Understanding Boot Insulation

Understanding Boot Insulation

Insulated boots are meant to keep your feet warm while you walk, play, or work in the cold. There are various types and weights of insulation available on the market today and this can make it difficult to shop for the right boots. This post will help explain the different types of insulation and the weight necessary for specific weather conditions.

What Isn’t Insulation?

Let’s start with what isn’t insulation. You’ll see a lot “jargon” being thrown around when shopping for boots, including some terms that may confuse you, such as Gore-Tex and Thermaplush. There is such a thing as Gore-Tex insulation, but unless that is specified, you should make sure you aren’t purchasing a pair of boots that have a Gore-Tex membrane instead, which is put over boots in order to make them waterproof, but not insulated. While Thermaplush may “sound” like insulation, it is anything but. Thermaplush in the innermost layer of the boot, which is added to maximize comfort. Thermaplush does not have heating or heat-trapping abilities.

Thinsulate Insulation

There are various types of insulation available today for boots, but the most popular types of insulation are Thinsulate and shearling.

Thinsulate is by far the most frequently used type of boot insulation. Thinsulate provides excellent insulation, is extremely durable, and won’t break down easily. Thinsulate isn’t bulky or heavy and doesn’t lose its ability to insulate even when wet.

Thinsulate, similar to other synthetic insulations, traps air molecules within the microfiber. By trapping these air molecules the insulation is able to block out the entrance of the cold outside air. It also prevents heat from escaping the inside of the boots, keeping your feet nice and warm.

Thinsulate isn’t the only microfiber synthetic insulation available today, although it’s the most widely used. Other synthetic insulations include HeatSeeker, Zylet, OptiWarm, and Primaloft.

Shearling Insulation

Shearling Insulation is soft and snuggly, fine fleece. It makes the boots even more comfortable and helps keep your feet warm even in extreme temperatures. However, these boots are meant for general daily use, not rugged outdoor excursions.

Insulation Weights

Insulated boots come with different weights of insulation. Depending on the insulation weights the boots may be better for mild to freezing temperatures. Here are the insulation weights you’ll find when shopping for boots:


200 grams: Works best for cool temperatures and little to no activity, or for high activity levels in cold weather.
400 grams: Works best for cold temperatures when doing moderate activity.
600 grams: Works best for colder weather conditions and low activity levels.
800 grams: Works best for very cold weather and low activity.
1,000+ grams: Works best for extreme cold weather conditions with very little activity.


We hope this post has helped you better understand boot insulation and how to determine which is best for you.

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