· Pillows containing phase-change materials cool with some not-so-simple physics. They’re a bit more difficult cooling gel pillow to understand than the cooling effect of a bag of water.
The popular cooling gel pillow all work in 3 distinct ways:
· Breathable pillows enable air to flow freely throughout the pillow’s fill. They prevent warm air from building up.
The first cooling pillow’s design seemed reasonable enough. The concept is simple: you simply slide a plastic bag containing water, gel or other liquid into your pillow case on top of your existing bamboo pillow. There are several different brands and variations available, but most share the descriptive term, “cooling pillow insert.”
· Pillows containing water or gels cool your skin with the physics of conduction. You know what cool water feels like — the process of heat transferring from your body to the water or gel quickly makes your skin feel cooler. (note that some orthopedic pillow types are water based pillows. These are not cooling pillows)
PCM materials are capable of transferring heat both to and from your body. Heat is absorbed (or released) when the PCMs change from liquid to solid and vice versa.
I compared four products that represented the different approaches to cooling gel pillow design:
a water-based “cooling pillow insert” (a flat water bag that slides inside your existing pillow)
What’s the solution to this age-old problem? As it happens, there’s a ton of different cooling pillow designs that purport to keep you comfortably cool while you’re sleeping. Pillows containing phase-change materials cool with some not-so-simple physics. They’re a bit more difficult cooling pillow to understand than the cooling effect of a bag of water.
2. a memory foam pillow with a cooling gel layer
3. another memory foam pillow with a PCM bead infused pillow case
4. a pillow containing breathable buckwheat hull fill
Cooling Gel Pillow A Bamboo Pillow Insert (Water)
This was the cheapest cooling pillow option. I found a water-filled version for just 12 bucks. The bag is about 10×20″ and only about 1/2″ thick. One side of the insert has a soft flocked (textured) surface, which I assume is to help keep it from sliding around inside your pillow. Trying to sleep on a hot, sweaty pillow sucks. Repeatedly cooling pillow flipping to the cool side in the middle of the night isn’t the way to sleep!
I didn’t notice it until I unscrewed the water filling valve, but the bag contains a thin layer of polyester foam. When filled, the foam layer absorbs and retains much of the water. This helps to prevent the water from sloshing around to one part of the bag like a water bed does.