Merino wool. Merino base layers are considered by many (including me) to be the best type of fabric for long johns in extremely cold weather. Merino base layers are excellent for almost all weather conditions. They quickly wick moisture and are naturally odor resistant.
Thermos are great because they retain body heat better than your jeans or men’s shirts when it’s incredibly cold. The best thermal clothing also wicks away sweat so you don’t get cold. So you don’t freeze as quickly when shoveling snow as you would without thermal clothing.
Heavy base layers have thicker fabrics that keep you warm at all times. Overall, this extra insulation makes them the best cold-weather base layer.
For maximum insulation, thermal clothing should fit snugly against the body with no gaps around the waist, neck or wrists. Thermals that are too tight cause discomfort, but if thermals are too loose you risk cold air seeping through your layers. Loose thermals are suitable for warmer conditions.
Merino wool is the best material for thermals. For maximum warmth, wool, specifically from Merino sheep, is the best choice for thermal underwear. According to Smartwool, merino wool is ultra-thin – one-third the diameter of a human hair – and soft, unlike the prickly, itchy feel of traditional wool.
Think of it as the latest underwear-than-outerwear trend: thermals – those things that are usually hidden under clothing in sub-zero temperatures – can now be worn solo.
It integrates one of the world’s lightest yet incredibly insulating solid substances – Aerogel – into a jacket’s lining and claims to create the world’s thinnest, warmest and most breathable coat ever. Airgel is not new.
Synthetic: Lightweight and made for extreme cold, synthetic fabrics are the material of choice for thermal clothing. Made from polyester, spandex, nylon or lycra, these are often blended with another synthetic or natural fiber for excellent heat retention and moisture wicking properties.
While some may argue that there is a difference between a thermal and a base layer, they are essentially the same thing. Whatever you want to call them, thermos are designed to wick away moisture, regulate your body heat and stretch so you can move freely.
Thermos are a perfect pair of pajamas as they fit snugly and don’t allow your body heat to escape. This keeps cold air out, so you don’t need as many blankets as you’re used to. If you wake up sweaty in the morning from too many blankets, consider a women’s thermal underwear set.
Wear thermals at night
You should also take a look at the inside temperature in the evening before you go to bed. If you find that the temperature is below 18°C, you should sleep in your thermal pants.
You only need about two to three pairs of long underwear. You may want to buy more depending on your style and how often you wear them. Also keep in mind that many long johns come in a variety of colors and styles. They will be light but still fit your body like a second skin.
Protein fibers work synergistically with our skin to form an insulating second skin that warms to our body temperature. Silk is better than merino wool because it dries faster and allows the skin moisture that causes heat loss to evaporate more easily. Silk layers are also very strong and won’t go into holes like merino.
A base layer is the layer closest to your skin and should act like a constant “second skin” throughout the day. Underwear provides a warming layer and absorbs and evaporates your sweat to keep you warm and comfortable.
1. Wool. Make sure you stock up on wool sweaters for winter – this fabric is the warmest you can find. As you probably know, wool comes from sheared sheep (and sometimes other animals).