In brief 💡
Four families of cooling fabrics exist today, and they don't work the same way.
- TechCool™ regulates temperature dry, through technical weaving, with no activation needed.
- JadeCool™ accelerates evaporation using jade micro-crystals, with UPF 50+ protection.
- PolyCool™ retains water for long-lasting freshness.
- PhaseCool™ absorbs heat through a phase-change material, with no soaking required.
The right choice depends on your activity, the humidity in the air, and how long you're exposed to heat. G-Heat has been designing these four technologies since 2017 to keep your body in its thermal balance zone, whatever the weather.
You're sweating heavily. And yet, the fabric against your skin stays cool. It's not really a paradox: a good cooling fabric doesn't fight sweat, it uses it. The evaporation of water on the skin's surface remains the body's most powerful cooling mechanism. A well-designed fabric simply amplifies what your body already knows how to do, or takes over when that mechanism falls short.
That leaves one practical question. Which one should you choose? Behind the word "cooling" lie four families of fabrics with radically different physical principles. One works dry, another needs water, a third holds onto it for a long time, and the last actually changes state to absorb heat.
This guide walks you through this Top 4, explained so you know which one truly keeps you cool for your situation, your effort level, and your climate.
How can a fabric actually cool you down?
Before comparing technologies, it helps to understand what happens at the surface of your skin. Your body maintains a core temperature close to 37°C (98.6°F) at all times. When heat rises, it dissipates the excess through two main channels: dilation of blood vessels beneath the skin, and above all, sweating.
It isn't the sweat itself that cools you down, it's its evaporation. Every gram of water that turns from liquid to gas absorbs a considerable amount of energy, drawn from the heat of your skin: roughly 2,450 kilojoules per kilogram of water evaporated. It's this energy draw that lowers surface body temperature. Once ambient air reaches around 30–35°C (86–95°F), this evaporative mechanism even becomes the dominant cooling pathway, since radiation and convection are no longer enough on their own. Under these conditions, your ability to stay cool depends directly on how fast your sweat evaporates.
When evaporation stops being enough
The problem is the air. When it's saturated with moisture, sweat no longer evaporates: it just runs off, without carrying heat away. Beyond roughly 80% relative humidity, the efficiency of evaporative cooling drops sharply. The body compensates by speeding up the heart rate and increasing blood flow to the skin, which tires you out faster and reduces performance.
A cooling fabric steps in at exactly these bottlenecks. Depending on the technology, it will speed up evaporation, extend it over time, or capture heat another way when evaporation alone isn't enough. The four families in this Top 4 correspond precisely to these four strategies.
Cotton: a false friend in the heat
A word about the benchmark to beat. Cotton is often the default choice in people's minds: natural, soft, breathable on paper. The trouble starts as soon as you sweat. Cotton absorbs moisture and holds onto it. Once wet, it dries slowly and stays plastered against the skin, which slows evaporation instead of helping it. A classic white cotton t-shirt also offers very weak UV protection, which drops even further once it's wet.
This is the starting point for cooling fabrics: doing better than cotton by actively managing heat and moisture. Cotton remains the counterexample here, never a solution. The four technologies that follow each take a different path to get there.
- Qmax quantifies how fast the fabric absorbs heat from your skin on first contact: ordinary cotton sits around 0.1 W/cm², while a high-performing cooling fabric exceeds 0.3 W/cm². The higher the value, the more pronounced the immediate cooling sensation.
- UPF measures a fabric's sun protection: a UPF 50+ garment blocks more than 98% of UV rays.
Each family in the range relies on one of these principles: JadeCool technology, PolyCool technology, and PhaseCool technology each have their own dedicated page, alongside the TechCool weave.
Also worth reading: Cooling sports t-shirt: G-HEAT proves the effectiveness of its technologies in a climate chamber
No. 1. TechCool™: dry freshness for intense effort
How many times have you skipped activating a cooling garment because you had to soak it before heading out? TechCool™ removes that hassle entirely. This first technology needs neither water nor activation. It works dry, continuously, from the moment you put it on.
