A Battle for the Ages: Self-Described “World’s Hottest Sleeper” vs. Eight Sleep Pod 3 Cover

This is the first time I, the hottest sleeper in the world, have felt too cold in bed.
By Sean Evans
March 12, 2024

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To say I enjoy sleeping cold is an understatement.

My ideal bedroom is nestled inside an ice cave somewhere within the Arctic Circle. I’d enjoy seeing my breath as I drift off. My preferred teeth-chattering temperature is seldom achieved (though, via an open window and full-blast air conditioner in the dead of winter, I once managed a morning film of ice atop my bedside water. Small victories). 

My blocker? My beloved wife. She would ask the devil for a blanket because Hell could be hotter. Save for her disdain of creepy crawlies, she’d blissfully snooze in the oppressive heat and humidity of the Amazon. 

The battle for bedroom climate control has dragged on for years. The irony that fighting over how to get better sleep is so tiresome hasn’t escaped us. 

However, we have a recent detente, thanks to Eight Sleep’s Pod 3 Cover. 

Smart, cooling mattresses and mattress covers aren’t new, but Eight Sleep has built a better mousetrap. It’s not a cheap solution—prices start at $2,195 for a Full and run up to $2,495 for a King—but who isn’t willing to shell out for something that’s unequivocally effective, particularly for improving sleep quality?  

I’ve slept on an Eight Sleep Pod 3 Cover for six months. Here’s my honest review. 

Eight Sleep Pod 3 Cover

  • Totally eliminated hot sleeping
  • Non-intrusive design
  • Functional app
  • Easy to maintain and clean
  • Paywalled features are a huge bummer
  • Requires Wi-Fi for everything

What Is the Eight Sleep Pod 3 Cover?

It’s a smart mattress topper that can modulate your bed’s temperature throughout the night—kind of like Chilisleep’s Ooler or Dock Pro

It heats or cools your bed anywhere between 55-degrees F and 110-degrees F by running cold or hot water through an embedded series of tubes (called the Active Grid) within the mattress topper.

What makes it smart, and what separates it from other similar products, is the amount of sleep and health biometrics it records via sensors in the Active Grid, and how it analyzes that data to make recommendations to settings—the latter of which requires your purchase of the app’s 8+ Pro package ($19 per month).

The cover links with an app to determine your temperature settings and programs. It has dual zones, for you and your partner, which can operate on different schedules.

For example, if you want to be in a hot bed at 10 pm, it will warm up your side of the bed starting around 9:30, while simultaneously cooling the other side for your partner for a 9pm bedtime.

The bed can also set alarms, and gently vibrate you awake in the morning.

eight sleep product covering large mattress
The Eight Sleep cover over the author’s mattress. It’s a quilted cover and if you press your hand into it you’ll feel the tubes that pump water through it.

What’s Good About the Eight Sleep Pod 3 Cover?

Totally eliminated hot sleeping

The first few nights on the Eight Sleep were a smidgen rough, mostly due to the Eight Sleep’s thermoregulation is so effective, I was…too cold.

I was unaware this was feasible.

If you’re wondering how cold the Eight Sleep can get, the official answer is 55-degrees F. The anecdotal response is absolutely freezing, which is why I woke up in the middle of the night, shivering, seeking extra blankets.

I switched from a -6 to a -2 on the app’s coolness scale and found that perfectly acceptable. I’m not sure what temperatures Eight Sleep’s numbers correspond with—your options are -10 for cooling through +10 for heating—and couldn’t find anything online, either. For those seeking warmth, my wife tried a +6 the first few evenings and found it scorching, ultimately adjusting down to a +3.

If you use a mattress cover on top of the Eight Sleep cover you can bump the temperature down (or up) more—we’ve both moved back to -6 and +6 since adding a cover between the device and our backs, respectively. It’s wild to slip into my deliciously frosty side and inch my foot over to my wife’s half of the bed to feel the warmth emanating.

