Coolmax vs Merino Wool: Key Differences!

When you’re sweating during your workout or outdoor adventure, nothing brings you down faster than wet, clammy clothing. You need activewear that expertly wicks moisture while letting your skin breathe.

But should you choose Coolmax or Merino wool? You might be wondering how Coolmax is different from Merino Wool, and how you should prefer one over the other.

To determine which fabric wins the Coolmax vs Merino wool showdown for your needs, you need to compare odor resistance, next-to-skin softness, sun protection abilities, and more.

The main difference between Coolmax and Merino Wool lies in their origin and performance. Coolmax is a synthetic, polyester fiber known for excellent moisture-wicking, breathability, quick-drying, and durability, ideal for warm climates. However, it’s less effective in odor control and not as eco-friendly. Merino Wool, sourced from Merino sheep, also handles moisture well, provides superior insulation even when wet, controls odors due to its antimicrobial properties, and is environmentally-friendly being biodegradable. Nonetheless, it’s costlier and requires careful washing to maintain form and longevity.

Overview of Coolmax

Coolmax is a brand name for a type of fabric that is designed to keep you cool and dry in hot and humid conditions.

Coolmax was developed in the late 1990s by DuPont scientists looking for an improved performance fabric.

They found that a unique four-channel fiber structure allowed for rapid moisture wicking, creating a cool and dry microclimate next to the skin. This innovative fiber shape gives Coolmax its key advantage over other technical fabrics on the market.

Coolmax is made of specially engineered polyester fibers that have a unique shape and surface that allow moisture and heat to escape from your body.

Coolmax is a popular choice for sportswear, activewear, and everyday clothing that require breathability and comfort. The specific properties of Coolmax fabric can be affected by factors such as the tightness factor, gauge, and yarn composition.

Coolmax Fabric Structure and Manufacturing Process

Coolmax fabric consists of finely spun polyester fibers shaped in an optimal structure to improve moisture wicking.

The unique tetra-channel or hexa-channel cross section of Coolmax fibers creates capillary action that pulls sweat away from the skin. This is a marked improvement over smooth, round fiber shapes that cannot spread moisture effectively.

The structure of Coolmax gives it superior wicking capability and quick-drying performance.

An intricate manufacturing process produces the unique capillary-enhancing structure at the heart of Coolmax technology.

Polyester chips become melted polymer, forced through special spinnerets to create the multi-channel fiber cross section.

The resulting fibers get crystallized, stretched, cut, carded, spun, knitted, and finished into moisture-wicking Coolmax fabric ready for activewear.

Coolmax is made using fine denier fibers which gives fabrics a soft, supple hand. There are two main types of Coolmax fiber used:

  1. Coolmax polyester staple fiber – This has a round cross-section and provides odor control but does not contribute to moisture management.
  2. Coolmax polyester filament yarn – This has a six-channel cross-section that provides both moisture wicking and odor control.

Comparison of Coolmax with Other Synthetic Fibres

When comparing Coolmax to other popular activewear fabrics, several key differences emerge:


Cotton, the go-to choice for casual wear, is a natural fiber that comes from the boll of the cotton plant. It’s soft, breathable, and great at absorbing moisture. However, once cotton gets wet, it stays wet. D

uring physical activity, damp cotton can feel heavy and chafe against the skin. Cotton also dries slowly, keeping moisture trapped against the body. For active pursuits, natural fibers like cotton are inferior to synthetics like Coolmax.


Polyester is a synthetic polymer fabric noted for its durability and stretch. Like Coolmax, polyester has good wicking properties to pull moisture away from the body.

However, the shape of the polyester fiber is round and smooth, which limits how quickly it can disperse moisture.

Coolmax’s unique grooved fiber shape spreads moisture out widely, resulting in super-fast drying time. Polyester is also less breathable than Coolmax due to its tight weave.


Another synthetic fabric, nylon is known for its light weight, strength and stretchiness. It shares polyester’s smooth, round fiber shape, so it cannot wick moisture as effectively as Coolmax.

Nylon also absorbs more water than polyester or Coolmax. For activewear, nylon is often blended with spandex for enhanced stretch and flexibility. On its own, nylon’s moisture management is less ideal for high aerobic activity.