The principle relies on a multilayer technical weave. The fabric's structure keeps air circulating constantly and manages moisture with precision: instead of holding onto sweat like cotton, these synthetic fibers push it outward, where it evaporates freely and quickly. Your skin stays dry, and cooling continues as long as you're moving, with no water source needed nearby. Wicking sweat away fast is the key to this light, breathable fabric.
Three properties drive the performance of this type of dry fabric, keeping you cool over a long effort:
- Breathability: the mesh lets air flow freely, both inside and outside the garment, for fast drying.
- Moisture wicking: sweat is pushed to the outer surface where it evaporates, instead of sitting against the skin.
- Odor control: by keeping the material dry, these synthetic fabrics limit bacterial growth and post-workout odors.
The go-to fabric for athletes
TechCool™ is aimed first and foremost at sport and sustained effort. Running, trail running, CrossFit, a long session under a dry sun: anywhere you sweat heavily and soaking a garment makes no sense. A men's cooling sports t-shirt in TechCool keeps up with your effort without ever turning into a wet weight, thanks to mesh panels that boost ventilation at the underarms. The women's version follows the same logic of light, fluid fabric.
This dry regulation also works wonders in dry professional environments, where there's neither the time nor the means to re-wet a fabric during the day. All of these pieces can be found in the cooling t-shirts collection, and to keep sweat out of your eyes while running, a TechCool cooling sports headband is a useful addition to your gear.
No. 2. JadeCool™: mineral-boosted evaporation and UV protection
The second family, and the best known in the range. JadeCool™ relies on evaporation, but sped up by mineralization. Its polyester fiber is embedded with jade micro-crystals, a mineral that naturally conducts heat.
The principle works two ways. On one hand, the jade conducts body heat outward through the fiber, producing an immediate, pleasant cooling sensation on contact, with a high Qmax. On the other, the activation water evaporates slowly, sustaining the cooling effect over time. Activation stays simple: soak the garment in water, wring it out, and it's ready. On fabrics in this range, this cooling effect can reach up to 15°C (27°F) lower on the surface within about fifteen seconds — a level of thermal control few natural materials can match.
It's a versatile fabric, built for everyday comfort: light and breathable, it keeps good airflow even once wet, unlike cotton, which gets heavy. Its polyester base with mineral crystals combines wearing comfort with cooling performance, indoors and outdoors alike.
The double anti-UV benefit
JadeCool™ is used in much of G-Heat's anti-UV fabric range, rated UPF 50+. One common mix-up worth clearing up: this sun protection doesn't come from the jade crystals, but from the fiber's dense weave. It's the fabric's density that blocks more than 98% of UVA and UVB rays, not the mineral. The two properties simply add up in the same garment: active cooling on one side, a UV barrier on the other.
The women's cooling anti-UV t-shirt in JadeCool sums up this dual promise: ultra-light and breathable, it cools while protecting exposed skin. The men's version covers the same needs, and to dress the youngest during family outings, the children's cooling anti-UV t-shirt in JadeCool uses the same technology with no added chemicals. This is the versatile fabric par excellence: city life in summer, the beach, family outings.
JadeCool™'s versatility doesn't stop at the t-shirt. For long days in the sun, the men's long-sleeve cooling anti-UV t-shirt in JadeCool covers more skin while keeping the same breathability and moisture management: the fabric lets air circulate and wicks sweat away without clinging to the skin. These high-performance synthetic products feel light and pleasant against the skin, unlike a natural fabric like cotton, which traps body heat. You'll find these pieces in the cooling t-shirts collection, and matching headwear to protect your head in the cooling caps and hats collection.
Learn more: JadeCool technology explained
No. 3. PolyCool™: long-lasting cooling through water retention
The third family, built for endurance. Where TechCool™ works dry, PolyCool™ takes the opposite approach: it holds onto water to release it slowly. Its super-absorbent polymer fibers soak up water on contact, up to 80% of their weight, then release it through slow evaporation.
The difference from JadeCool™ comes down to timing. JadeCool plays the immediate-cooling card, PolyCool plays the endurance card. Its reserve releases gradually, extending the cooling effect over several hours. This is the solution for prolonged, often static, exposure — out in full sun, when the cooling effect needs to last well beyond a few minutes. These super-absorbent materials are among the best suited to peak summer heat, where other fabrics run out of steam.