Another telling efficacy fact comes courtesy of our dog, Edgar, a chihuahua-mix who sleeps in bed with us. Tipping the scales at 11 pounds, Edgar’s most zealous life pursuit is to be warm. Prior to the Eight Sleep cover, the warmest area of the bed was mine, so he’d sidle up to me early in the night, causing me to get even hotter, which, of course, led to him snuggling closer. A horrible self-perpetuating cycle where I would arise sweaty and still exhausted and he would look vibrant and refreshed. Now? He refuses to budge from my wife’s side, groaning when forcibly moved.

Can you wash the Eight Sleep Cover?

The Eight Sleep cover is not machine washable. There’s too much tech in there, so Eight Sleep recommends a proprietary thin waterproof cover (for $119), and treating stains and spills with a damp cloth and maybe some mild detergent.

However, Eight Sleep also doesn’t recommend washing the entire thing by hand. You can wipe it with a wet cloth every now and then.

Aside from that, you’ll have to change the water and recondition it with the hydrogen peroxide every few months to prevent bacteria from cultivating. It’s not terribly time-consuming.

Tracking data from Oura Ring
A day’s worth of sleep (left) and Readiness scores I recorded. There is more detailed information of each of these data points a short scroll down, but I find the summary sections provide more than enough for my lizard brain to take in.

Functional sleep monitoring app

The app is easy to navigate and establishing your profile and sleeping cohort is simple. Answer basic questions about blanket coverage, preferred temperature, your age, and Eight Sleep correlates your inputs against its base of users.

My cohort is males in their 40s who prefer to sleep cold. The helpful insights come from a temperature recommendation culled from those fellow guys, which lists -6 as the preferred bedtime temperature, then gently warms to -2 for REM sleep, before chilling again for wakeup. 

As noted, you’re free to adjust the individual phases or tweak your temps on the fly, so what you start with isn’t etched in stone.

Non-intrusive design

I’m an annoyingly light sleeper, who employs an eye mask and ear plugs, and complains when the softest of sounds bleed through said ear foam. I also get irked at the sound of another human chewing, just to illustrate how attuned to auditory nuisances I am.

While the device produces some noise—a low hum, technically—as the Hub conditions the water then pumps it into the Active Grid, I would characterize it as supremely faint in the quiet of the spring and fall, and imperceptible in the summer, over the din of the air conditioner. It certainly didn’t encumber slumber for my wife nor me.

Because there’s water flowing beneath, I felt some vibrations as the cover did its thing. The potency of the sensation was on par with a phone vibrating from under two or three mattresses. My wife did notice this, too, early in our Eight Sleep trial. Acclimation is fast though, and as with the noise, it’s nothing rousing you from nor preventing you from sleep.

The Pod 3 Cover’s fit, finish, and overall aesthetic is my vibe: clean, simple, modern. It’s dark gray, the hue my wife’s beautiful white percale sheets turn before she glowers at me while chucking them in the trash. So I’m loving that gray color from the jump. The fabric feels sturdy, like it won’t shred after a year’s worth of my tossing and turning my 200-pound frame. (The unit comes with a two-year warranty, if you’re curious.) 

The hub’s modern design meshes with any decor yet it doesn’t stand out. It also happens to nest below my bedside table, tucked away from view, since its footprint is too sizable to occupy the limited space between the bed and the wall. 

What’s Not Good About the Eight Sleep Pod 3 Cover?

Paywalled features are a huge bummer

Eight Sleep tracks your sleep via sensors built into the unit. The point is to capture all the data, including tosses and turns, sleep stages (REM versus light sleep), bed and wake up times, time to fall asleep, wake up consistency, time slept, heart rate, heart rate variability, sleeping respiratory rate, and more.

An algorithm combines a bunch of these metrics to get your Eight Sleep fitness score, out of 100. Atop the biometrics the bed tracks, you’re encouraged to self-report sleep-relevant facets of your life via a tagging system in the app.

The overlay of the biometrics and habits and emotions is meant to combine for a more complete data-driven snapshot of your slumber, from which derived insights generate recommendations.

