This piece of essential bedding could be making your mattress too warm — here's how you can fix that

Safeguarding your bed against spills, sweat, and stains is an essential part of sleep health. This not only gives you peace of mind but also reduces damage to your mattress and extends its lifespan. However, what if I told you this may also be the reason behind overheating in bed?

Waterproofing is a major function of some of our best mattress protectors. These are specially designed with a waterproof membrane that’s great at blocking liquids. The problem? They're not breathable enough, which can leave you hot and stuffy, even if you sleep on one of the best mattresses.

The good news is that you don’t have to choose between waterproof protection and comfort, as in this article, I'll explain why some mattress protectors trap heat and the steps you can take to avoid that. Let’s get right into it then…

How does a waterproof mattress protector make your bed warmer?

The secret element behind a waterproof mattress protector is a barrier usually made of cheap plastic or vinyl, which can potentially trap heat. According to mattress manufacturers like Puffy, the vinyl or dense plastics used in these toppers reduce airflow and thereby increase the temperature.

The effect is two-fold, especially when you pop on a heat-trapping waterproof mattress protector over a memory foam bed. This is more often than not a recipe for disaster since memory foam is also infamous for retaining heat, leading to night sweats and disrupted sleep.

(Thanks to modern sleep tech, the best memory foam mattresses we have tested in 2025 include cooling elements incorporated to dissipate heat and deliver a restful sleep.)

3 signs your mattress protector is making you sleep hot

Now that we understand how a waterproof mattress protector can contribute to overheating at night, how can you know for sure it's the reason you're waking up sweaty? Here are three tell-tale signs:

• Waking up hot or sweaty: If you're not someone prone to overheating, yet you've tried adjusting thermostat settings and still wake up sweaty night after night, your waterproof mattress protector may be to blame.
• Mattress feels warmer than usual when lying down: Does your bed have a comfortable neutral temperature, but is suddenly warmer once you pop on the waterproof mattress protector? It's probably time to reevaluate your bedding.
• You sleep better without it: This is the best way to confirm whether your waterproof mattress protector is really at fault. If you sleep better and the only change you've made is removing the mattress protector, you've solved the riddle.

How to balance protection and comfort with a waterproof mattress protector

1. Look for a waterproof mattress protector with breathable materials

Fortunately, not all waterproof mattress protectors will make you overheat during sleep. The idea is to choose ones using breathable materials like plant-derived Tencel-Lyocell. These not only promote airflow but also wick away moisture, so you can say goodbye to sticky beds and stuffy nights.

Our top cooling option in the guide, the Brooklyn Bedding Luxury Cooling protector, for instance, includes high-tech PE fibers which, in our reviewer's words, proved to be "consistently cool-to-touch." If you're a hot sleeper, it's ideal to go for protectors like the above, which use active cooling elements to dissipate heat.

2. Pair it with cooling bed sheets

Don't want to swap your new protector for another right away? The alternate option is to pair it up with cooling bed sheets. These are usually crafted from sustainable fabrics like cotton, linen, bamboo, or hemp, which are naturally breathable and moisture-wicking.

While choosing bed sheets, pay attention to the thread count in addition to the material, as this can significantly alter the feel of your bed. Sheets with a higher thread count might mean superior quality, but a dense weave will warm up the bed, which is exactly what you're trying to avoid.

Since your bed sheet is the top layer directly in contact with your body, using breathable fabrics here will counteract your waterproof mattress protector so your bed doesn't feel like a sauna.

3. Use a cooling mattress topper

This can work well for your sleep in two ways. A cooling mattress topper will enhance the comfort and cushioning of your mattress while preventing any heat buildup.

Our best cooling mattress topper, the Molecule Copperwell, scored a perfect 5/5 for temperature regulation. Its cooling copper infusion and open-cell construction dissipate heat. Combined with an ergonomic design, our tester enjoyed nights of cooler, more comfortable sleep in our Molecule Copperwell Mattress Topper review.