These products are built to last: the material keeps its properties season after season, and the effect stays comfortable as long as the reserve isn't fully dried out. A fabric you can re-wet in seconds to start a new cycle.
Where PolyCool shines
Spectators in the stands, festival-goers standing in the sun, a fixed outdoor workstation: anywhere you stay exposed for a long time. Head accessories, the most exposed part of the body, are the perfect illustration. A PolyCool cooling sports cap, light and breathable, keeps your head cool over a long outing once wet, with a front panel that concentrates the effect where it matters most.
For broader coverage of the head and neck, the PolyCool cooling anti-UV hat takes over. For highly exposed fixed positions, the PolyCool anti-UV safari cap adds a removable neck flap. And to cool the torso during static exposure, the PolyCool cooling vest goes the distance. These headwear pieces are gathered in the cooling caps and hats collection.
No. 4. PhaseCool™: phase-change cooling, no soaking required
The fourth and final family, the most technical and the most surprising. PhaseCool™ relies neither on the weave alone, nor on water. It uses phase-change materials, or PCMs, microencapsulated within the fabric as tiny capsules distributed throughout the fiber.
The mechanism is like an ice cube cooling a glass as it melts, just miniaturized. As temperature rises, the material shifts from solid to liquid, and this transformation absorbs the surrounding heat. As long as the material keeps changing state, it maintains stable thermal regulation, around 28°C (82°F) depending on the version. You don't experience heat spikes: the fabric smooths out the thermal sensation for two to three hours.
Cooling that's ready to go
The big advantage of PhaseCool™ is that it doesn't depend on evaporation. It works even when the air is humid, exactly where evaporative technologies start to falter. PhaseCool EVO cooling sleeves use a microencapsulation that works directly at room temperature, with no need to soak them first, to protect the forearms of cyclists or drivers exposed to the elements. Placed in the fridge or freezer for a few dozen minutes, they provide enhanced cooling for one to two hours. They can be reused indefinitely.
This family of fabrics targets situations where ventilation is lacking and heat is hard to shed any other way: enclosed environments, exposed job sites, extended time on the move. A cooling mechanism that depends neither on dry air nor on a water source — that's what makes PhaseCool™ unique among the four. Among the main benefits of these products: cooling that's ready to use instantly, a material that's reusable indefinitely, and consistent comfort even for people on the move all day. You'll find this piece and other arm-cooling options in the cooling sleeves collection.
Which cooling fabric should you choose for your situation?
You now know all four technologies. What's left is matching the right one to your situation. None of them wins on every front, and the right approach is to start from how you'll use it, not from the fabric itself. Three criteria are enough to decide: your activity level, your sun exposure, and the humidity of the surrounding air.
- You move around and sweat a lot (sport, sustained effort): TechCool™, which regulates dry without forcing you to soak your garment.
- You want immediate cooling plus UV protection for everyday life or a family outing: JadeCool™, which checks both boxes with its built-in UPF 50+.
- You stay exposed for a long time and stay still (stands, festival, fixed post): PolyCool™, which goes the distance thanks to its water retention.
- You're short on airflow and water (enclosed environment, mobility, humid air): PhaseCool™, which absorbs heat without depending on evaporation.
The table below sums up these four technologies side by side, with their mechanism, how they're activated, how long they last, and their ideal use case.
| Technology | Physical principle | Activation | Duration / performance | Ideal situation |
|---|---|---|---|---|
| TechCool™ | Passive regulation through multilayer technical weave | None (works dry) | Consistent while moving | Intense effort, running, dry environments |
| JadeCool™ | Evaporation accelerated by jade micro-crystals | Soak, then wring | Immediate cooling on contact (high Qmax) | Versatile, city, family, UPF 50+ protection |
| PolyCool™ | Water retention via super-absorbent fibers (up to 80% of its weight in water) | Extended soak, then wring | Several hours, slow evaporation | Prolonged, static sun exposure |
| PhaseCool™ | Phase-change material (PCM) absorbing heat as it melts | None on the EVO version (room temperature), or chilled beforehand | 2 to 3 hours of stable regulation (~28°C / 82°F) | Ready-to-use cooling, mobility, humid air |
The logic ultimately makes sense. You move a lot and it's dry: TechCool™. You want versatility and sun protection: JadeCool™. You stay in the sun for a long time without moving: PolyCool™. You want cooling with no fuss, in humid air: PhaseCool™. These four families don't compete with each other, they complement one another: nothing stops you from pairing a JadeCool t-shirt for your torso with PhaseCool sleeves for your arms on the same outing.
