We asked experts whether cooling bedding works. Here’s what they said.

Americans are facing a hot summer. If you already struggle with overheating at night, you may be intrigued by the abundance of mattresses and other sleep products that claim to be “cooling” — an enticing prospect for those sweating through their sheets.

The proliferation of cooling products is a response to the rise of foam-based mattresses, experts say. Traditional innerspring mattresses tend to stay pretty cool because their design allows for airflow. But when memory foam began flooding the market, consumers realized how stuffy they felt.

Companies adapted by tinkering with their models. They had good reason to do so: There is evidence that cooling can aid in sleep quality, says Alison Kole, founding medical director of Oak Health Center Sleep Program and host of the podcast Sleep is My Waking Passion.

But the array of options can be overwhelming. As one user posted in the Reddit group r/mattress, “This is ruining my life, just tell me what the [expletive] to buy.”

It’s made even more challenging by the lack of standardization within the industry. “Cooling is an unregulated term, and everyone takes it to kind of mean a different thing,” says Grace Wu, a product analyst at the Good Housekeeping Institute.

And there’s no shortage of chatter on social media about all of the options, further muddying the waters. There are active Reddit groups devoted to specific brands (r/bedjet and r/eightsleep), as well as the more general r/mattress group, which has 80,000 members. It’s enough to make you dizzy.

We’re here to help you find your way in the forest. Understanding the basic technologies is a good starting point.

Cooling mattresses

On a basic level, the more air that can flow through a mattress, the cooler it’s going to stay, says Derek Hales, CEO of sleep product review site NapLab. A spring mattress will be cooler than a hybrid mattress, which uses both coils and foam. A hybrid will generally be cooler than an all-foam latex mattress, and latex is more breathable than memory foam.

That said, makers of foam mattresses now have methods to make them cooler. Some use open-cell foam, a sponge-like material comprising interconnected air pockets that allow air to circulate. “A breathable proprietary foam can actually work better than gel infusion,” says Marten Carlson, lead mattress reviewer at Mattress Clarity.

Some mattresses are infused with materials, such as gel, charcoal, or copper, that manufacturers say will aid in cooling, but the results are varied. Gel-infused foam is somewhat effective at keeping people cool, but according to the Good Housekeeping Institute’s tests, “the effect is typically temporary,” Wu says. It might feel cool when you first lie down, but over the course of the night, that sensation fades.

“While gels can help prevent overheating caused by materials such as memory foam, their actual cooling effects are typically not noticed by our consumer testers,” Wu says. “This is similar for charcoal-infused or copper-infused foams.”

Other mattresses regulate temperature with phase change materials (PCMs), which are used across industries for cooling — including in astronaut suits. The technology was developed by a company now known as Outlast Technologies, in partnership with NASA. The company doesn’t sell bedding to consumers, but you may see Outlast listed in the product descriptions of bedding companies such as Slumber Cloud. When a person’s body releases heat, the PCM absorbs the heat energy while undergoing a phase transition (such as from solid to liquid). When the body cools down, the material releases that heat again. Picture tons of tiny parcels of a substance (such as wax) that melt when they reach a certain temperature, pulling heat away from the body.

PCMs are significantly more effective at cooling than products that incorporate gel, Wu says, though they also tend to be more expensive. Generally speaking, you wouldn’t find a mattress with PCMs for less than $1,500 for a queen size, Hales says. Gel is much more commonly used, he adds, so the prices for products that incorporate it vary widely: “You’ll see gel products used in mattresses as cheap as just a few hundred dollars, and also used in mattresses that are thousands of dollars.”

With any material, quantity matters: a tiny bit of gel, for example, may not do much good, Hales says. The problem is that companies often don’t state the quantity of materials. Hales tried mattresses from Octave at different price points that all included a PCM for cooling. With the cheaper model, he couldn’t feel the effects. It was a bit more noticeable with the midpriced model, but with the priciest model, it was undeniable. In his experience, price can indicate quality differences to an extent.

“You really don’t start to see notably better cooling performance until you’re spending $1,500-$2,000 on a queen,” he says. That’s not to say a cheaper model wouldn’t still be better than one without any cooling features, but the difference may not be dramatic. Some pillows also use gel-infused foam and PCMs, so the same considerations apply.

Cooling bedding

With bedding, it’s all about the fabric. “If you are a very sweaty sleeper, you want to look for a material that absorbs a lot of moisture and will wick it away,” says Jamie Ueda, a freelance product tester.

Some breathable natural fabrics may not be labeled as “cooling” because they don’t use special technology to achieve that feel. For example, Ueda recommends linen and percale cotton (a weave with a crisp, lightweight feel). Wu agrees, adding that with cotton, a lower thread count, such as 250-300, will be more breathable than something with a higher count (though the fabric won’t be as strong, so you have to weigh your priorities). Lower thread count cotton sheets are typically more affordable, too, ranging from below $50 to around $130 on the higher end.

Then there are performance fibers, such as rayon, which feels cool to the touch, or nylon, which wicks moisture from the body, Wu says. TENCEL Lyocell (which is derived from wood) is also popular for its breathability and cool feeling. Costs for performance fabrics range widely, but many reviewers’ top choices hover around $150-$250. Wu has a cooling comforter from Rest, which uses a custom Evercool fabric made of nylon and spandex that’s designed to be extra moisture-wicking for people who experience night sweats. Some sheets and duvets also use PCM. Slumber Cloud sells a line of bedding with Outlast technology, including a lightweight comforter as well as a performance sheet set that was Good Housekeeping Institute’s top pick for cooling sheets.

Cooling gadgets

If all else fails, there’s technology that can help cool your bed. The BedJet ($599), for example, pulls air from the room and blows it directly into your bedding. There are also water-based pads such as the Chilipad Cube Bed Sleep System, which pumps water through thin tubes embedded in a mattress topper, allowing you to adjust the temperature from a remote control. You can buy one for just one side of the bed (beginning at $649) or outfit both sides for about twice the cost.

And there are smart beds and toppers, such as the Eight Sleep Pod, which uses water-based thermal elements in addition to smart sensors to regulate a person’s temperature. Reviewers say it works, but the cost is high (more than $4,000 for the newest one) and there’s a subscription fee to access all features.

Annie Midori Atherton is a writer in Seattle who covers culture, lifestyle, business and parenting.