Outforia Quicktake: Key Takeaways
- Hand warmers generate heat through chemical reactions, with disposable and reusable options available.
- The body prioritizes maintaining blood flow to the core in cold temperatures, leading to cold hands and feet.
- Disposable hand warmers produce heat through the oxidation of iron powder, providing up to 12 hours of warmth.
- Appropriate clothing and layering help keep the body warm, and clothing designed with disposable warmer packs provide extra heating.
- Reusable warmers come in various forms, including gel, battery-operated, and catalytic warmers, each with its unique benefits.
Hand warmers can be a terrific way to stay warm when you’re having a good time outdoors. They generate heat through chemical reactions and come in a variety of disposable and reusable options. No demon fire involved. But not all hand warmers are equal.
So, how do hand warmers work exactly? And how important are they? Let’s find out below!
Why are Hand Warmers Important?
No one likes to be cold when we’re having a good time playing in the snow. We want to keep snowshoeing, snowmobiling, skiing, ice fishing, or winter hiking without worrying about having cold fingers.
But there’s a very good reason why our fingers and toes get cold before the rest of us. To keep your vital organs warm, your body ensures that blood flow to your core is maintained when it’s cold outside. Your hands and feet may start to feel chilly due to the altered blood flow to those areas.
The easiest way to keep our digits warm is, of course, with good-quality gloves, mitts, and socks. Wool is best for this.
But there’s an easy way to provide our hands with an extra jolt of warmth that can last up to twelve hours. Hand warmers. These can be a great addition to your winter gear, especially if you are planning on spending extended periods of time outdoors.
When enjoying the chilly outdoors, it’s important to keep an eye out for any signs of frostbite, such as numbness or discoloration of the skin.
According to John Hopkins Medicine, frostbite is an injury that can happen in extreme cold. Unprotected body tissues freeze, and if the affected area is not treated right away, permanent damage may result.
Frostbite is more likely to occur in people who are exposed to cold temperatures for prolonged periods, have poor circulation, or are not properly dressed for the weather. To prevent frostbite, dress warmly and limit time spent in extremely cold conditions.
How Do Handwarmers Work?
The first patent for a hand warmer as we would recognize it today was issued to Jonathan T. Ellis of New Jersey in 1891. Ellis’ hand warmer was designed to be filled with hot water and placed in a pocket or muff to keep hands warm in cold weather.
The first commercially produced hand warmer was created by Japanese inventor Niichi Matoba, who used an oxidation reaction that produced heat using platinum catalysis.
Matoba’s invention was initially designed for use in the Japanese military during World War II, but it became popular among civilians and inspired the development of other types of hand warmers.
Today, hand warmers are available in various forms, including chemical heat packs and rechargeable electric models.
Disposable Hand Warmers
How do they work? In disposable units, iron powder reacts with activated carbon, vermiculite, and salt to produce heat as it oxidizes. Yes, oxidation is also known as rust.
The heat is then released slowly over several hours, providing warmth for your hands, feet, chest, or back.
The chemical reaction causes the hand warmers to commonly maintain a temperature of around 100–110°F, but they can reach 135°F.
- To use a disposable hand warmer, open the package, shake it for about fifteen seconds to get the chemical reaction going, and place it inside your gloves or pockets to keep your hands or feet warm for up to twelve hours.
To extend the life of a hand warmer, simply put it in a zippered plastic bag, and squeeze the air out before sealing.
The iron powder in the little warmer pouch needs oxygen for the chemical reaction that causes the heat.
- When you seal the pouch in a plastic bag, you deprive it of oxygen. So the chemical reaction is halted until more oxygen is reintroduced. This is an environmentally responsible way to reuse the warmer pouch if you’ve only been outside for a few hours.
Warmer packs are a great idea, and outdoor adventure clothing manufacturers are embracing the concept.
Wearing Appropriate Clothing
In many modern gloves, socks, winter coats, and even hats, designers are including zippered pockets that are just the right size for disposable warmer packs.
This isn’t just convenient for you; it also keeps the pack away from your skin. You still have steady warmth without any danger of accidental burns. Perfect!
I’ve mentioned before that the chemical reaction that produces the heat needs oxygen. So, if you wear tight clothing, you deprive the warmer pack of one of the required components. Essentially, depriving you of much-needed heat.
