I spent a month sleeping on a water-cooled mattress and I’d never go back

The Eight Sleep Pod Pro pumps water through the top layer to bring you to the perfect temperature and it is life changing

Eight Sleep Pod Pro
(Image credit: Eight Sleep)

Over the last month, I've discovered one of the best mattresses I've ever slept on. The first thing that drew me to the Eight Sleep Pod Pro mattress, as a gadget fan, was that it links to an app. This app gives you a nightly sleep report, from your heart rate and breathing to what time you fell asleep and the stages of sleep you went through.

The Eight Sleep app also lets you set the required temperature of the mattress, from 55 degrees up to 110 degrees Fahrenheit (12.7 to 43.3 degrees Celsius), with different values for each side. You can also set the temperatures for your different sleep stages – cool when getting into bed, a little warmer when you fall asleep, cozy in the final stages and warm to wake you up, however you choose. It will also wake you up with vibrations, like a life-size smartphone.

All of this is achieved by something Eight Sleep calls the Pod Pro. This is essentially a top cover that sits over the mattress that contains the sensors and crucially the channels of water. The Eight Sleep isn’t a waterbed. It doesn’t swish and splosh as you get into it, so it won’t leave you feeling seasick. These are tiny water pipes that contain just enough water to heat or cool the area, much like a water-cooled gaming PC, except that these can also increase the heat. And you wouldn’t know they are there, apart from the rather sizeable pipe at the back of the headboard. This attaches to the water chamber, known as the Hub, which is about the size of a desktop PC.

While you can just buy the Pod Pro cover and put it over your existing mattress, the full set comes with the Pod. This is a specially designed foam mattress with five layers of advanced foam technology to provide support, comfort and airflow. It also allows the water system to work at an optimum level.

Eight Sleep Pod Pro

(Image credit: Eight Sleep)

Eight Sleep Pod Pro Installation

The full Pod Pro set arrives in two sizeable boxes – one for the rolled mattress and the other for the cover and hub. The instructions are found in the second box with the cover and hub, but in my excitement, I went straight for the mattress. It’s not only rolled but vacuum-sealed, so once you lay it out and puncture the plastic cover it expands to its full 12-inch height in minutes – there’s no waiting for hours for the foam to expand, it’s ready to go.

With the mattress in place, you then unfold the Pod Pro cover and feed the water pipe down under your headboard to where you will place the Hub. The cover then zips into the mattress to keep it in place. Due to the length of the pipe the Hub naturally sits next to the bed, in between the bed and nightstand. It does need power as well as a strong Wi-Fi signal for the app to connect. I needed to plug in a Wi-Fi extender to ensure the signal was strong enough.

Once all connected you need to prime the water. The app takes you through the whole process with short videos. It recommends using filtered water and adding a drop of hydrogen peroxide, which you can pick up at most pharmacies (or from Amazon). The first priming takes a few minutes, while the second prime is much longer but you can start to use the bed while it does its thing.

Eight Sleep Pod Pro

(Image credit: Eight Sleep)

The Eight Sleep Pod Pro app

The best thing about the Eight Sleep Pod Pro is the app. It’s available for Android and iOS and provides all the temperature controls and sleep data. For the temperature controls, you can treat the whole bed as one temperature (for single sleepers) or divide it into two halves and invite your partner to also download the app to control their side.

It then allows you to set regular schedules for your bedtime and waking up time. You can do this for each day or groups of days, so if you want one time for weeknights and another for the weekend, you can make it happen. When setting the wake-up time you can also set the temperature to wake up to and the level of vibration, on a level of 1 to 10.

The app will suggest a sequence of temperatures based on some initial questions as to how warm you like your bed. It will normally suggest a warmer wake up temperature though. I like to get into a cool bed but then be warmer in the night, so I start on a -4 for bedtime, a -3 when I first fall asleep, a zero while in the final stage and a +5 to wake up (the scale goes from -10 to +10).

When you set a bedtime, the Pod Pro will start cooling (or heating) the bed about 30 minutes in advance, so that it’s already to temperature when you get in. This is especially nice on a hot night to get into a cool bed, and I suspect when winter hits, it will be nice to set it up to be toasty warm too.

The other use of the app is that it provides you with data on how you have slept. For those fascinated with sleep trackers, this takes things to another level, and without having to leave your watch on overnight.

Each morning you are awarded a sleep fitness score (out of 100), it then breaks that down into time slept, wake up consistency, time to fall asleep and time to leave bed. It also then gives you a timeline of when you got into bed, when you fell asleep, when you woke up and when you got out of bed. There’s even a graph of your sleep stages, tracking your deep sleep, light sleep, REM sleep and awake time.

And the data goes further. On another tab, you can see your heart rate variability, your sleeping heart rate and sleeping respiratory rate.  These are more useful compared over weeks and months but are useful to gauge your stress levels, health and restlessness.

The app also offers mediation and breathing exercises, calming sounds and even bedtime yoga exercises to wind down.  You can easily spend a lot of time reviewing your sleep patterns, or you can set it once and never use the app again – though you do need it to turn off the morning alarm and stop the sleep session. I normally find I give it a quick scan when I wake up.

Eight Sleep Pod Pro

(Image credit: Eight Sleep)

The Eight Sleep Pod Pro mattress

As already mentioned, the actual mattress is also specially designed to improve your sleep experience and features five unique layers design to support, comfort and provide airflow. At 12-inches, the Pod is standard for a foam-based premium mattress. While it doesn’t claim to be memory foam it has a 4-inch premium foam base, a 4-inch ‘FlexSpring Technology’ layer, a 1-inch ‘Supportive Air Technology’ layer, a 2-inch ‘Airflow’ top layer and then a 1-inch ‘Comfort Blend’ layer.

The result of this combination is a medium-firm mattress that works for side, stomach or back sleepers. It definitely felt firmer than my previous sprung mattress with topper, but is far more comfortable to sleep on – and I’m very much a side sleeper.

There’s also very little motion transfer here. My partner getting in or out of the bed has no effect on my side. The only area it is lacking in is edge support. Sleeping right on the edge of the bed can feel like you’re about to roll out. This is likely to be less of an issue on a king size mattress, or if sleeping alone.

The Eight Sleep Pod Pro price

With all that technology onboard, it will come as no surprise that this costs a little more than your average mattress. A queen-size Pod Pro will cost you $2,895, while the full size starts at $2,595 and the Cali King comes in at $3,295 (the same price as the king). You can also buy just the mattress from $2,095 or the new Pod Pro Max (with extra heat dissipation for hot sleepers) from $3,095. The Pod Pro cover (designed for standard mattresses) starts from $1,595.  

Unfortunately, Eight Sleep is only available in the US right now. 

Is the Eight Sleep Pod Pro worth it?

There’s no denying the Eight Sleep Pod Pro takes a little getting used to. All the settings can seem a bit overwhelming and knowing that water is pumping around underneath you might feel odd to some – not that you can feel it. But one month in, I don’t want to sleep on a bed without a Pod Pro system. The level of temperature control is truly impressive and being able to fine-tune the exact temperature you sleep at is game-changing. Sure, I could live without the vibrations waking me up in the morning, but I feel the same way about any kind of alarm clock at 6am – including my dog.

The sleep data is really interesting too, though it does penalize you for reading in bed or having a lie-in, which feels a little harsh. Looking back at my last month’s sleep fitness, my numbers haven’t improved but I definitely feel like I’m sleeping better.

If you’re a fan of sleep tracking data, or just like getting into a perfectly cool bed, the Eight Sleep Pod Pro is a must. Just prepare to be disappointed when you sleep anywhere else.