What Is PCM and How Does It Keep You Cool?

Whether you're managing heat sensitivity from multiple sclerosis (MS), performing in heavy costumes under stage lights, or putting in long hours on outdoor job sites, staying cool isn’t just a matter of comfort—it’s essential. That’s where Phase Change Materials (PCMs) come in. It’s the science behind smarter, safer cooling solutions that help regulate your body temperature in even the hottest AND most humid conditions. But what exactly is PCM, and why is it such a game-changer for personal cooling?

PCM in Simple Terms

Phase Change Materials absorb and release thermal energy during melting and freezing. In other words, they act like a heat sponge—soaking up excess heat from your body and helping you stay cool, even in hot and humid conditions.

And here’s the cool part (literally): you’ve likely used PCMs before without even knowing it. Ice is a common phase change material—it freezes at 32°F (0°C) and starts melting at just above that temperature, absorbing heat as it does. Even something like butter is technically a PCM. It’s solid at room temperature but starts melting around 90°F (32°C).

How PCMs Help You Stay Cool

What makes PCMs so special for cooling is the amount of energy they can absorb while melting. The process of shifting from a solid to a liquid (or vice versa) is called a Phase Change, and this is where the materials get their name. This process requires significantly more energy than simply raising or lowering the material's temperature. This means PCMs can soak up a lot of excess body heat during their transition from solid to liquid, keeping you cooler for longer.

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At ThermApparel, we take this science a step further by using a bio-based, non-toxic PCM that’s optimized for personal cooling. Our PCM freezes between 66°F–70°F (19°C–21°C)—the ideal temperature range for comfort and safety, especially when worn directly against your skin.

Why Ice Isn’t Ideal for Body Cooling

While ice might seem like an obvious choice for cooling, it’s actually not a great solution for extended use on the body. Our core temperature hovers around 98.6°F (37°C), and our bodies constantly release excess heat to stay balanced. When the skin is exposed to very cold temperatures, like those from ice, our blood vessels constrict to preserve heat in the core. This means less blood reaches the skin—and in extreme cases, this can even lead to frostbite.

Not only does this vascular constriction limit the cooling effect, it also prevents cool blood from circulating where it’s needed most: to vital organs like the heart and brain. So, while ice may offer quick relief, it’s not the smartest choice for sustained cooling.

Why ThermApparel PCM Works Best

ThermApparel Cooling Packs are carefully engineered to work with your body—not against it. Because our PCM cools at a mild 70°F, it doesn’t trigger the body’s natural defense mechanisms. Your blood vessels stay open, allowing cooled blood to circulate efficiently through your system. The result? You feel cooler, longer, and more comfortably.

We also designed our cooling packs to conform closely to your body. This improves surface contact, meaning the PCM can absorb heat more effectively and begin working right away.

In Summary:

• PCMs absorb and release heat during phase changes (melting/freezing).
  
  

• ThermApparel uses a safe, skin-friendly PCM that activates at around 70°F.
  
  

• Unlike ice, this temperature works with your body, not against it.
  
  

• Better circulation means more efficient, comfortable, and longer-lasting cooling.
  
  

If you're looking for a smarter, safer way to keep your cool in challenging environments, ThermApparel’s PCM-based cooling is the way to go. With five easy-to-use PCM-powered cooling solutions, whether you’re working outside, cooking in a hot kitchen, or enjoying summer events, there’s a ThermApparel cooling solution tailored to fit your lifestyle

ThermApparel is a small business making big waves in the heat sensitivity world by designing the first lightweight, comfortable and invisible cooling vest, UnderCool. Check us out online, on our blog, or on Facebook, Twitter, Pinterest, LinkedIn and Instagram.

Please let us know if you have any other questions or ideas in the comments below, we will follow up. You can always reach us via:

Live Chat - www.thermapparel.com  |  Email - contact.us@thermapparel.com  | Phone - 855-232-7233 |  Address: ThermApparel LLC. 40 Franklin St. 4th Floor, Rochester, NY 14620