Tag Archives: polypropylene

Maybe you're an avid extreme winter mountain trekker or you simply get the chills while working in the cool office, you operate heavy mining equipment year round or you work for the US Coast Guard. Either way, thermal long underwear, also known as base layer or long johns, may be just what you need to stay warm and comfortable. The type you choose will depend on your activity level, your budget, and the temperature.

There are many types of thermal underwear but our customers usually choose one of these top three.

Merino Wool

Merino Wool thermal underwear is our warmest underwear. It doesn't itch or smell like regular wool can. It is very soft and comfortable against your skin. It wicks moisture away from your skin when you get wet. It also maintains its thermal properties, keeping you warm, even when it is wet. Best of all, it is made from natural materials that are environmentally sustainable. Merino sheep need a haircut once in a while just like you do - no harm done.

Polypropylene

Polypropylene is a popular material for thermal underwear because of its affordability. It is less expensive than many other options, but has many of the same benefits. Polypropylene will stay warm when it gets wet. It is durable and will last a long time. It dries very fast compared to other materials and it also wicks moisture away from the skin.

100% Cotton

100% Cotton thermal underwear and long johns are hands down some of the most comfortable, warm underwear you can get. It is very affordable, comes in a variety of colors and styles, and is made from renewable and natural fibers. The comfort and feel of cotton is hard to beat.

Trying to decide which type of thermal underwear is best often leads to thoughts about deep winter blizzards and hypothermia. Spring comes along and you stuff your base layers in the same storage bin as your heavy coat and snow gloves. When it comes to your spring and summer recreation, It's time to change your thinking about what thermal underwear is and when to use it.

Consider almost every other fuzzy animal that lives and dies based on its fur coat. When warm weather comes they don't shed every strand of hair and bask in the warm sun with no fur at all. Instead they shed their heavy winter coat and establish a lighter layer of fur to protect them from moisture, wind chill, and even the burning sun. So why do we humans suddenly ditch our common sense and put on a thin layer of non-insulating material as if that is the best option?

There are multiple lightweight or silk weight options that will expand your options beyond the cold temperatures of winter. The Duofold Varitherm Silk Weight thermal is an excellent example. It has a single layer, dri-release, poly/cotton blend that is designed to be worn during cool or warm weather. This makes it a realistic option 365 days per year. Silk weight thermals come in a variety of options including long sleeve, short sleeve, v-neck, tops and bottoms to suit your preference.

Many people want the insulating properties of thermal underwear without sacrificing the comfort they know and love from the feel of cotton. You don't have to shy away from cotton based thermal underwear under the assumption that it doesn't have the moisture wicking properties of wool. There are many cotton/polyester blends that will dry much faster than 100% cotton fabric. The cotton/poly blend also provides a wider variety of colors and styles including white, blue, black, red, camo patterns and more. Most of all you'll notice the considerable price difference in sizes for adults and even children. Many of the thermal underwear options on Outersports have been reduced in price due to the change in season. Don't miss out on a great opportunity to get the thermal base layers you need for any season or occasion.

Layering - How Does It Work

Layering to keep warm in cold weather is really a matter of insulating your body so that you retain your body heat. Layering typically consists of two to four thermal layers depending on the temperatures you'll be exposed to. Each layer is designed to trap air. The more air that is trapped inside a material or fabric, the better it will insulate. The two most common layers are a base layer or thermal underwear layer and an outer layer. Then, depending on your level of comfort and how cold the temperature is, you can add middle layers for extra warmth.

The great thing about layering is that it allows you to adjust your comfort level as temperatures change or as your activity level increases or decreases. As you get hotter, you can remove a layer. As you get colder, you can add a layer. Once you understand how layering works, you can adjust your own layering system based on your own comfort requirements and the weather conditions you'll be experiencing.

Layering - Types of Material To Wear For Each Layer

Now that you have an idea of how layering works, let's go over the different types of layers that will insulate you most effectively. Your first layer is your base layer or long underwear layer. Depending on the temperatures you're expecting to face, this layer can either be a thin single layer garment, a midweight two layer garment or a heavyweight two layer garment. As mentioned earlier, as you come to understand how layering works, you will know what weight or thickness you will need as a next-to-skin base layer. The type of fabric you wear is important. You need a material that will wick sweat, retain heat, and dry quickly. Some examples of the most commonly used materials are merino wool, polyester , and polypropylene. Each of these fabrics retain heat even when wet. Cotton thermals do not. The only time you'd consider using cotton is if you were not going to be very active.

Now, let's skip to the outer layer. The outer layer's job is to block wind, snow, or rain from penetrating your inner layers and robbing you of heat needed to keep you warm. Your outer layer would be a coat, jacket, or parka that is waterproof, windproof, and breathable. Many coats will have built in insulation while jackets and parkas may just be a shell with the option to zip in an insulating liner.

The reason I skipped to the outer layeris because what you wear in between the base

Pick The Correct Layer According To Temperature

layer and the outer layer all depends on your level of activity as well as how cold the temperature will be. A good base layer and outer layer is often sufficient for most winter weather conditions. During an average winter season, a good base layer and outer layer would be sufficient for skiing and snowboarding. However, if your combined base layer and outer layer are not warm enough, then you'll need to add an additional middle layer. This layer is typically a thicker layer of fleece. A merino wool, polyester or polypropylene fleece jacket and pants are recommended. A fourth layer is only needed in extreme cold weather conditions such as winter snow camping or summitting a high mountain peak. A fourth layer would be a heavyweight baselayer over a lightweight or medium weight base layer.

Layering - Thermal Base Layer Is Critical

Your next-to-skin thermal base layer is key to your comfort in cold weather. You want something warm, soft and dry against your skin.  Not just any fabric can give you this. Cotton is still a very popular as a base layer because it is so soft. The problem with cotton is that if you begin to sweat, it absorbs all of that moisture holding it next to your skin. Cotton does not dry very quickly. When it gets wet, cotton loses it's ability to retain heat. This condition can lead to hypothermia if exposed long enough.

You need a performance fabric like merino wool, polyester, or polypropylene. Merino wool thermal underwear is super soft and 100% natural. It does a great job of managing moisture and keeping you dry. It also retains heat even when wet. It costs more than other thermals, but is well worth the price. Polyester and polypropylene are very similar. Both can be spun into a very fine thread making it extra soft and comfortable. Both of them are hydrophobic which means they repel water and dry quickly. Polypropylene retains more heat than any other fabric and it dries much quicker too. Polypropylene is probably the least expensive of these performance layering fabrics.

Layering - It's Never Too Cold With The Right Layers
Now that you know how to layer properly in cold weather, you can go out and enjoy the winter season. Don't be like so many others that sit inside depressed all winter long because they hate the cold. There is plenty of fun to be had throughout winter. All you need is the right layers!