Eight Sleep Pod 4 review: This smart mattress topper kept me cool on the hottest night of the year

Telegraph

18 hours ago

What is the Eight Sleep Pod 4?
There are lots of smart beds, cooling mattresses and sleep trackers, but the Eight Sleep Pod combines these features into one system comprising a temperature-regulating mattress cover, a hub and an app.
The cover looks like a standard mattress topper but hides a grid of thin water channels. These connect to the central hub which, placed by your bed, heats or cools the water between 12C to 43C to help create an environment for a good night's sleep. Sensors in the cover monitor your body and room temperature and adjusts itself accordingly. Each side can be set to suit different preferences.
In the app, you can control the temperature, set an alarm and track your sleep and health data. You can also change the temperature screen-free by tapping the side of the bed.
There are three different models. The Pod 4 reviewed here is the original model starting at £2,249 for a double. The highest spec version, the Pod 5 Ultra, retails at £4,449, but is sometimes discounted at £200 off.
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How we test cooling sleep tech
While testing eight cooling mattresses, I came across the Eight Sleep Pod 4, which presented a cooling option like nothing else I've seen on the market. With the ability to precisely change your bed temperature when needed, it's a far cry from your standard cooling mattress.
I placed a king size version of this smart mattress topper on my Simba Hybrid Ultra mattress that I share with my partner, with the hub alongside the bed. I was keen to see how easy it was to set up and use.
I tried it on both hot and cool nights to assess its comfort and effectiveness at improving my sleep by getting my body to the optimum temperature. I was also curious to see the relevance of the sleep data provided in the app.
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Set up
Score: 8/10
Firstly, I downloaded the Eight Sleep app on my smartphone and linked the system over Wi-Fi. I encountered none of the usual glitches involved with linking smart devices, highlighting the attention to detail Eight Sleep put into this premium mattress topper. Then, I followed the app's step-by-step guide for setting up the mattress cover and electrical hub, where the water tank is located.
The king size cover fits a mattress up to 40cm thick – just enough to fit my 34cm-deep Simba Hybrid Ultra (just check compatibility – the Pod may damage memory foam mattresses over time). Putting it on was much like making the bed with a mattress protector. My mattress fits snugly on the frame so there was just enough room to fit the cover down the sides; you need space to fit it properly, ensuring the water tube at the top (the one that connects to the hub) lies flat and free from any twists and turns.
Just like connecting to the app, the setup was smooth, meaning I could quickly start filling the water channels ready for my first night's sleep.
Tech features and app
Score: 9/10
The app has a yearly subscription service starting from £199. Embedded sensors in the cover send sleep analytics straight to it, so you can track your sleep stages, movement, heart, respiratory rates and even snoring.
The data was interesting as it showed how much I woke at night. Obsessing over sleep data isn't for me though, so I wouldn't assess it regularly. The best thing about the app is how easy it is to adjust the mattress temperature, especially when I set it to a breezy minus five on one of the hottest nights in June (it's adjusted by levels rather than degrees). I also programmed a wake up alarm on my side of the bed, so as to not disturb my partner and the cover vibrated at a set time each morning. This was a novelty, until tapping the bed to turn it off became annoying.
You can control the basics without your smartphone. By tapping the cover side, you can adjust the temperature up and down. But this was frustrating to work out; there's no indication on the hub or cover of what temperature is being set.
Score: 9/10
Without a cooling pillow or a cooling blanket to hand, I was keen to see how well the Eight Sleep Pod 4 performed on a balmy summer night. I tested it throughout early June, including on June 13th, one of the hottest days of the year so far according to The Met Office. It kept me comfortably cool while sleeping.
The mattress cover's black fabric feels padded due to the water channels inside. But this is soft and tactile underhand, and nice to lie on even without a sheet.