In summary, Coolmax represents an innovative improvement in moisture wicking activewear. Its four-channel fiber has an ingenious shape that spreads moisture out widely for rapid evaporation.

This gives Coolmax an edge over natural and synthetic competitors in keeping you cool, dry and comfortable even through extreme perspiration. Brands like Under Armour, Adidas and others use Coolmax technology in their high-performance athletic apparel.

Uses and Applications of Coolmax Fabric

Thanks to its innovative fiber structure and moisture-management capabilities, Coolmax has become a featured fabric technology in the athletic apparel industry. The primary uses and applications of Coolmax include:

  • Sportswear: Coolmax is ideal for high-exertion sportswear like running, basketball, soccer, football, hiking, cycling, and fitness wear. It keeps athletes dry, cool and comfortable extending endurance and performance. Popular brands like Under Armour, Adidas, Reebok and others utilize Coolmax fabric in their activewear lines.
  • Outdoor apparel: For outdoor activities like camping, hunting, fishing, and mountaineering, Coolmax controls sweat and dries quickly to maintain comfort in adverse conditions. It’s featured by outdoor brands like Columbia, Marmot, and The North Face.
  • Base layers: Coolmax base layer garments like long underwear, leggings, and undershirts provide temperature control by wicking moisture from the skin during aerobic activity. Brands like Smartwool and Under Armour apply Coolmax technology in their base layer offerings.
  • Socks: Moisture-wicking Coolmax fabric is also ideal for athletic shoes, hiking boots, and performance socks helping to keep feet dry and blister-free. Brands like Adidas, Darn Tough, and Thorlo feature Coolmax in active footwear.
  • Workwear: Occupations requiring physical exertion in hot environments can benefit from Coolmax workwear, like protective gear for firefighters, military fatigues, and garments for industrial workers to help manage sweat and heat stress.

Coolmax vs Merino Wool Moisture-wicking Capabilities

When it comes to moisture management, both Coolmax and merino wool are excellent at wicking sweat and drying quickly. However, merino wool has a slight edge in terms of regulating body temperature.

The wool fibers absorb a high amount of moisture vapor, up to 30% of its weight, before feeling wet. This provides a cooling effect and buffers changes in temperature and humidity. Coolmax, on the other hand, doesn’t absorb as much moisture so it can feel clammy against the skin when saturated.

In terms of drying speed, Coolmax will dry marginally faster than merino wool. But merino wool retains much of its insulating properties when wet, whereas Coolmax loses some ability to retain warmth.

This makes merino wool more comfortable for activities like skiing or hiking in changeable weather. Coolmax is a great choice for runners and cyclists where faster drying time is optimal.

Personal Story

Last weekend, I convinced my friend Amanda to try a new hiking trail with me. Since the weather forecast called for afternoon thunderstorms, I wore my merino wool base layer but Amanda put on her usual Coolmax hiking shirt.

The morning started off sunny and hot. Amanda’s Coolmax wicked away sweat and kept her cool during the steep inclines. My merino regulated my temperature so I never overheated. By early afternoon, storm clouds rolled in and it started pouring.

My merino shirt absorbed the moisture and insulated me against the chill. But Amanda’s Coolmax became completely saturated. She was shivering and her shirt clung uncomfortably to her skin.

When we took shelter under a rocky outcrop, I stayed warm but Amanda couldn’t wait to change into the dry merino layer I offered her. After that day, Amanda saw why I always choose merino wool for activities where getting wet is a risk. Now she’s a merino convert too and won’t hike without it!

Coolmax vs Merino Wool Beathability and Ventilation

Coolmax fibers have a unique 4-channel cross-section which pulls moisture away from the skin and spreads it out across the surface area of the fabric, allowing it to evaporate quickly.

This construction gives Coolmax an excellent moisture wicking ability. It’s also a very lightweight and breathable fabric, making it ideal for high-intensity activities where you build up a sweat.

Now, onto Merino wool. For starters, Merino wool fibers have a crimped pattern which creates air pockets. This unique structure allows moisture vapor to pass through the fabric more easily.

