Your Boot Insulation Guide [With Temperature Rating Chart] | 200 vs. 400 G Insulation & What to Know

Cold weather doesn’t have to mean hanging up your hiking boots and hibernating until summer returns, but you may need to switch to insulated boots and carry winter hiking gear! Keeping your feet warm can help to keep the rest of your body feeling comfortable and strong when hiking, fishing, or simply enjoying time outdoors in cold weather. The easiest way to keep your feet from getting cold no matter how low the temperature drops is to invest in a pair of high-quality insulated boots. But how do you know which ones to choose, and how much insulation do you need? Here is your boot insulation guide:

 

The Importance of Boot Insulation

Cold feet aren’t just uncomfortable, they can impact the rest of your body. Without properly insulated boots, the feet (and toes in particular) can quickly become vulnerable to frostbite, circulatory issues, and other complications. Insulation creates a barrier against cold and dampness, preventing both from penetrating your boots even as you trek through snow and over ice. In addition to keeping cold out, insulated boots keep warmth in, preserving the warmth created by your movement and blood flow as you walk. In this way, insulation keeps your feet warm and dry, but not all insulation is made to stand up against extreme cold.

Choosing boots with the proper insulation for your specific needs is important, since underestimating the cold can have painful and potentially serious results. Similarly, wearing boots with too much insulation can cause excess sweating, chafing, and discomfort, adding extra weight and heat where it isn’t necessary. Because of this, most people stick to moderately insulated boots with ratings of 200-400 grams.

 

Types of Boot Insulation

While winter coats and jackets have many types of insulation, boots really only have two: shearling and synthetic insulation.

 

Shearling

Shearling is a type of leather from a sheep that’s just been sheared. The wool is left on as the leather is processed, creating a soft, snuggly, and incredibly warm material. Shearling is incredible insulation, but it does have a durability issue. It compresses and breaks down relatively quickly with heavy use, making it less than ideal for use on its own as a hiking boot material. Today’s shearling hiking boots are often made with other materials protecting the relatively delicate leather, but most heavy-duty hiking boots use synthetic insulation.

 

Synthetic Insulation

Most insulated boots use synthetic insulation. Thinsulate is the most common, but there are others, including Primaloft, Zylet, Heatseeker and Opti-Warm. All of these insulation types work the same way: microfibers trap air molecules within the insulation. The more fibers and the finer they are, the more air they trap. This mechanism significantly inhibits the movement of cold air molecules from the outside of the boot into the interior by keeping them trapped. Conversely, it also maintains the warm air molecules enveloping your foot inside the boot.

Thinsulate is the most popular because it has the finest, smallest fibers. This lets it trap a greater volume of air within a smaller space, making it ideal for boot insulation.

 

What Isn’t Boot Insulation?

As with many other types of hiking gear, there’s often a lot of jargon attached to boot descriptions. This can get annoying when buying insulated boots, because sometimes terms read as insulation, but actually aren’t. Two of the most common boot elements that look like insulation but aren’t actually insulation are Gore-Tex and Thermaplush.

Gore-Tex is part of many boots (and tents, jackets, and other pieces of waterproof outdoor gear). But it’s not insulation. Instead, Gore-Tex is a waterproof fabric membrane that keeps water droplets out of your boot. It has no insulating properties in and of itself.

Thermaplush might sound like insulation, but the key word is plush, not the therma-part. It’s an interior lining that’s velvety soft and cushiony, but not insulation.

 

Temperature Rating Explained

Winter and cold weather boot brands design their footwear to fit within specific temperature ratings, and then advertise them accordingly. Some companies specialize specifically in extreme cold-weather boots, whereas others may offer more moderately insulated options for city dwellers or mild weather.

Before you take temperature ratings too seriously, be aware that many companies create temperature rating estimates based on an unregulated series of assumptions. For example, most companies would say that a boot with 200g insulation could be worn in temperatures as low as -20 degrees Fahrenheit. This estimate is based on an assumption that the wearer would be moving the entire time and generating additional heat. If you plan to stand or sit still outside in -20, you would need boots with at least 600g insulation.

 

What does 400g insulation mean?

Boot insulation ratings refer to the thickness of the insulation used, not the total weight of the insulation in the boot. For example, a boot with 600g insulation would not contain 600g of insulation – that would be close to 1.5 pounds of extra weight. 600g insulation weighs 600 grams per square meter, which is the standard method of measurement for boot insulation. Similarly, 400g insulation weighs 400 grams per square meter, and 200g insulation weighs 200 grams per square meter. This does not mean that boots with 400g insulation will be twice as warm as 200g insulation. They will be warmer, but insulation does not scale like that.

 

Comparing Insulation Ratings

So, if you can’t rely on how brands rate their boots, how do you know how much insulation you’ll need? Before you start shopping for boots, familiarize yourself with the different types of insulation and what they can be used for. Remember, more insulation means more heat and more weight, which can be a positive or a negative depending on the circumstances. Here is a simple chart comparing the most common boot insulation weights:

 

If you only need winter boots for running errands during colder months, you’ll be fine in 100g insulated boots. If you are a nature lover who likes to take cold-weather walks and short hikes, you’ll want something in the 200g range. Longer hikes in snow and wet weather often call for 400g insulation, but you’ll want to go higher if you plan to sit still for any amount of time.