When the temperature of the mattress cooled, I was more aware of the thin water channels inside the bed and found myself thinking it was a little odd to sleep on. On the nights that I wanted a warmer feel, I noticed it less. Overall, however, it's hard to tell that there's any piping within the cover.
As soon as I told the app information about my size and sleeping preferences, Autopilot (the name of its AI tech) has been getting to know my sleep patterns and automatically adjusting the mattress temperature to improve my sleep.
Every morning it gave me my sleep score, charting how much time I spent awake or in light, deep or REM sleep. It highlighted how much I had – or hadn't – snored and monitored when I went to bed too, making me feel a little ashamed about staying up too late. My sleep score is still hit and miss, so I wouldn't say the pod has had a noticeable effect on my nights. But being able to control my bed to suit the weather has felt empowering.
One downside is that the hub can get a little noisy when at its highest cooling mode, much like a fan blowing at a low-level. This could be annoying if you need complete silence to sleep.
Value for money and quality
Score: 8/10
The Pod 4 currently costs £2,249 for a double. This is Eight Sleep's entry level design that comes with a cover, hub and subscription to the app's Autopilot plan for one year. After that expires, the subscription starts at £199 per year.
The brand has also launched an updated version, the Pod 5 Core with similar features but newer tech and a price of £2,449. And if you have a bigger budget to play with, you can invest in the Pod 5 Ultra for £4,449. It's only available as a Super King or Emperor and comes with all the features of Pod 5 Core, surround sound and a base which makes your bed adjustable and is designed to limit back pressure and even snoring.
With its luxury cover and high-tech hub and app, it's easy to see why this cooling and warming solution comes with a premium price tag. While it's an interesting and effective concept, I think you need to be fascinated with its sleep and health metrics to get the full benefits.
Technical specifications
The Eight Sleep Pod is singular in its offering, but since the 4's launch, the brand has brought out a more advanced model and version with its own base. Here's how the three stack up.
Should you buy the Eight Sleep Pod 4?
There's a lot to like about the way the Eight Sleep Pod 4 conveniently heats or cools your mattress. Its instant cooling is a welcome relief on hot nights, while its cushioned design warms your body when temperatures drop. Its app is informative too, especially if you want to monitor sleep metrics without a wearable tracker. But its hub is bulky and you need space to set it up properly, so measuring your room before you buy is key. The hefty price tag is also hard to ignore.
Yes, if:
You like the idea of a gadget that warms you in the winter and cools you in the summer
You're a hot sleeper, and have exhausted all other routes for instant cooling at night
You love analysing your sleep data
No, if:
You're on a budget; it has a high initial outlay and a yearly app subscription fee
You have a small bedroom
You have a memory foam mattress as using electric blankets or a heated topper can cause damage over time
Eight Sleep Pod 4 FAQs
Does Eight Sleep use a lot of electricity?
You will need to plug the hub in to make use of the mattress cooling and heating capabilities. I measured it at costing around seven pence per hour on the highest setting based on costs at the time of testing.
What are the sleep tracking capabilities of the Eight Sleep Pod 4?
The cover comes with built-in sensors that track sleep data each night and gives you a 'sleep score' between one and 100. It charts awake time at night, deep, light and REM sleep, snoring, and heart and respiratory rates.
How does the Eight Sleep Pod 4 work?
The Eight Sleep Pod 4 uses water-based thermal technology, biometric sensors and AI-powered software to track your sleep and make temperature adjustments.
How easy is the Eight Sleep Pod 4 to set up on a bed?
The Eight Sleep Pod 4 cover comes in four sizes and is designed to sit snugly over your existing mattress. This is easy to set up and links to an electrical hub that sits alongside the bed. Set up is straightforward as the Eight Sleep app will guide you through the process step by step.
How does the Eight Sleep Pod 4's temperature regulation work?
The cover has thin water channels running through it and links to a hub that sits alongside the bed and circulates water through the channels to heat or cool the mattress surface.
Is there a subscription required to use all the features of the Eight Sleep Pod 4?
Yes there is an Autopilot subscription required to use all of the Eight Sleep Pod 4 features. The starting cost is £199 per year.