But the most robust analysis and suggestions are nestled behind a $19-per-month Pro version. As are guided meditations and other exercises and tools meant to dovetail with those recommendations, a concerted bid to improve your sleep quality.

While alluring, I didn’t employ this feature. Frankly, paywalling utilities like deep data analysis and behavioral tools feels like a miss given the high price of the unit; it should be complimentary. As should Autopilot, a service to “train your own microclimate algorithm,” per the app. This takes all your data and subsequent learnings to continuously adjust your bed during the night.

There’s also the question of data validity: how accurate can a mattress cover or bed truly be at determining your heart and respiratory rate? According to Eight Sleep, which employs a slew of medical doctors and PhDs, the Pod’s sleeping heart rate tracking is 99 percent accurate. It’s a bold claim that the company is currently attempting to prove in partnership with a clinical trial with the Icahn School of Medicine at Mount Sinai.

Requires Wi-Fi for all functions

The Eight Sleep units require wifi to function. You can’t control the bed or gather any sleep data without wifi, sadly. That’s a big “sadly” for two principal reasons. 

First, it’s at odds with those heavily investing in sleep betterment, especially those concerned about the potentially negative effects of electromagnetic fields (EMF) on sleep. Research is mixed on the topic, with some studies claiming things like wifi, Bluetooth, and other devices that emit EMFs negatively affect the quality of your sleep; other clinical findings draw no such conclusion. While we wait for the science to align, if you’re seeking an EMF-free bedroom, the Eight Sleep Pod 3 Cover isn’t for you. 

Second, there’s no way to use temperature control of the bed without using wifi and the app. Meaning at 2 a.m., when you need to adjust the cover a few degrees, you need to fumble for your phone, brace your eyes, then squint through bright lighting while you navigate and tap away. It’s a harsh, less-than-thoughtful experience for a product designed to improve sleep.

More Sleep, Please

The Experience

Set aside time for setup

Setup is largely easy, though it does take a total of 3 or so hours, much of which is the system conditioning itself. The Eight Sleep app recommends having two people available for set up, but you can do it solo, though you will definitely grunt and swear. 

There’s a fun welcome note that mentions sleep fitness, a novel concept behind which Eight Sleep’s trying to build momentum. Beside the note, a QR code to snap to launch the Eight Sleep app and you’re away. 

First, the encasement (what the Active Grid attaches to) must be secured to your mattress. To ensure adequate encasing, the brand’s logo is a marker for positioning, and that’s bolstered by short GIFs that accompany step-by-step instructions in the app.

In theory, this physical application is simple. In practice, it’s a solid struggle. It’s going on top of my 15-inch thick Avocado Plush Organic Luxury Mattress, and then a Tempur-Pedic Adapt+Cooling topper. (I like supremely plush bedding. What of it?) The encasement goes on like a fitted sheet, so if you huff and puff when making the bed, you’ll be wheezing at the end of this exercise.

The heart of the Pod 3 Cover is the Active Grid. Think of this like a mattress topper with embedded thin tubes to house the water that thermoregulates you. 

The Active Grid is in a vacuum-sealed bag, though it plumps up pleasantly upon air exposure.

There’s a sticker that says top left corner and a thick tubular tail that looks like an umbilical cord, the artery of the sleep fitness machine. (It’s how the water gets from the Hub into the Active Grid.) Once it’s laid out, the Active Grid gets zipped to the encasement cover then it’s time for final tightening.

Cinching the straps tight to secure the whole shebang to the bed, I feel like a trucker strapping down a load. And there’s no shortage of reminders that you need all your strength. 

Finally, we arrive at The Hub, which is the brain of the system. It looks like a desktop computer console, and it’s sleek enough and has rounded soft edges and a nice felt front cover, as well as a pleasing blue LED glow emitted from the base. 