The above chart is of course dependant upon your specific needs. Some individuals simply don’t get cold feet easily, while others do. If you are one that often has issues with your feet getting cold, it may be a good idea to opt with a heavier insulated boot.

 

Socks and Insulated Boots

Even if your boots are insulated with soft, cuddly shearling, you still need to wear socks while you hike! And those socks must be moisture-wicking. Insulated boots are great at keeping the cold and moisture out of your boots– but that also means they are great at holding moisture in if your feet begin to sweat or if snow gets down into your boots. And while wet feet might be ok for a few minutes, hiking with wet feet will cause chafing and blistering. Obviously, this is not ideal.

Additionally, wet feet are harder to keep warm– even with good insulation. To prevent feet from getting cold as a result of dampness, consider wearing moisture-wicking socks. Avoid fibers like cotton, since these are extremely absorbent and can cause extra chafing and rubbing when wet. Merino wool is the best material for socks with insulated boots, since it’s naturally moisture-wicking, lightweight, thin, and has good insulating properties, even when wet.

 

Does Boot Height Matter?

Boot height comes into play when selecting boots for a variety of reasons. For example, someone who prefers extra mobility while hiking will likely prefer low-cut hiking boots over mid-cut or high ankle boots. Cold weather boots typically come in two heights: over the ankle and mid-calf.

High ankle boots will be warmer as they cover more of your body, and they generally have more insulation. In addition to this, the high ankle enables them to decrease the amount of dirt, snow, and water that can creep into your boots. When looking for a boot or shoe that is meant for winter conditions, you’ll likely want at least a mid ankle boot for this reason.

 

Best Insulated Hiking Boots

Now that you know some of the qualities to look for when purchasing a pair of insulated hiking boots, let’s compare some popular versions currently available. In the chart below, you’ll see a quick comparison of around 12 types of insulated boots and their specs. Notice that there are far more 200g options than 400g – this reflects the market in general, 200g has become standard. Choosing any of these quality boots will serve you well.

There are a few brands that do a great job of giving you insulation ratings, one of those brands is Rocky. Many of the boots designed for extreme cold are working style boots, mountaineering boots, or hunting boots that need to be insulated heavily due to lack of movement, or significant time spent on ice.

Tips for Keeping Your Feet Warm

If you choose the right pair of insulated boots, they will do the majority of the work of keeping your feet warm. However, boots alone won’t keep you fully safe from cold or moisture. In addition to wearing insulated boots, follow these tips to keep your feet dry and warm even when hiking in snow and freezing conditions.

 

Pick Mid-Calf Boots

The height of your boots will ultimately be determined by your personal preference, but if you are extra concerned about keeping your feet warm and dry, opt for a mid-calf option. Mid-calf boots give added protection against snow and help to trap hot air and prevent it from escaping. Over-ankle boots may provide similar protection but won’t help you to push through snow drifts or wet undergrowth. Mid-calf boots offer better protection from the elements, but don’t wear them if it isn’t cold where you will be hiking.

 

Wear Wicking Material Socks

Feet get wet while hiking for many reasons, whether it be due to snow, rain, or sweat! Wet feet aren’t a big deal for a few minutes, but hiking with wet toes all day can cause chafing, blistering, and serious discomfort. Additionally, wet feet can become extra cold, and may have trouble regaining heat once it is lost. To prevent feet from getting cold as a result of dampness, consider wearing moisture-wicking socks. Avoid fibers like cotton, since these are extremely absorbent and can cause extra chafing and rubbing when wet.

 

Consider Breathability

Some boots insulate too well, trapping hot air and humidity and creating a sweaty, messy situation with your feet. As mentioned above, wetness of any kind can create discomfort while hiking, which is why it is so important for your boots to have a certain amount of breathability. You may want to avoid rubber and nylon in some cases, since these insulate well but do not allow the feet to breathe.

 

Keep Laces Loose

Even if your boots are made from a breathable material, and you are wearing the appropriate moisture-wicking socks, you can still find yourself with sweaty, uncomfortable feet. A common mistake many hikers make is tying their boots too tight, believing that the tightness will help to keep them warm. While tighter laces may help to stop hot air from escaping, it also prevents moisture from evaporating. To allow your feet to breathe while keeping them protected, keep your laces as loose as you feel comfortable.

 

Wear Gaiters

Gaiters are protective ‘sleeves’ that go over the lower legs and upper parts of the shoes to protect them from dirt, rain, and snow. A good pair of gaiters can help to preserve the life of your boots, protecting them from unnecessary damage without adding extra bulk or weight. Easy to take on and off as necessary, gaiters come in especially handy during large snow storms or extreme weather.

 

Add an Insulating Liner

If socks and insulated boots alone aren’t keeping your feet warm, try adding an insulating liner. Liners are designed to resemble thick, boot-shaped socks that fit perfectly within standard boot sizes. Insulating liners help protect against cold and moisture and can be removed once warmer weather returns so you can wear the same boots year-round.

 

Bring Hand & Foot Warmers

Hand and foot warmers are extremely cheap, effective, and lightweight. Keeping them in your bag is a good idea, even if you don’t plan on using them. They can turn a miserable experience into a comfortable one if something unexpected occurs. Because of how little space they take up, we always recommend having a few in your bag. In addition to hand and foot warmers, companies do also make heated boots. This adds weight, but this is something that people utilize when they struggle to keep their feet warm even with insulated boots.