Slumber Cloud Cooling Mattress Pad Review

slumbercloud cooling mattress pad


The SlumberCloud mattress pad is an effective cooling mattress pad that can help you sleep more comfortably. Whether you’re a hot sleeper, suffer from night sweats or hot flashes, it will help dissipate the heat your body creates in bed.

It also helps to mitigate the buildup of heat that can happen with a memory foam mattress or topper. I’ve used it throughout the summer months for the last two years now, and have been happy with how it compares to standard bedding.

Good points

  • Helps keep your body cooler in bed.
  • Works throughout the night.
  • High-quality materials, with a robust design.
  • The elastic skirting fits all mattresses up to 20 inches deep.
  • Fits on top of a mattress or mattress topper.
  • Hypoallergenic and machine washable (in cold water).
  • 60 day no questions asked satisfaction guarantee.


  • It doesn’t add much additional padding.
  • It won’t change the temperature of your bedroom, but does dissipate heat from underneath you.

If your total purchase is $150 or more, you can get a $15 discount using my promo code GOODNIGHT.

Full review

In the photo below, you can see my mattress pad ready to fit on the existing mattress:

the slumbercloud comforter on my bed

The Slumber Cloud nacreous mattress pad promises to help keep you cool in bed by dispersing your body heat from underneath you.

It uses fabrics containing Outlast Technology, which is a cooling method originally developed for NASA. So with a claim to fame like that, I was expecting great things.

I tend to quickly overheat in bed, and my experience is that bed cooling isn’t so easy to achieve – especially in a hot bedroom with no air conditioning in the summer.

I’ve used several cooling mattress pads and bed fans in recent years, and I’ve come to a simple conclusion: there’s no perfect solution to bed cooling, but your choice of bedding can definitely make a difference.

So I decided to give the Slumber Cloud nacreous mattress pad and pillow covers a good test this summer.

Construction and materials

slumbercloud mattress pad in the original bag

Out of the packaging, it’s immediately obvious that the mattress pad is well made. It has a soft feel to the touch, but also looks like it will last the test of time.

The outer cover is a quality 300 thread count, made from 40% Outlast viscose and 60% cotton.

The inner lining consists of 100% polyester fiberfill and the Outlast material. That adds some fill to the pad – probably about an inch of loft in total.

I liked that it has a very deep stretchy skirting, with a strong elastic band to keep it in place. The skirting will fit a mattress up to 20 inches deep. My mattress is less than that, and I found the elastic was tight enough to keep it tightly in place on my bed.

Below: The Slumber Cloud mattress pad set up on our bed. It comes with a wide skirting so you can attach it to a thick mattress.

the slumber cloud mattress pad set up on my bed

How does the cooling work?

The way the Slumber Cloud pad actually keeps you cool can be a little confusing. The simple answer is that it’s all about some little beads called ‘thermocules’ which are in the Outlast material.

As your skin temperature increases, those thermocules absorb your excess heat and store it away from you. And if your body temperature drops enough in the night, they return some of the warmth to keep you comfortable.

To find out more about how this works, I got in touch with Slumber Cloud. Here’s what they told me:

Thermocules™ is the trademarked name for the housing of the technology. These are essentially microscopic beads comprised of a “shell” that will change states (from a solid to more of a gel) when the temperature changes.

As your skin temperature increases, the technology will absorb that excess heat to reduce overheating. The technology will then store the excess heat away from your body until your skin temperature begins to drop. When this occurs, the stored heat is released back to you to keep you at the perfect temperature.

More about Outlast technology

To understand better how it works, I decided to see what the makers of the Outlast technology part have to say about the way the thermocules work.

They explain that the technology was originally developed for NASA, and add the following:

Outlast® technology, originally developed for NASA, utilizes phase change materials (PCM) that absorb, store and release heat for optimal thermal comfort. Outlast® technology is comparable to ice in a drink; as it changes from solid to liquid, it absorbs heat and cools the drink, keeping that drink at the desired temperature for longer.

So there you have it: you are the drink that slowly gets too warm, and the mattress pad is the ice cube that helps keep you cool. And the best bit is that it’s an everlasting ice cube that returns when you cool down or move to a different part of the pad!

My experience using the mattress pad

The Slumber Cloud pad arrived nicely packaged in a plastic carry case, which is good for future transportation.

The pad looks smart, which I liked, with enough box panels to prevent the inner lining from bunching. It was very easy to fit, with the skirting and elastic band holding it strongly in place on my bed. I put a cotton sheet over the top too, wanting to see if it works through a sheet (it did).

