How Do Cooling Mattresses Work? The Secret to a Cooler, More Restful Night’s Sleep
By M H Dodick
Cooling mattresses work in one of two ways: active systems that use water or air circulation to continuously pull heat away from your body, or passive materials, like cooling gel, open-cell foam and moisture-wicking fabric, that resist heat buildup and let it dissipate naturally instead of trapping it against your skin. Endy’s mattresses take the passive route: cooling gel and breathable open-cell foam (plus pocket coils in the Endy Hybrid mattress) are built into every layer, so heat can escape instead of building up under your body all night.
Active vs. Passive Cooling: What’s the Difference?
When people ask how cooling mattresses work, they’re usually thinking about two different technologies.Active cooling systems, like water-circulation pads, use pumps to continuously move heated or cooled water or air through tubing built into a mattress topper. They actively regulate temperature and can hold a set surface temperature electronically all night long.Passive cooling mattresses don’t plug in. Instead, they rely on materials engineered to regulate body temperature on their own: cooling gel that absorbs and disperses body heat, open-cell foam that lets air move freely, pocket coils creating physical air gaps, and breathable, moisture-wicking covers. Rather than actively lowering body temperature, these materials prevent heat from getting trapped in the first place.Endy’s mattresses are in the second, passive cooling category.
What Materials Actually Make a Cooling Mattress Work?
Cooling Gel
Gel-infused foam is one of the most common cooling technology upgrades in cooling mattresses today. Instead of trapping body heat the way traditional, closed-cell memory foam can, gel-infused foam absorbs excess body heat and disperses it across a wider surface area rather than letting it concentrate under one spot. That’s why gel foam feels cool to the touch the moment you lie down.
Open-Cell Foam
Traditional memory foam uses a closed-cell structure, meaning air and heat get trapped inside individual foam cells. Open-cell foam doesn’t. It’s built with an interconnected network of air pockets that let air flow through the foam instead of pooling under your body. Every foam layer in both the Endy Mattress and the Endy Hybrid uses open-cell foam. Breathable materials like this are why Endy’s foam mattresses avoid the trapped-heat feeling common in older-style foam mattresses.
With open-cell foam and gel-infused foam layers, the Endy Mattress is built for cool sleep. Shop the Endy Mattress
Pocket Coils
Zoned, individually wrapped pocket coils, like the ones in the Endy Hybrid, create physical air gaps beneath the foam layers. Air can travel through and around the coil layer, allowing heat to escape. This is why a hybrid mattress with coils generally sleeps cooler than an all-foam mattress of similar construction: not because coils are colder, but because they feature an airflow pathway supporting better heat dissipation than foam alone.
Moisture-Wicking Covers
Breathable, moisture-wicking mattress covers pull moisture away from the skin so it can evaporate, which helps you feel more comfortable. For clarity: a breathable cover manages sweat but isn’t a heat-removal layer on its own. It works with the foam and coil layers underneath, not instead of them.Some mattresses also use phase-change materials, which absorb and release heat as they change physical state. However, Endy’s approach centres on open-cell foam, cooling gel, and with the Hybrid, airflow-driven coil support.
Endy Mattress vs. Endy Hybrid: Which Mattress Sleeps Cooler?
Both Endy mattresses share the same cooling foundation, but the Hybrid adds one extra layer of ventilation, pairing foam with coils like most hybrid mattresses.The Endy Mattress is all-foam: a single layer of gel-infused Endy Comfort Foam sits above the pressure-relief and support foam layers, topped with a breathable, moisture-wicking cover. Its cooling effect comes from the foam’s open-cell structure and gel infusion.The Endy Hybrid builds on that foundation with Endy Comfort Foam in the top comfort layer and the quilted cover, plus a zoned pocket coil support layer underneath. Those coils add airflow channels an all-foam mattress can’t replicate: that’s why hot sleepers often prefer a hybrid mattress.So, the Endy Hybrid tends to feel cooler than the Endy Mattress because it adds an extra airflow pathway on top of the same gel-and-foam structure.
Who Actually Needs a Cooling Mattress?
A cooling mattress tends to matter most for people who:
Sleep hot despite the season
Deal with night sweats
Don’t have reliable air conditioning
Have a sleep partner (since two people in one bed means twice the body heat to manage)
Passive cooling materials work best paired with breathable bedding and a cool room (ideally about 15.6 to 18.3 degrees Celsius) for restful sleep and healthy thermoregulation.
What Cooling Mattresses Can (and Can’t) Do
Gel-infused and open-cell foam reduce heat buildup compared with dense, closed-cell memory foam, but they work by preventing heat retention, not by actively lowering body temperature as an active cooling system would. Gel-infused foam typically feels noticeably cool for the first 20 to 45 minutes, then settles into a more temperature-neutral feel as your body and the mattress reach equilibrium.However, a cooling mattress can’t compensate for a hot sleep environment, so lower the temperature in your room and use breathable sheets for better sleep. For a full breakdown on how to sleep cooler, read our ultimate cool sleep guide here.
Cooling Mattresses Buyer’s Checklist
If you’re looking to buy a (passive) cooling mattress, here are the features to look for:
Cooling gel-infused foam
Open-cell foam
Pocket coils (if you are buying a hybrid mattress)
Breathable, moisture-wicking cover
The Endy Mattress and Endy Hybrid combine the above features for a cooler night’s sleep. It also includes a 365 night trial and 15-year warranty so you know your purchase is protected.
Frequently Asked Questions
How do cooling mattresses work?Most cooling mattresses work by resisting heat retention rather than actively lowering temperature. Cooling gel, open-cell foam and pocket coils help move or disperse body heat instead of trapping it against your skin.Do cooling mattresses really make a difference?For most hot sleepers, yes. Passive materials, like cooling gel and open-cell foam, measurably reduce the heat buildup common to dense, traditional foam, even though a passive cooling mattress doesn’t refrigerate the sleep surface as an active cooling system does.What’s the difference between the Endy Mattress and Endy Hybrid for hot sleepers?Both use the same gel-infused, open-cell foam. The Hybrid adds pocket coils for extra airflow, which many hot sleepers and couples prefer.Can a mattress topper make a warm mattress sleep cooler?A gel-infused or open-cell foam topper adds a layer of temperature regulation, though it won’t fully offset a mattress that already traps heat.Does a cooling mattress replace air conditioning or a fan?Not necessarily. Passive cooling mattresses reduce heat buildup at the sleep surface; they don’t lower room temperature. A fan or AC may still be necessary for your comfort.
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