Do Kapok Pillows Sleep Hot? Notes From a Room With No AC

Short answer, for the people who came here with sweat on their neck: no. A kapok pillow is one of the coolest pillows I've slept on, cooler than every foam pillow I've owned and cooler than down. Here's why.

I spent four months in Hawaii designing these pillows in a house with no air conditioning. Trade winds through open windows most nights. Some nights, no wind at all, which in a tropical climate is when you find out what your pillow is really made of. I slept on a lot of prototypes in that room. The kapok ones were the ones I kept.

Why kapok runs cool

Kapok is a plant fiber, a silky floss that grows in the seed pods of the ceiba tree. Under a microscope each fiber is a hollow tube with very thin walls, and researchers have measured the fiber at up to about 80 percent air by volume, which is why it's so light and why it floats. A 2021 review in Oriental Journal of Chemistry reports a measured porosity of about 77 percent. I wrote the full background in what is kapok.

Air is what matters here. A memory foam pillow is a solid block. It's dense, it's in full contact with your head, and it's designed to warm up and soften, which is the whole mechanism of memory foam. The heat from your head goes in and mostly stays. The Sleep Foundation calls memory foam notorious for trapping heat. Kapok is the opposite kind of object. It's a loose mass of hollow fibers with air moving between them and air inside them. Your head sinks in, the fill cradles without hugging, and the heat has somewhere to go.

Down is also a loose fill, but down is an insulator by nature. It's what birds use to stay warm. Kapok isn't built to trap heat. It's a fiber that evolved to carry a seed on the wind.

What the cotton adds

Our pillow shell and the separate zip on cover are both organic cotton sateen. Cotton breathes and pulls moisture away from your skin, which is most of what "sleeps cool" means in practice. Cotton Incorporated describes it the same way: humidity passes through the fabric instead of sitting against your skin. Sateen gives you that smooth, soft hand. If you love a crisp feel when you lie down, slip a percale pillowcase over the cover and you get both. I went through that choice in sateen vs percale.

The loft lever nobody mentions

Every pillow's height affects how warm it sleeps. Ours has a zipper, so you control it. Pull a handful of fill out, store it in the bag, and the pillow gets lower and airier. My guide to pillow loft covers how to find the right amount for how you sleep.

If you run hot, this is what I'd do

Start with a little less fill than you think you need. Use the zip on cover to protect the pillow and a cotton pillowcase over that, percale if you like crisp. Wash the pillowcase often, because a pillowcase full of a week of sweat and hair product is going to feel warm no matter what's inside. Keep air moving in the room if you can; a fan and a kapok pillow are a great pair.

Then sleep on it through a warm month. The pillow comes with a 100 day sleep trial, so you can try it in your room, in your weather.

See the MAREA kapok pillow · Kapok pillows for hot sleepers

Anthony
Founder, MAREA Sleep

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