The fibers of Merino wool are also hydrophilic, meaning they absorb moisture readily. As sweat is absorbed, it’s drawn to the surface of the fabric where it can evaporate. Lastly, Merino wool is antimicrobial which helps minimize odors.

So while both fabrics excel at moving moisture, they go about it in different ways. Coolmax relies on its synthetic fiber construction to spread out and evaporate moisture.

Merino wool uses its natural crimped fiber structure to allow moisture vapor to pass through the fabric.

When comparing the breathability and ventilation capabilities of Coolmax and Merino wool, it is important to consider the specific requirements of your activities and the prevailing weather conditions.

Coolmax excels in situations where moisture management and quick drying are crucial. Its synthetic nature and moisture-wicking properties make it an excellent choice for high-intensity workouts, hot climates, or activities that involve a lot of sweating.

The fabric’s ability to spread moisture across a larger surface area and promote evaporation contributes to its exceptional breathability and ventilation.

On the other hand, Merino wool shines in situations where temperature regulation and natural insulation are paramount. Its ability to trap air and provide insulation makes it an ideal choice for colder climates or activities that involve frequent temperature fluctuations.

The fabric’s moisture-wicking properties also contribute to its breathability and ventilation, ensuring comfort even during intense physical exertion.

In conclusion, both Coolmax and Merino wool offer excellent breathability and ventilation properties, albeit with different strengths depending on the specific requirements of your activities and the prevailing weather conditions.

Coolmax vs Merino Wool Odor Resistance

Over time, residues from sweat, body oils, and detergent can build up in the fabric leading to retained odors.

Merino wool has some natural advantages when it comes to odor control. For starters, the fibers in Merino wool have antimicrobial properties thanks to an amino acid called lanolin.

Lanolin creates a barrier on the wool fibers that makes it difficult for bacteria and body odor to cling.

The Merino wool fibers also absorb sweat without holding onto it. This allows body odor to be wicked away rather than absorbed into the fabric.

On the other hand, Coolmax uses a high-tech cross-section design to maximize airflow and cooling. This is key for reducing odor because dampness breeds bacteria growth.

Coolmax fibers are also treated with silver-ion technology that inhibits the growth of odor-causing bacteria.

So, in essence:

  • Coolmax dries very quickly, while Merino wool takes a bit longer to fully dry out. This could give Coolmax an edge for reducing dampness that leads to odor.
  • However, Merino wool’s natural lanolin layer seems to be highly effective at inhibiting bacterial growth. Even when damp, Merino resists odors better than synthetics.

Must Read: Best Merino wool socks

Coolmax vs Merino Wool Durability

Coolmax is generally considered to be more durable than Merino wool because it has stronger fibers that can resist abrasion and stretching better than wool.

On the other hand, Merino wool is less durable than Coolmax because it has weaker fibers that can break or tear more easily than polyester. 

Moreover, Merino wool has natural UV protection that prevents fading and degradation from sunlight exposure.

Also Read: Best Merino wool travel shirts

Personal story

My buddy Jeff is really into hiking and backpacking. Last year when he was shopping for a new base layer, he was trying to decide between merino wool and Coolmax. He ended up going with the Coolmax because he had heard it was more durable.

Jeff put that base layer through the ringer last summer on the Appalachian Trail – we’re talking months of daily use, sweat, dirt, and friction from his pack.

When he finally got home, that Coolmax shirt looked almost brand new while his merino layers were already showing some holes and thinning fabric. Jeff was glad he chose the Coolmax for its durability.

He said the extra lifespan is worth it since base layers can be pretty pricey. For hardcore outdoor use, Jeff will pick Coolmax over merino wool any day now that he’s seen firsthand how durable it is.

Coolmax vs Merino Wool Comfort and Feel

Merino wool is naturally very soft and flexible, with finer fibers than regular wool. It conforms well to your body shape and doesn’t feel scratchy.

Merino has a very fine fiber diameter that ranges from 16 to 24 microns. This makes it softer than most natural fabrics, including cotton, silk and regular wool.

Most people find Merino very smooth and gentle on their skin, even if they have sensitive skin or allergies.

Coolmax is also designed with comfort in mind – the polyester fibers wick moisture away from the skin efficiently.