As any of us who have spent a significant amount of time outdoors knows, one secret to staying warm is layering. This means wearing a base layer that will keep perspiration away from your skin. Being cold and damp can lead to hypothermia!
So, choose moisture-wicking clothing for your base layer. This is the only layer you want to be snug, so the material can shift the sweat away from your body. Moisture-wicking long underwear can be found at many outdoor supply outfitters.
Follow that with a long-sleeved sweater, sweatshirt, or fleece jacket, then your outer coat or jacket that will protect you from the wind or blowing snow. Preferably with a handy disposable warmer pack, either adhered to the inside or tucked into your inside pocket.
The air inside your coat will provide oxygen for the chemical reaction.
Folks who are cold intolerant for medical reasons, but who still want to enjoy the great outdoors have found that clothing designed for extra heat sources fits their needs. Reynaud’s Syndrome, for example, is a painful vascular condition.
In response to cold or stress, small arteries in the hands, feet, nose or lips narrow, causing extremities to appear white.
When blood flow normalizes, the affected body parts can tingle or even be painful. Portable warmers can help manage this condition.
For those of us not hampered by such medical conditions, disposable warming packs come in all sizes, from palm-sized to nearly the size of a paperback book.
You can get them in a variety of shapes as well, including insoles to fit into your winter boots or rectangular patches to sit on your chest between clothing layers. Remember, never put hand warmers directly on your skin!
On average, toe warmers will generate about seven hours of warmth, and hand warmers and larger patches will stay warm for approximately ten to twelve hours.
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Reusable Warmers
Gel Warmers
One type of hand warmer doesn’t contain iron like the disposable ones do but uses a gel that releases heat as it crystallizes. It sounds mind-boggling, I know but bear with me while I try to explain.
Reusable gel-based warmers contain a liquid that has been cooled to just below its freezing point, a small ferrous metallic disc, and sodium acetate crystals.
Sodium acetate is used for a lot more things than you might imagine, including sealing concrete, and replacing vinegar on “salt & vinegar” potato chips!
When the metal disc is squeezed or snapped, it releases sodium acetate particles and a chemical reaction occurs that converts the crystals suspended inside the gel into what seems like ice. Surprisingly, during that conversion from a liquid to a solid, heat is generated.
The benefit of these warming packs is that the heat is created quickly and is initially much hotter than disposable hand warmers.
Unlike single-use warmers, these gel packs can be reused by submerging them in boiling water for a specific amount of time to convert the solid mass inside the pack to a liquid.
But this restoration process is also a drawback, because of the energy needed to return the pack to its previous state. However, they do come in a variety of sizes for varied uses.
Check out this video showing how to activate and reheat a gel hand warmer.
Battery Operated Warmers
This type of hand warmer uses rechargeable lithium-ion batteries to generate heat and can be turned on and off.
While they are a little more pricey than their gel-pack peers, they do pay for themselves over time if you spend a lot of time outdoors. These warmers can be recharged by plugging them into a wall or a USB port.
My sister-in-law, Susan, lives with Reynaud’s Syndrome and it leaves her feeling cold almost all the time in the winter. She agreed to sit down with me and answer my questions about how she still enjoyed outdoor winter activities with such a painful circulatory issue.
Susan has had Reynaud’s for about five years, and learned the hard way that without a source of warmth on cold days, her hands begin to feel cold, her fingers “pulse”, become painful, and turn what she described as “dead fish white”.
Within just 5 minutes of exposure to cold. When warmth returns to her hands and the blood vessels open up again, normal blood flow returns. This causes a painful burning sensation in her fingers.
She was quite certain that the two winter activities she enjoyed most, ice fishing and snowmobiling, would not have been possible without heated gloves.
I asked her for more details on the gloves, and she was happy to not only share her experience with them but also let me take pictures and try them out for myself.
Her heated and rechargeable gloves were rather expensive when she bought them 5 years ago at an outdoor store. They cost a little over $250.00 CDN then. But she was convinced they would be a good investment.
She charges them overnight and they provide 3 levels of heat all day. The battery pack sits atop the back of the wrist with a control button nearby.
This button glows with a different color, depending on the setting, allowing the user to know what setting the gloves have been set to. Green signifies low, blue signifies medium heat and red indicates a high heat setting.