Priming the hub involves pouring water mixed with hydrogen peroxide—a few tablespoons, to keep the water bacteria-free—into a cylindrical vessel. You’re finally done with setup. It’s easy enough, but it takes time.

eight sleep pod hub sitting on a wooden floor
The Hub is pretty sleek, all things considered. It looks nice enough to leave in view, but is small enough to slip under a bedside table.

Sleeping on the Eight Sleep

For those looking for a sensory description of the Eight Sleep Pod cover, I’d best liken it to sleeping on a very comfy air hockey table. Or what I imagine that setup would be like, at least. 

The Eight Sleep cover’s ability to freeze or nuke you is potent, so you’re getting a radiating sense of cool or hot from the sheets themselves. And it’s continual, similar to when you pass your hand over an air hockey table and feel that sensation of air. Adjust a limb during the night, and you’ll find it pushing through a cold or warm front, essentially. 

Honestly, I found the first few nights less than fully comfortable due to feeling the tubes. I’ll stop short of saying they were uncomfortable, but again, I’m the princess angered by the pea beneath my yards of dense memory foam. I pinged the Eight Sleep rep who recommended a mattress cover, specifically this $25 one from Utopia Bedding

That mattress cover solved my issues—I no longer feel the Active Grid tubes, nor hear noise from the Grid during rustling—and it’s since been blissful. With the mattress topper in place, I’d give the Eight Sleep Pod 3 Cover good marks for comfortability. I’ll add that I’m a back and side sleeper, so I’m not sure how stomach folks would fare.

Inconsistent (but interesting) sleep data

I don’t wear any trackers to bed, so I can’t cross-examine data streams to determine accuracy, but laser-accurate sleep data also is not a thing that matters a ton to me. Anecdotally, I can share that it seems to be getting plenty of metrics correct. 

Case in point: Eight Sleep knows when I’ve been drinking alcohol. Each morning after an impassioned run at the bar, I get an alert from the app: Feeling less energized? Your sleeping heart rate was 37% higher than usual last night.

It’s frustrating that my bed knows if I hit the sauce too hard, worsened by my guilt that interprets this benign query as a passive-aggressive accusation. But it’s also impressively accurate. It happens, without fail, any time I’ve consumed more than two alcoholic beverages. 

Conversely, it has, on several instances, recorded data on my side of the bed when I’m traveling. Or completely duffed my bed and wake times. I do wonder how sensitive the sensors are and if the presence of the dog is throwing any metrics off. I’m also curious if my data is affected when, say, my wife’s arm or leg encroaches on my side of the bed. 

I’d say the reported data is OK, but one of the largest detractors here is that the limited data from the app rarely jives with how I feel the following morning.

I can wake up, feeling super refreshed, knowing I fell asleep quickly, and feeling like I got solid sleep, only to get served a sleep fitness score of 46. 

But if my biggest complaint is that the bed’s app doesn’t quantitatively show that I feel as great as I do, is that really a serious problem? Nope.

Did it work?

There are some impressive marketing numbers surrounding Eight Sleep. The technology “can increase deep sleep by up to 34 percent, increase heart rate variability by up to 19 percent, and improve sleep quality index by up to 32 percent,” per a company press release. 

I improved my sleeping heart rate by about 15 percent though my deep sleep remained steady (~25 percent). But I’d say my sleep quality index has improved by about 50 percent. 

I fall asleep faster. I sleep longer, with fewer tosses and turns. I haven’t once woken up with a single bead of sweat. I wake up happier, which means I’m starting my day feeling better. All of this leads me to appreciate my sleep and my bed more.

The Bottom Line: You Should Buy It

Let’s tackle the elephant in the boudoir. Given how much Eight Sleep Pro Pod Covers cost—$2,145 for a Full, $2,245 for a Queen, $2,445 for a King or a Cali King—you’re wondering “is the Sleep Pod worth it?” Fair question. Yep, Eight Sleep is definitely worth the high cost.

Eight Sleep has eradicated my sleep-related malaise, transforming a dreadful nightly requisite to an enjoyable one.