However, some people find Coolmax has a slightly “plastic-y” feel compared to natural fibers. Overall, Merino edges out Coolmax in terms of all-day wearability and comfort.

The feel of a fabric refers to sensations like smoothness, crispness and stiffness. Merino has a very soft, fluid feel and drapes well. The fibers have a bit of natural crimp and elasticity, creating a pliable texture.

Coolmax is slick and smooth but has less drape. It can feel clingy when wet. The acrylic content in some Coolmax blends affects stiffness.

For mechanical stretch, Coolmax blends in elastane fibers. So when evaluating feel, Merino is more supple while Coolmax is smooth and a little stiff.

Merino wool contains keratin fibers that give it excellent stretch and recovery. The crimped structure allows the fabric to flex without breaking. Merino can stretch up to 30% of its length and snap back.

Coolmax doesn’t have the same natural elasticity as wool. But lycra and elastane are added to the fabric to provide mechanical stretch and recovery. The level of elasticity depends on the percentage blended in.

Overall, Merino provides better elasticity through the inherent structure of the wool fibers. Coolmax relies on synthetic elastane blends to achieve stretch.

As far as softness is concerned, Merino wool rates very high for softness, as the fibers are fine and flexible with natural oils. Coolmax uses very fine synthetic microfibers to enhance softness, but it’s not as naturally soft as Merino lambswool.

Modal or Tencel blends can be added to Coolmax to improve its softness. For some, Merino always feels softer due to being a natural fiber.

Overall, Merino provides exceptional next-to-skin softness that Coolmax cannot quite match.

Coolmax vs Merino Wool Environmental Impact and Sustainability

Compared to synthetics like Coolmax, merino wool is generally regarded as a more sustainable fabric choice.

Merino wool has a clear advantage here as a renewable fiber from a managed livestock source. Coolmax’s petroleum feedstock is non-sustainable.

Merino wool is a natural fabric that is renewable and biodegradable. Merino sheep can produce wool throughout their lives by grazing on grasses and drinking water.

When shorn, their fleece grows back within a year, ready to be harvested again. When disposed of, Merino wool can decompose in soil or water within a few months, releasing nutrients back into the environment.

Merino wool also does not contribute to microplastic pollution, as it does not shed synthetic fibers when washed.

However, Merino wool also has some sustainability challenges. For example, raising sheep can have negative impacts on land use, biodiversity, water quality, and animal welfare.

Sheep can overgraze pastures, causing soil erosion and desertification. Sheep can also produce methane, a potent greenhouse gas that contributes to global warming.

Sheep can also suffer from diseases, parasites, predators, and harsh weather conditions.

Some sheep are also subjected to mulesing, a painful procedure that involves cutting off skin folds around the tail to prevent flystrike.

Moreover, Coolmax contributes to microplastic pollution while Merino wool adds methane from sheep farming. There are impacts on water quality for both in processing.

If you are an eco-conscious consumer who wants to choose a fabric that can keep you cool and dry in hot weather, you may want to consider the following factors:

  • The source of the material: Is it made from virgin or recycled resources? Is it certified by a credible third-party organization?
  • The production process: How much energy, water, and chemicals are used to make the material? How are the emissions and wastes managed and treated?
  • The use phase: How often do you need to wash and dry the material? How does it perform in terms of comfort, breathability, odor resistance, and durability?
  • The end-of-life phase: How do you dispose of the material? Can it be reused, recycled, or composted?

Coolmax vs Merino Wool Cost Effectiveness

Coolmax is a relatively affordable technical fabric. It can be produced in high volumes at low costs compared to natural fibers. Pure Coolmax garments generally start around $20 for simple base layers.

More complex construction with added features raises the price, but it remains under $100 in most cases.

Merino wool has higher production costs than synthetic Coolmax. It is shorn from sheep primarily raised in Australia and New Zealand. Processing raw wool into fabric is labor-intensive.

As a natural fiber, Merino has more supply chain variability. This drives up prices. This is because sheep are shorn at certain times of the year based on natural growth cycles. This concentrates merino wool production during peak seasons rather than steady output year-round like synthetics.

