What Makes a Pillow "Cooling"? Materials, Technology and What to Look For
Almost every pillow on the market now claims to be cooling. Very few explain how, which is convenient, because a lot of them do it by putting a cool-sounding name on a fabric and hoping nobody asks questions.
A pillow genuinely sleeps cool when it does three separate jobs: it lets air move through the fill, it moves moisture away from your skin, and its surface draws heat off you on contact. Miss one and you get the pillow most people already own - aka the one that feels lovely for ten minutes and warm by midnight.
Why Your Head Gets Hot in the First Place
Your head is heavy, it sits in one place for hours, and it produces both heat and moisture the entire time. Underneath it, the pillow compresses. Air stops circulating in exactly the spot where you need it to circulate most.
That gives us two problems rather than one. Heat builds because it has nowhere to go. Moisture builds because your scalp and neck perspire through the night, and a sealed pillow holds all of it. This is why people flip their pillow. You're not looking for a colder pillow, you're looking for the side that hasn't absorbed your body heat yet, and a well-designed pillow removes the need for the ritual entirely.
Airflow Is the Foundation
Everything starts with whether air can physically travel through the pillow. A dense, solid fill blocks it, which is why a traditional block of memory foam so reliably sleeps warm. Structure, in other words, matters more than any coating applied to the outside.
We've approached this three different ways across our range, because different fills suit different sleepers. Our Hybrid™ pillow uses a core of small CertiPUR® verified foam Nanocubes®, which leave space between them for air to move. Our AeroDown pillow uses a Simba Renew Bio™ fibre core designed to support airflow. Three constructions, one principle: keep the inside of the pillow open, and heat cannot sit still.
The Fill Has to Handle Moisture Too
Airflow alone leaves half the problem unsolved. Damp fibres feel clammy even at a comfortable temperature, so the fill needs to move moisture on rather than hold it.
Our Simba Renew™ fibres are made from recycled bottles, combed and folded into soft, airy layers. The open structure encourages fresh air through the pillow, and it also gives the fill excellent shape retention, which matters more for cooling than it sounds. A fill that compacts loses the open structure that was doing the work. That's the real reason cheap pillows feel cooler in month one than month eight: nothing about the fabric changed, the loft collapsed and took the airflow with it.
Cool-Touch Technology on the Surface
The last piece is the surface your cheek actually rests against. Cool-touch finishes work by pulling heat away from the skin on contact and helping it disperse instead of accumulating.
Ours is Stratos®. Temperature testing* carried out by HeiQ in November 2020 compared Stratos®-treated fabric with untreated fabric and found it up to 3°C cooler; it's designed to feel cool to the touch, help prevent heat building up, and evaporate moisture. You'll find it on our AeroDown and Hybrid™ pillows.
*Temperature testing carried out by HeiQ in November, 2020 on Stratos®-treated vs untreated fabric to measure immediate and continuous cooling.
The Details That Finish the Job
Two smaller features do more than their share. The first is the cover. A breathable cotton cover lets air and moisture pass; a dense synthetic one can undo everything the fill is doing. The second is the border, the strip running round the pillow's edge. Our Hybrid® pillows use an open mesh border, so air moves in and out of the sides rather than being sealed in.
Washability belongs in the same conversation, since a clean, dry pillow stays fresher and performs better. Ours differ, so check the model: our AeroDown can be machine washed at 40°C and tumble dried on low heat, our Hybrid™ pillow's cover can be machine washed and tumble dried.
Your Sleeping Position Changes the Answer
Cooling isn't purely a materials question, because position determines how much pillow is in contact with you. Side sleepers need height to fill the gap between shoulder and ear, which means more material around the face and more opportunity for heat to gather. For them, airflow through the fill is the priority.
Front sleepers use a much flatter pillow, so there's less material to trap heat, but they press more of their face into the surface. Cover fabric and cool-touch finish are more noticeable there. This is one of the quieter arguments for an adjustable pillow: setting the height you actually need means you're not sleeping on more dense material than your position calls for.
How to Tell Real Cooling From Marketing
A pillow that genuinely sleeps cool will tell you its mechanism. Look for an open or structured fill, moisture-managing fibres, a breathable cover, a ventilated border, and a cool-touch finish with evidence behind it. The combination is the point, because each element solves a different part of the problem.
Be sceptical of anything described as cooling with no explanation of how, and particularly of a solid, sealed fill wearing a cool-sounding cover. If you sleep hot, a pillow designed to sleep cool should be doing all three jobs at once. Ours are built that way because we couldn't find a way to make one feature compensate for the absence of the other two.
FAQs
Three things working together: an open fill that lets air move through, fibres that carry moisture away so it can evaporate, and a cool-touch surface that draws heat off your skin. A pillow doing only one of the three will feel cool briefly and warm up as the night goes on.
Traditional memory foam is dense and effectively sealed, so air can't travel through it and your body heat has nowhere to go. Open-structure alternatives address this directly, which is why our pillows use foam Nanocubes®, foam FlexSprings™ or an airy fibre core rather than a solid block.
It does, within its remit. HeiQ testing* in November 2020 found our Stratos®-treated fabric up to 3°C cooler than untreated fabric, and it's designed to feel cool on contact and evaporate moisture. It performs best over a fill that already breathes, rather than over a sealed core.
*Temperature testing carried out by HeiQ in November, 2020 on Stratos®-treated vs untreated fabric to measure immediate and continuous cooling.
No pillow stays cold, and any that claims to is overselling. What a good one does is keep releasing heat and moisture instead of storing them, so you sleep at a steadier temperature and stop hunting for the cool side at 2am.
It depends which one. Our AeroDown can be machine washed at 40°C and tumble dried on low. With our Hybrid™ pillow, the cover is machine washable and tumble dryable.