With the gloves on my own hands, I was surprised at how quickly the gloves warmed the ends of my fingers and my palms. Within 2 minutes, it was easy to feel the heat along the length of my fingers.
Susan told me she starts her gloves on high for about a minute before she puts them on, and then turns them down to the medium setting.
Although she’s never timed exactly how long her gloves generate heat before the battery loses its charge, she told me that even when she works a 10 hr day, her gloves have never failed to keep her hands warm.
She works as a delivery courier and is adamant that without her heated gloves, she would suffer even more pain in her hands and fingers.
Catalytic Warmers
This style of warmer uses lighter fuel, which is held in a fibrous mat within the body of the warmer.
A catalytic burner unit is placed atop the mat and wicks the fuel up and into the burner. This filling process can take a couple of minutes to complete properly.
Using the temporary flame from a lighter or matches, combustion within the burner unit produces flame-free heat. Then you slide the protective casing over the whole thing and place it wherever you need it.
These warmers also come in a variety of sizes, none of them small enough to fit inside a glove or sock comfortably, but there are models that fit well inside most coat pockets.
One drawback is that there is no way to stop the combustion once it starts. The heat produced can be quite hot, and for this reason, a cloth pouch is included at purchase, and its use is encouraged.
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Can Warmer Packs Be Used For Other Purposes?
Hand warmers can be used for purposes other than warding off frostbite;
- Disposable warming packs can be activated in the morning and tossed into a lunch box or bag to keep the food warm until you’re ready to eat. Admittedly, this works best if you’re able to open the lunch box or cooler every now and then to replenish the oxygen inside.
- Warmers placed in the bottom of your sleeping bag will ensure your bedding will be nice and toasty at bedtime.
- Hand warmers placed in your hiking shoes or snow boots overnight will eliminate any dampness from perspiration or accidental slips into puddles.
- If you work or study in a cold building, warmers packs under your desk can help keep your feet and legs warm, helping you focus.
- Wet socks can be dried overnight by slipping a hand warmer into each sock.
- Disposable hand warmers can produce enough gentle heat over a number of hours to prevent tender seedlings in a small greenhouse from being harmed by an unexpected frost.
- Wrapped in cloth such as an extra pair of socks, hand warmers can also be used to protect electronics such as smartphones, GPS units, and cameras from damage by cold temperatures.
- Disposable hand warmers can also be used to keep pipes from freezing. Many plumbers recommend taping an activated warming pack to a cold-vulnerable section of pipe to keep the pipe warm during a cold snap.
- At the end of a long day of hiking, snowshoeing, or skiing, a warming pack can relieve the cramping of over-worked muscles.
You may also like: Hiking in Snow: How To Keep Hiking When The Weather Gets Cold
Hand Warmer FAQs
How do I activate a disposable warmer?
Disposable hand warmers are activated by opening the package and shaking for about fifteen seconds in order to initiate the chemical reaction.
How long will a warmer pack last?
-Rechargeable warmers can last from 6 to 14 hours, depending on the model.
-Catalytic-type warmers can last 6 to 21 hours, depending on the manufacturer and heat setting.
-Disposable warmers can last from 7 to 12 hours, depending on the design and manufacturer.
-Gel pack reusable warmers can last from 30 minutes to 45.
Do unopened disposable warmers expire?
The duration of a warmer pack depends on the type and brand of the product, as well as the environmental conditions in which it is used.
Unopened warmers typically have a shelf life of several years, but it is recommended to check the expiration date before use.
How should I deal with a used disposable hand warmer?
While the outer packaging of a disposable warmer pack is not recyclable, you can cut the pouch open and compost the components inside.
Iron powder, salt, and vermiculite are natural minerals, which makes them perfectly safe to compost. Just remember to toss the packaging away responsibly.
Iron powder is a great source of iron for plants, and salt can help control weeds in your garden. Vermiculite, on the other hand, helps improve soil aeration and water retention.
Are hand warmer packs toxic?
Iron, salt, and charcoal are all natural materials and are not toxic. Disposable hand warmers can be cut open and the contents composted or scattered outside since they are all natural contents.
The pouch that comprises the outer part of the hand warmer is not compostable or recyclable and must be disposed of responsibly in the trash.
Hand warmers come in a wide enough variety of sizes, chemical compositions, and cost to suit everyone.