Moreover, Merino wool shrinks when washed due to the scales on the fibers. This needs to be accounted for in manufacturing stages like dyeing. Synthetics have more predictable dimensions.

Entry-level Merino t-shirts start around $50. Mid-layer tops are $75 to $150, while high-end base layers and sweaters reach $200+. Outerwear and pants often exceed $300. So Merino comes at a premium compared to Coolmax.

Which is More Affordable Overall?

For single purchases rather than long-term wear, Coolmax generally provides better affordability. This makes it attractive for occasional use or seasonal layering pieces. The budget prices accommodate versatile layering systems.

Merino wool becomes more affordable when used frequently as part of a core wardrobe. The extended lifespan offsets the premium price. Merino works for minimalist packing on trips where clothing gets repeated hard use between washes. It also makes sense for people who are outdoors regularly year-round.

Coolmax vs Merino Wool Maintenance

Another factor to consider when comparing Coolmax and Merino is their maintenance. Maintenance refers to how easy or difficult it is to care for the socks and keep them clean and fresh.

Maintenance is influenced by how often the socks need to be washed, how they should be washed and dried, and how they should be stored.

Both Coolmax and Merino are easy to maintain fabrics that do not require much attention or effort. However, there are some differences between them in terms of maintenance.

First, Coolmax socks can be washed more frequently than Merino wool socks, since they do not retain much dirt or odor.

Coolmax socks can also be machine washed and dried without much risk of damage or shrinkage.

Second, Coolmax socks can be stored in any way without affecting their quality or performance.

Merino wool socks, on the other hand, may require more care and caution than Coolmax socks in terms of maintenance.

First, Merino wool socks do not need to be washed as often as Coolmax socks, since they have natural self-cleaning properties that keep them fresh and hygienic.

However, when they do need to be washed, they should be hand washed or machine washed on a gentle cycle with cold water and mild detergent. They should also be air dried or tumble dried on low heat to avoid shrinking or felting.

Second, Merino wool socks should be stored in a cool and dry place away from direct sunlight or heat sources to prevent moth damage or fading.

Coolmax vs Merno Wool FAQs

Which is better for cold weather, Coolmax or merino?

Merino wool is better for cold weather as it provides warmth even when wet. Coolmax lacks insulation.

Is merino wool itchier than Coolmax fabric?

No, merino wool is naturally soft and non-itchy while some synthetics like Coolmax can cause skin irritation.

Is Coolmax good for hot weather hiking and exercise?

Yes, Coolmax excels in hot weather as it wicks moisture and dries quickly to keep you cool during activity.

Which material is more eco-friendly, merino or Coolmax?

Merino is more eco-friendly as it is biodegradable and renewable. Coolmax is a synthetic material made from plastics.

Is merino wool clothing cheaper or more expensive than Coolmax?

Merino wool clothes tend to be more expensive than synthetic Coolmax which is cheaper to manufacture. But merino can offer more value long-term.

Is Coolmax or Merino Wool more suitable for hot weather?

Coolmax is generally considered more suitable for hot weather due to its ability to quickly wick away moisture and keep you cool. Merino Wool, although breathable, is better suited for cooler temperatures as it provides insulation and warmth.

Which material is more durable, Coolmax or Merino Wool?

Coolmax is known for its durability and ability to withstand frequent washing without losing its moisture-wicking properties. Merino Wool, while also durable, requires more delicate care to maintain its longevity.

Is Coolmax or Merino Wool more suitable for odor control?

Both Coolmax and Merino Wool have inherent odor-control properties. Coolmax’s synthetic fibers tend to be less prone to odor retention, while Merino Wool has natural antimicrobial properties that make it effective at reducing odor buildup.

Can I find Coolmax and Merino Wool in the same garment?

Yes, it is possible to find garments that combine Coolmax and Merino Wool. These blends can leverage the moisture-wicking properties of Coolmax with the insulation and softness of Merino Wool, providing a versatile option for various activities and climates.

Can both Coolmax and Merino Wool be machine washed?

Coolmax fabrics are typically machine washable and easy to care for. Merino Wool, however, requires more delicate care and is often recommended to be hand washed or machine washed on a gentle cycle.

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