Toasty Toes: Winter Boot Insulation

Key Points

  • Insulation in a winter boot is vital to keeping feet warm and comfortable in cold temperatures.

  • Many wrong terms refer to boot materials but do not indicate insulation.

  • Insulation in boots is measured in grams; the heavier the insulation, the warmer the boot.

Have you ever bought a pair of boots based on style and fit only to find that your feet froze in them later? Getting stylish boots is one thing, but getting functional boots takes more research. There are so many varieties on the market that it's hard to decide what you want and need before you purchase.

Brothers Mike and Bill Brooks, creators of Rocky Boots, say, "The level of protection varies depending on the measurement of the insulation." If you want to understand insulation, it helps you to make the right choices the next time you are in the market for winter boots.

The Importance of Insulation

Cold feet are uncomfortable, can impact your overall health, and what you can do outside when the temperatures drop.

Insulation in your boots preserves warmth so your entire body has a better chance of standing up against cold weather. Underestimating the weather has severe and painful results. At the same time, wearing boots with too much insulation can chafe, cause sweat, and make you even more uncomfortable.

The Right Terms

While some tricky terminology surrounds insulation, you also want to look for certain terms when you check the details on any boots you consider. Here are some of the insulation terms to know.

Thinsulate Insulates Nicely

Thinsulate is one of the most popular terms relating to boot insulation.

Boots in the snow

You get excellent insulation in your boots in a small way. Thinsulate is what it sounds like — insulation on the thin side. It is also known for being durable, so it will not break down when it gets wet or because it gets used a lot. Since it is not bulky, it is more comfortable for daily wear. The microfibers in the boot trap air and prevent colder air outside from getting into the boot. You might see Thinsulate on boots, jackets, gloves, hats, and other winter wear. The weight of the material ranges from 100 to 1000 grams of insulation.

Remember that the larger the number you see, the warmer the boots should be. Other synthetic materials work similarly to Thinsulate, but Thinsulate is the most widespread and popular option.

Shearling Insulation Feels Great

Shearling, or fleece, insulation is soft and warm and works best with bare feet.

It is one of the warmest types of insulation and feels good against your feet, but it has durability problems. It can break down over time and become less warm and comfortable. This type of insulation is suitable for general use but not work, outdoor adventures, or other heavy wear. It is popular and effective if you understand the limitations and need a light-wear boot.

Primaloft Keeps Feet Dry

The U.S. Army created this brand of synthetic insulation, but it can protect any boot wearer against the elements.

Primaloft is water-resistant and can keep feet dry inside boots, even in downpours. The material is also lightweight, which makes the boots easier to store — especially if you have several pairs. It also repels water, so there is no discomfort with wet feet inside a boot. Primaloft is the second most common, behind Thinsulate, and has a fluffier feel.

Aerogel Adds Flexibility

NASA created Aerogel in the 1990s to help astronauts, but it later edged into mainstream boots.

This insulation is not as standard as Thinsulate but often combines with that insulation or others. Aerogel keeps feet warm in the winter and cool in the summer. It is a great way to make boots multi-purpose since they bring comfort in any season. The insulation is also highly flexible, so even new boots do not feel stiff. Aerogel is light, which gives even more comfort to the wearer. Since the materials are rare, they are more expensive. It's worth the cost for the right consumer.

Walking through snow in boots

Zylex Protects in Low Temperatures

If you are out in the bitter cold often, Zylex is an excellent material. It offers multiple insulation layers, protecting feet in even dangerously cold climates.

You get three or four layers of material, all varying in thickness. There are generally removable liners; clean or replace them as time passes. Zylex is an utterly weatherproof material that can withstand snow, freezing rain, sub-zero temperatures, and anything else you can throw at it. This type of insulation is often too much for most users, but it is worth considering if you are outside working, traipsing through dangerous conditions, or climbing a mountain in the snow.

Wool Resists Moisture

Wool has worked well as insulation far back in history, including in socks, sweaters, and even boots. It is a great way to go, but it has downsides.

Wool isn't weatherproof or water resistant. It is, however, lightweight and can act as a layer along with other materials for further comfort. Push it down and manipulate it; it readily forms to your foot. With this insulation, you don't have to worry about cold temperatures, but it's problematic when it's wet.