That first night, I definitely noticed that it felt a little cooler to lie on than just the mattress. It also added a thin layer of plush padding, which felt comfortable under my body without altering the firmness much.

I woke a couple of times in the night as usual and noticed that I didn’t feel too hot, which was great. But it wasn’t a particularly hot night, so a bigger test would come later.

Over the next couple of weeks, there were a few sweltering summer nights, so the pad got a thorough testing.

What I found was that it stopped me from feeling uncomfortable where my body was in contact with the bed. I don’t think it cooled my entire body as such, and I still felt a bit warm on some of the hottest nights.

But it was great not to wake up feeling like there was sweat between me and the bed! And that cooler period at the start of the night made it easier for me to tolerate the heat and fall asleep easier.

It also made a pleasant change not to be constantly moving around in the hunt for a cooler spot. So all in all, I was happy with the difference it made.

The pillow covers

slumber cloud pillow covers

I also decided to get a pillow cover set to see if they would add some extra cooling effect.

They contain the same Outlast material, and I found them very comfortable to use in hot weather. So much so that when on holiday recently, I packed one in my suitcase!

I like that they are very well constructed, just like the mattress pad. Being hypoallergenic and having a solid zip, they are perfect for my dust mite allergy.

They feel lovely and soft, with a 350 thread count outer cover. And the Outlast fabric on both sides of the pillow cover helps keep your head a little cooler in the night.

I really noticed the difference with the pillow covers, as that extra cooling seemed to go a long way in helping me feel comfortable.

Cleaning and maintenance

Considering all the mention of ‘technology’, the SlumberCloud pad is actually very easy to clean. You can wash it in cold water, tumble dry on a low heat and then hang to dry.


On the whole, I liked the Slumber Cloud nacreous mattress pad (and pillow covers) enough to decide to keep using them throughout the summer.

As I half expected, it didn’t keep me completely cool on the hottest of nights. But it definitely helped and made a significant difference on some nights.

I think it’s important to understand that if your bedroom is unbearably hot, no cooling mattress pad will change the fact that the air temperature is unpleasantly high.

What it can do is help you remain comfortable by absorbing some of the heat your own body is producing. And for me, this mattress pad did a better job of that than previous cooling pads I’ve tried.

Importantly, it was better than sleeping on a normal mattress or mattress topper. So I think with a no questions asked 30-day money back guarantee, it’s worth giving it a go if you’re suffering from overheating and feel that a change in your bedding would help.

Update: trying the SlumberCloud comforter, mattress protector and sheet set

Two years after first writing this review, I still use the mattress pad at home in hot weather. Combined with a bed fan, I’ve been happy enough to keep using it as my warm weather bedding.

So this summer, I decided to try out the other bedding pieces they make – the dryline mattress protector, comforter and duvet cover, and sheets.

Dryline mattress protector

The mattress protector is also made with the Outlast technology – the norm with all of SlumberCloud’s products.

It’s 100% waterproof, so if you have a problem with sweats at night, it’s a good way to protect your mattress. I tested it with some water spillage, and it held up well.

It’s kind of hard to tell really, but I felt that the additional layer of the same cooling system perhaps also helped with the cooling under the mattress pad.

The comforter

The comforter in some ways turned out to be my favorite item – even more so than the mattress pad at times.

It feels beautifully soft and is incredibly lightweight. I found I could use it in warmer weather (though not the hottest) when there was no way I could use a normal comforter.

It’s always nice to have a layer on top of you, so the fact that this one lets you have that comforting layer a little longer into the warmer months of the year was something I appreciated.

The stratus cooling sheet

Combining premium cotton and that outlast part again, the sheets feel great. I don’t think they do much to actively cool you, but compared to many other sheets, they just feel so light and soft.

I was able to use a top sheet all throughout the steamy New York summer of 2019, which was a pleasant change from trying to sleep with no covers at all.

Which parts of the Slumber Cloud set are best?

This is a difficult question to answer! I think the most important item is the mattress pad, as that’s the one that will help reduce heat under your body. Following that, the pillowcases will also help dissipate heat under your head.

Then I’d probably go with either the comforter or a top sheet if you’d like to sleep with a lightweight cover over you.

Finally, if you want the whole system, the dryfit mattress protector. Though in some circumstances, you might benefit from that before the comforter or sheet.

If you spend $150 or more on their cooling bedding, you can get a $15 discount using my promo code GOODNIGHT.

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