprised most ppl are looking/sourcing actual wool “blankets”. What about going to fabric stores and buying wool coating? Shelton, Melton, novelty woven, flannel, knit, jacquard, etc – as long as it is coating weight, and a good price (sales), buy it. I have several wool blankets that I wash regularly. All are pieced together from wool remnants – I have a few color schemes, and either add on or set aside to add on as needed.

    I machine wash my wool regularly (1x a week at least), cold water, normal agitation, and then dry on hot (I like the removal of pet hairs and misc lint). It doesn’t shrink as much as one would expect – for my queen sized blankets, maybe I add on .5/yd, 1 yd a year or so – if that. Plus, it fells/felts with each wash, gets softer, thicker, it repels water (or senior pet accidents), and serves not just in winter, but isn’t bad for 3 season bedding – outside of super hot mid-summer weather. I do wash it alone – without the added agitation of sneakers or towels or blue jeans (which could/would ‘up’ the shrinkage in the machine). You could handwash/or wash delicate, hang dry, but know, you can also wash with a “meh” attitude and your blanket will turn out just fine. It will turn out warmer too!

    I haven’t tried making blankets with wool dress or shirt or pants-weight fabric, but the general rule, FYI, is that the looser the weave, the looser the strand, the more it will shrink – Wool coating is a tight weave to begin with (esp shelton/melton), so there’s only so much wiggle room.

    Anyway, people. Fabric stores. I’ve seen undyed, untreated wool as low as $3/yd. This yr – wool coating I’ve seen between $6 yd to 20/yd depending upon the weave, color, weight and width and if its mixed w/a finer natural fiber (cashmere, camelhair, angora, etc – more $$). Plan for anywhere between 3 to 10 yards. 6 yards is good enough for 2 yrs worth of regular washing w/ pieces still left over to add on. Overall, darker shades (conservative colors/pleasing colors) will set you back more than the louder colors – but its all warm.

  • i was given an aabe 1963 wool blanket years ago by a freind and love it and some how i all ways seem to know for a fact were it is located…i was living in southern texas in a house that had no central heat i just used little electric space heaters and my henry 5k classic amp to heat the place those 2 3cx 1200 a7s pumped out some serious heat but i qiuckly learned it was cheaper to heat the bed than an entire room….

  • Aden Tate,
    using wool to sleep in and keep warm is like dressing in layers to go outside in cold weather. wool by itself won’t do it. cotton sheets, a good wool blanket and a down comforter on top will keep you toasty warm.
    you mentioned bubble wrap. its something i have never considered, after all it’s all about loft, it’s also a vapor barrier like mylar.

  • When I was in high school our band uniforms were wool (Michigan, USA). My director said it’s both the warmest amd coolest fabric, therefore most economical.

  • I wholeheartedly agree with you about the value of the wool blanket. I have one and plan on getting a few more – as budget permits. However, I would like to point out to you Wiggy’s sleeping bags. I have owned one for two years and every winter this is what I sleep in. We keep the house at 57 F to save electricity costs and I am so incredibly cozy in my sleeping bag – all night long. He makes his bags out of something called ‘lamilite’. Truly incredible stuff. One video was of a guy testing out the claims by Wiggy by drenching his sleeping bag in water, sleeping naked in 0 degree weather and climbing in the bag even though it was wet. He woke up warm and dry in the morning. These bags are truly amazing. Couple that with a woolly blanket and life’s a joy.

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