Terms That Fool You

You might see many different terms for the boots you want to buy. Before you buy something you think is good, you need to know what is what. Certain words may not mean exactly what you think they do.

Gore-Tex Seems Insulated But…

Gore-Tex does not mean insulation, contrary to popular belief.

While Gore-Tex is an excellent thing to have in boots, it does not mean insulation. Instead, Gore-Tex is a membrane that surrounds parts of the boot and keeps water from coming inside. At the same time, any sweat that occurs can escape from the boot. Gore-Tex pertains more to waterproofing, not insulation. You might see this term on jackets, gloves, hats, and other items beyond footwear.

While it is a good thing to feature on boots, it does not mean there are any insulating properties.

Thermaplush Sounds Like an Insulator But…

Thermaplush shows up in items other than boots, such as blankets.

It means an extra comfort layer around the foot on the innermost layer. The layer is soft, smooth, and has a velvet feel. It gives your feet a luxury in its soft comfort, but there is little insulating value. Thermaplush means soft comfort, not insulation.

Winter boots in the dirt

Measuring Your Insulation Levels

Grams measure the insulation in your boots, ranging from 200g to 2000g. The most common range is between 200g and 600g. The higher the number, the more insulation the boots have. The most common weight you will likely see is 400g, but it is essential to take note of the type of insulation and perhaps even the temperature rating of the boots. If you will be outside for any length of time, paying attention to insulation will benefit you.

There are often specific temperature ranges that go well with certain insulation levels. Some companies specialize in mild-weather boots, while others offer insulation for extreme cold.

For Short Trips Outside

Boots with the lowest level of insulation, 100g, work well for chilly evenings or warmer winter climates. Wear them three seasons of the year and expect to appreciate their cover anywhere in temperatures ranging from 40-50 degrees Fahrenheit.

For Limited Outside Work

Boots with 200g insulation, a lower level of insulation, work well for cold weather if you are constantly moving around. Your feet do not overheat in the mild temperatures but remain warm. With this level of insulation, you could take short winter hikes and play around outside in temperatures between 30 and 40 degrees F.

For Keeping Feet Warmer for Longer

The 400g level of insulation is the most common as it works well for higher levels of activity in cool weather but keeps your feet warm in cold weather, even if you are not quite as active.

If you had boots that were 200g in the past and were not warm enough, 400g might be just what you need. This insulation level works from 15 to 30 degrees F and can help you through the snow without feeling the cold. Enjoy a long hike or even sit outside with insulation at this stage.

For Extended Time Outside

When you move on to colder temperatures and more extended periods outside, 600g boots fit your needs. Remain active, and the boots allow your feet to stay dry and enjoy warmth at the same time. This type of boot is for extreme weather ranging from 5 below to 10 above. Sit longer or enjoy winter backpacking and other outdoor work without feeling the cold.

For Hunters/Skiiers/Hikers

An 800g insulation value is usually the highest level you want in your boots if you are active most of the time you wear them.

Insulation this high is an excellent choice for hunters sitting in a deer stand or workers withstanding cold temperatures throughout the day. Anything in the 800g range or above is better suited to frigid temperatures. Your toes are still okay, even without movement. Temperatures as low as 20 below are fine with this insulation.

For Those Who Sit/Stand Still

Your feet stay warm in harsh, cold conditions, even with low activity levels, when you have 1000g of insulation. If you know you are walking through snow or cold water, 1000g of insulation or more is a good idea.

For the Coldest Temperatures

If you are dealing with the coldest temperatures, rubber boots with 1200g insulation help you move through icy water and snow without feeling a thing. You also want to consider breathability when you get to this insulation level.

Snow on winter boots

For the Highest Levels Possible

If you need the most insulation you can get, 1400g insulated boots give you the warmth and comfort you need in those cold climates.

What About Socks?

When you have well-insulated boots, do you need to wear socks too?

Socks are usually a good idea for extra warmth and protection from moisture that may get in. Wool socks are breathable and moisture-wicking, which helps you hold warm at a lower temperature without keeping the sweat on your feet. You could also consider heavier socks with lighter insulation to get the right mixture of warmth and comfort.