Immediate cooling or lasting cooling?
This is really the underlying question, the one that separates the four technologies. Some hit hard right away, others last a long time. Immediate cooling comes from contact, measured by Qmax: that's the domain of JadeCool™ and, partly, PhaseCool™. Lasting cooling comes from slow evaporation or water retention: that's the territory of PolyCool™ and, working dry, TechCool™.
For intense sporting use, you're looking for consistency: the fabric needs to keep up with the whole effort without flagging. For occasional exposure to a heat spike, you're looking for immediate impact. Matching the technology to the rhythm of your day is what separates a garment that truly cools you down from one that just doesn't feel hot. For versatile everyday use, the cooling clothing range combines these approaches depending on the piece, and the full set of cooling accessories lets you target the most exposed areas, head and arms first.
Also worth checking out: Comparison of the best cooling caps 2026: which models to choose and how?
Dry or humid: the real dividing line
If there's just one criterion to remember when choosing, it's this: air humidity conditions everything. The drier the air, the more effective evaporation is, and the more fabrics that rely on it deliver their full potential. TechCool™ and JadeCool™ are at their best in dry, well-ventilated conditions.
In very humid air, beyond roughly 80% relative humidity, evaporation slows down for everyone. That's where inertia-based technologies take the lead. PolyCool™ has a water reserve that releases slowly, and PhaseCool™ absorbs heat through a change of state, without depending on evaporation at all. Two different answers to the same problem of saturated air.
This logic explains why there's no such thing as a universal "best fabric." The motorcyclist stuck in traffic under blazing sun, the Sunday morning runner, and the spectator at a match in the stands aren't fighting the same heat, or the same humidity. Each has their own fabric.
Care: preserving performance over time
A cooling fabric is a technical product. Cared for properly, it keeps its effectiveness season after season. Treated poorly, it loses it fast. A few simple rules are enough to protect your gear.
- Wash cold or at 30°C (86°F) maximum: heat damages technical fibers, jade crystals, and PCM capsules.
- Never tumble dry: this is the most common mistake. The heat of the dryer drum permanently damages the fabric's structure.
- No harsh fabric softener on water-activated technologies: certain additives reduce absorption capacity, and therefore cooling performance.
- Air dry, flat or on a hanger, to preserve the durability of the fiber.
A fabric whose UV protection and cooling come from the fiber's structure itself, as with G-Heat, keeps its properties far longer than a simple surface treatment, which fades with repeated washing. That's a durability point that matters over the product's lifespan.
"People often ask us what the best cooling fabric is. The real answer is that there isn't just one. A runner, a gardener, and a motorcyclist don't have the same thermal needs. We developed four technologies precisely to cover these four realities, each with its own strength. Our job is to match the right physics to each use."
— Édouard Castaignet, Founder of G-Heat
Why choose G-Heat?
G-Heat has been designing thermoregulation garments since 2017. The brand was born out of a very concrete need — compensating for the body's thermal shortcomings — and extended that expertise to managing summer heat starting in 2022, with its first cooling technology.
The strength of the approach lies in the diversity of its technologies. Where many brands rely on a single process, G-Heat masters four complementary families. Each fabric is designed for a specific mechanism, a specific use, a specific duration. You're not choosing a generic "cooling" garment: you're choosing the technology that matches exactly your situation, your effort, and your climate.
Our logic isn't to pile on promises, but to match real physics to a real need. Keeping your body in its balance zone to extend your activity, whatever the weather: that's physics and fabric, not magic.
Clothing designed for every moment of the day
Whether you're heading out for a trail run at dawn, staying home during a heat wave, or walking around the city all afternoon, there's a fabric suited to it. Reducing the feeling of heat always comes down to choosing the right material at the right time:
- Sport and exercise: a TechCool™ t-shirt to stay cool without soaking your garment.
