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What base layer should you choose?

January 19, 2024

The base layer is the foundation of your outfit, and it’s essential in regulating your body temperature and wicking moisture away from your skin when you are active. However, choosing a base layer can be overwhelming due to the various materials, weights, and designs available. In this guide, we will provide you with all the information you need to select the best base layer for your activities.

Different base layer materials

Synthetic materials

  • High-intensity activities

  • Exceptional moisture-wicking

Synthetic base layers are the go-to choice for high-intensity activities. They shine in moisture management by swiftly wicking away sweat from your skin and drying quickly. They are also durable, easy to care for, and can withstand rough use and frequent washing without losing shape or properties. This makes them the perfect all round base layer that you will grab for various outdoor activities.

However, there is one downside to synthetic materials like polyester - they may not be the best choice for long-term wear. They have a tendency to hold onto odours, and while they are great at wicking moisture away from the body, they may not be as breathable as natural fabrics. Moreover, in very cold weather, especially when wet, synthetic base layers may not provide the same level of insulation as merino.

Merino wool

  • Varying intensity levels

  • Odour-resistant and great for extended wear

Merino base layers are ideal for activities that involve varying levels of intensity. They excel at wicking away moisture and have the unique ability to regulate your body temperature, keeping you warm in cold weather and cool in warm weather. Wool has a high warmth-to-weight ratio and can keep you warm, even when wet, without being too bulky.

Additionally, merino wool is naturally antimicrobial and resistant to odours, making it suitable for extended use. Often, you won't need to wash your merino base layer after every use; simply airing it out will keep it fresh. Not having to wash it after every use is beneficial since wool requires more delicate care and is less durable than synthetic materials. It can more easily be damaged by abrasion or lose its shape when not washed properly.

Blended materials

  • Varying intensity levels

  • Durable and versatile

Many base layers are made from a blend of merino wool and synthetic materials like polyester. This mix makes the base layer more durable and more resistant to wear and tear, making it suitable for rough outdoor activities. The wool also enhances the base layer's insulation and odour resistance. So, with these blended materials, you get the best of both worlds and something you’ll want to wear for every activity.

How warm is the base layer?

The warmth of a base layer depends on several factors, including the materials used, the thickness of the fabric, and the design. Generally, wool base layers are warmer than synthetic ones, and thicker fabrics provide more insulation.

The weight of the material matters

Lightweight: The fabric weight ranges from 130g/m² to 180g/m², and they are designed for mild to cool conditions or high-intensity activities.

Midweight: Midweight options often fall in the range of 180 g/m² to 220 g/m². They provide more insulation and are suitable for colder weather or moderate activity levels.

Heavyweight: Heavyweight base layers have a fabric weight exceeding 220g/m² and are designed for extremely cold conditions or when you need maximum insulation.

The design also matters

The structure or finish of the fabric

The inside of the base layer fabric can affect how insulating the garment is. A waffle structure or a brushed interior creates tiny air pockets between the material and the skin. These pockets trap warm air, enhancing the garment's insulation properties.

Hood, balaclava, high neck and thumb grip

Staying warm on colder days means keeping your bare skin protected from chilly drafts. Wearing base layers with high necks, hoods, or integrated balaclavas can help shield your neck and prevent cold air from sneaking in. Additionally, using thumb grips can provide extra protection for your hands and arms. To keep those sleeves draft-free, simply wear gloves over the thumb grips.

Half-zip at the neckline

A base layer top with a half-zip is not only easier to put on, but it also has other useful benefits. During high-intensity activities, the half zip at the neck allows for ventilation when you start to get hot and sweaty. This is especially helpful if the intensity levels of your activity change and you don't want to bother with adding or removing layers.

Our base layers - warm, warmer, warmest

We love getting questions about our base layers and their warmth! Figuring out which is the warmest can be challenging, though, as it depends on a few things, like the material, weight, and design. But don't worry. We've compiled a handy guide ranking our base layers from warm to warmest. So, let's dive in and find the perfect option for you!

Fabric weightMaterialDesign
North Merino185g/m², MidweightRecycled polyester 70%, Merino wool 30%Brushed inside
Waffle220g/m², HeavyweightRecycled polyester 92%, Elastane 8%Waffle structure, ½ zip high neck
Outright180g/m², MidweightMerino wool 100%
Fuse MerinoMidweightViscose 30%, Merino wool 28%, Polyester 26%, Polyamid 16%Hood
Mount Merino180g/m², MidweightMerino wool 65%, Recycled polyester 35%
Sneaky BalaclavaMidweightPolyester 90%, Elastane 10%Balaclava
Uphill200g/m², MidweightRecycled polyester 84%, Elastane 16%

Choosing the right base layer

So, considering all this information, how can you choose the best base layer for yourself?

First, consider the material

Merino and synthetic blends: The most versatile material for base layers combining the performance of both synthetic materials and merino wool for durability, moisture-wicking, thermoregulation and odour-resistance.

Synthetic materials: The exceptional moisture-wicking properties of synthetic materials make them perfect for high-intensity activities.

Merino wool: The natural thermoregulation and odour-resistance of wool make it perfect for extended use during varying intensity and weather conditions. It is also more insulating than synthetic materials, so it keeps you warmer without adding extra bulk.

And then think about the weight of the fabric

The weight or thickness of the fabric is often a good indicator of how insulating the base layer will be. Generally, heavyweight base layers are more insulating than midweight ones, and so on. However, it's important to consider the materials and other features of the fabric as well.

The insulation you need depends on the temperature outside and how active you are. In colder weather, you'll need more insulation, while intense activity generates heat and requires less insulation. Here's a cheat sheet that you can use as a starting point:

Remember to always account for your own needs and preferences. If you often feel cold, you usually need extra insulation to keep warm. On the other hand, if you tend to feel hot, you typically need less insulation to stay comfortable.

And lastly, make sure the fit is great

When choosing a base layer, the fit is key to comfort. It should hug your body, ensuring efficient moisture-wicking and easy layering. However, don't go too tight – you want freedom of movement and proper circulation. A slightly longer top is smart; it covers your waistband and stays put during the action, keeping chilly drafts at bay.

For skiing, think about ¾ length base layer pants. They reduce fabric bulk inside your ski boots, enhancing comfort. And if you're wearing a backpack, those offset shoulder seams are a lifesaver, preventing annoying chafing on long treks.

The first step in the layering system

The base layer is just the foundation of the layering system. Its primary purpose is moisture management, but it’s also a crucial first step in keeping warm. Read our Layering Guide for more tips on how to layer for colder weather.

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