The Upsides and Downsides of Insulated Boots

If you already know you want the look and style of a boot, or if there are practical reasons you want to get a new pair, it is a good idea to consider the pros and cons of the various insulation levels. You don't want to get something you aren't going to wear. Instead, think through the options and research so you're pleased with your purchase.


There are many advantages to insulated boots that make them well worth the price tag. Especially if you live in colder climates, they may just be your ticket to cozy feet!

Your Toes Stay Warm

The most significant upside to insulation in boots is that they help your toes feel nice and warm in the cold weather. They help more than a fluffy pair of socks and also help keep your feet dry.

Your Feet Remain Comfortable

Insulation has come a long way, and it is commonly lightweight and flexible while remaining comfortable. Any boots need comfort, or you will not want to wear them as expected.

The Boots Last Longer

Insulation performs well, but it is also often built to last. No one wants to buy boots with good insulation only to have warm feet for a short time before the insulation wears out. That is not how the different materials work.


While insulated boots can be a dream, they are not exclusively sunshine and rainbows. There are a few disadvantages that you should be aware of.

Feet Sweat More

If you wear insulation that is too high for the conditions and you're overly active, your feet can sweat and lead to discomfort. You need the proper insulation and breathability to prevent moisture from building up inside.

Two pairs of winter boots

More Insulation, Higher Costs

It is one thing to choose the proper level of insulation, but another to be able to afford boots that have it. Higher levels of protection cost more than average or low levels.

Temperature Rating Are Not Consistent

For legal reasons, many companies do not rate their boots based on temperature ranges. You might have to guess which insulation is best for the purposes you have in mind for the boots. You have to research to determine which insulation levels work for which temperatures.

Boot Height

Boot height and insulating qualities are something else you want to consider.

The insulation will not work if boots are too short and the snow and water get in from above. Low-cut or high-ankle boots work best for those who are highly active when wearing the boots, like hikers. However, colder-weather boots often come in over-the-ankle or mid-calf varieties. It only makes sense that the higher the boots go, the more of your body they cover and the warmer they will be. They also often have more insulation. The height can also help decrease the amount of snow, water, or dirt that can get in.

Warm Feet Fast

These options help you guarantee that your feet will be toasty in any condition:

  • Choose Higher Boots. Low boots are stylish, but you need something higher than the ankle for cold conditions to keep your feet in good condition.

  • Go With Moisture-Wicking Socks. Wet feet are a pain for many reasons, and they get colder faster as that moisture dries. Moisture-wicking socks help the boots do their job while your feet stay dry. Avoid cotton materials and go for wool or something else that helps keep things dry.

  • Look Into Breathability. Some boots insulate well — too well — and hot air inside can create sweat, which leads to discomfort. You want boots that have breathability to them. Avoiding nylon can help the feet breathe and stay warm at once.

  • Loosen the Laces. Many people tighten their laces as much as possible, which is counterproductive. Instead, keep the laces loose so air can escape and the feet can breathe.

  • Consider Gaiters. Gaiters are protective sleeve-like items that go over the leg and upper part of the boots to protect your feet from the rain and snow above. They help you to preserve your boots without adding bulk or weight. Take them on and off as needed in extreme weather conditions.

If you want winter boots for errands, 100g insulation works fine. If you like short hikes and walks during the colder weather, something more in the 200g range might work well. If you enjoy walking through the snow and being out longer, look at higher insulation levels.

Talk to the experts at any footwear store and see what they recommend, as the brands vary quite a bit.

Hiking with winter boots

Match Insulation to Your Needs

As you look for winter boots that meet your needs, insulation is one quality that comes high on the list of things to examine. Warm feet are vital whether you will be out for a long time or just for a few errands. Decide how you will use the boots and get insulating properties to match. Better yet, get different boots for different occasions!

Not everyone needs boots with the highest levels of insulation. That leads to sweaty feet and discomfort in some instances. The lower levels of insulation are perfect for certain occasions. Sometimes, trial and error help you to find what you need.

For more up-to-date info on the latest boot trends, styles, and purchasing options, check out BootAuthority.

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