- Family outings and everyday life: a JadeCool™ anti-UV t-shirt, light and comfortable, to share between parents and kids.
- Static exposure: a PolyCool™ cap or hat to last for hours in the sun.
- Humid or enclosed air: PhaseCool™ sleeves, ready to use.
Conclusion
The best cooling fabric isn't the most sophisticated one, it's the one that matches your situation. TechCool™ for dry effort, JadeCool™ for versatility and UV protection, PolyCool™ for lasting cooling in static sun exposure, PhaseCool™ for ready-to-use cooling in humid air. Start from how you'll use it, how long you'll be exposed, and the humidity of the air, and let the physics do the rest.
Whatever the weather. G-Heat, whatever the weather.
FAQ: your questions about cooling fabrics
What is the best cooling fabric?
There's no single best fabric overall. TechCool™ excels for dry effort, JadeCool™ offers versatility and UPF 50+ protection, PolyCool™ lasts a long time in static sun exposure, PhaseCool™ cools without soaking and holds up in humid air. The right choice depends on your activity, your exposure, and the humidity of the air.
Does a cooling fabric really cool down the body?
A cooling fabric doesn't lower your core body temperature. It helps release heat more efficiently, by boosting sweat evaporation or absorbing ambient heat. The cooling sensation is real, but it acts on the skin's surface and on perceived comfort.
Is a cooling fabric more effective than cotton?
Yes, by a wide margin. Cotton absorbs moisture and holds it against the skin, which slows evaporation and leaves a warm, clammy feeling. A cooling fabric actively manages heat and moisture, either by wicking it away, absorbing it, or regulating temperature through a phase change.
Do all cooling fabrics need to be soaked in water?
No. TechCool™ works dry, with no activation at all. PhaseCool™ EVO sleeves activate at room temperature. JadeCool™ and PolyCool™, on the other hand, need to be soaked in water and then wrung out to release their cooling effect.
What does the Qmax value mean for a cooling fabric?
Qmax measures how fast the fabric absorbs heat from your skin on first contact. The higher it is, the stronger the immediate cooling sensation. Classic cotton sits around 0.1 W/cm², while a high-performing cooling fabric exceeds 0.3 W/cm².
Do cooling fabrics protect against the sun?
Some do, yes. JadeCool™ anti-UV garments are made of UPF 50+ fabric, meaning they block more than 98% of UV rays. This protection comes from the fiber's dense weave, not from the cooling technology. An anti-UV garment protects the area it covers: it complements sunscreen on exposed skin, it doesn't replace it.
How long does the cooling effect of a cooling garment last?
It depends on the technology and the temperature. TechCool™ stays effective as long as you're moving. PolyCool™ lasts several hours thanks to the slow evaporation of its water reserve. PhaseCool™ maintains stable regulation for two to three hours. JadeCool™ works mainly through immediate cooling on contact, to be reactivated as needed.
How do you care for a cooling fabric without damaging it?
Wash it cold or at 30°C (86°F) maximum, and never put it in the dryer: heat damages the fibers and crystals. Avoid harsh fabric softeners on water-activated fabrics, as they reduce absorption capacity. Careful maintenance preserves the technology's performance and durability.
The best cooling fabric isn't the most sophisticated one, it's the one that matches your situation. Start from how you'll use it, how long you'll be exposed, and the humidity, and let the physics do the rest.
Sources and references
[1] "Fortes chaleurs, canicule", Santé publique France (French national public health agency)
[2] "Travail à la chaleur. Ce qu'il faut retenir", INRS (French national research and safety institute)
[3] "Comment mieux se protéger du soleil ?", Institut national du cancer (French National Cancer Institute)
[4] "Vagues de chaleur : les équipes Inserm mobilisées pour mieux documenter les effets sur la santé", Inserm (French national medical research institute)
[5] "Canicule et forte chaleur : comment se protéger ?", Météo-France (French national meteorological service)
[6] "Recommandations sanitaires associées à l'index UV", Haut Conseil de la santé publique (French High Council for Public Health)
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