Some people will tell you that the secret to a happy relationship is communication. Others will tell you that it’s affection, or intimacy, or being able to admit when you’re wrong. For my partner and I, though, the key to success is an Eight Sleep mattress.

As a hot sleeper who fell in love with a cold sleeper, I genuinely believe that our relationship would not have survived without an Eight Sleep. Early on in our relationship, he jokingly told people that my temperature-controlled mattress was the best thing about me. Four years later—and nine months out from our wedding—we got our hands on the latest iteration of the mattress—the Eight Sleep Pod 4 (normally $2,549, now $2,399)—and I now feel even more confident that there’s a lifetime of happiness ahead.

What is the Eight Sleep?

The Eight Sleep is a product unlike anything else on the market, and I don’t say that lightly. It’s a mattress cover that does *so much*—in addition to allowing you to set your ideal sleep temperature, it also tracks your sleep patterns, changes temperatures to optimize your sleep, and can even function as an alarm.

The cover zips onto any standard mattress and connects to an external hub that pipes cool and warm water into the cover, which fluctuates between 55°F and 110°F. You can manually adjust the temp via an app on your phone, and the bed is split down the middle so that if you’re sharing with a partner you can both drift off to dreamland comfortably.

While you’re sleeping, the cover tracks metrics including heart rate, HRV, sleep stages, and respiratory rate, all of which go into that same app on your phone. As it gets to know your patterns over time, you can set it to automatically adjust to maximize your sleep. This “Autopilot” program takes a slew of different factors into consideration, including biometrics (your age and sex), your sleep patterns (how much time you spend in light sleep versus REM sleep versus deep sleep, how long it takes you to fall asleep and get out of bed), your sleep preferences, and your environmental temperature, and uses a complex algorithm to determine your optimal settings.

This is critical because your body temperature changes throughout the night, and per the brand, “80 percent of Americans suffer from temperature issues during sleep.” I, for example, like a frigid mattress when I go to bed, but won’t sleep as well and will wake up shivering at 2 a.m. if it stays that cold all night—my Eight Sleep now knows that (freaky, but cool!), and adjusts itself accordingly.

Another favorite feature of mine is the routines you can program within the app. My mattress starts to cool down at 10:30 p.m.—around the time I go to bed each night—and then heats up to an uncomfortably balmy temperature at 7 a.m. to get me out of bed in the morning. In addition to the thermal alarm, there’s also a vibrating alarm that gently shakes the whole mattress, and is a whole lot nicer to wake up to than the screech of an iPhone.

What’s new with the Eight Sleep Pod 4

Eight Sleep Pod 4 — $2,399.00

Normally $2,549

What it includes: A mattress topper, an Eight Sleep Pod

Pros: 

• Dual temperature control
• Vibration and thermal alarms
• Sleep and health reports via app
• Snore detection

Cons: 

• Expensive

When Eight Sleep launched in 2019, I had the chance to test out the first-generation version of its product, and haven’t been the same since. Five years and three new iterations later, the fourth-generation Pod has gotten some *major* upgrades.

For starters, it’s a lot more comfortable. The original version of the Eight Sleep was a bit firm for my liking (and you could kind of feel the pipes inside of it when you laid at certain angles), but I loved its technology so much I didn’t mind sucking it up. This new cover is *so soft,* that the first night my fiancé and I got into it, we said, “Holy crap, this bed is amazing,” to each other at least 15 times.

That sentiment continued as we began to play around with all the new features. The new cover heats up and cools down a whole lot faster and more intensely than the original, transforming my side of the bed into an icy tundra and my partner’s into a tropical oasis in a matter of seconds. The tracking features are also even more accurate than what we were previously working with (they scored 99 percent accuracy when tested against gold-standard products, and I can confirm it to be true after comparing the metrics with my Oura Ring’s), and now keep tabs on your snoring in addition to all the other metrics.

While the old version of the Eight Sleep relied on the app for manual adjustments, the Pod 4 allows you to control the temperature and alarm features on the device itself—a major win for anyone who wants to sleep with their phone outside the bedroom. Two taps on the side of the Pod will cool the cover down, three taps will heat it up, and two taps will snooze the alarm.

The Eight Sleep Pod 4 Ultra Upgrade

Eight Sleep Pod 4 Ultra — $3,849.00

Normally $4,049

What it includes: A mattress topper, an Eight Sleep Pod, an adjustable base

Pros: 

• Dual temperature control
• Vibration and thermal alarms
• Sleep and health reports via app
• Snore detection and mitigation
• Custom elevation

Cons: 

• Expensive

As if all of that wasn’t enough, there’s an even more premium version of the Eight Sleep called the Pod 4 Ultra (normally $4,049, now $3,849), which is what we’re currently (blissfully) sleeping on.

It has all the same stuff as the basic Pod 4 (which, let’s be honest, isn’t basic at all), but also comes with an adjustable base that—wait for it—allows you to change the position of the bed. Instead of stacking up pillows to read before bed, the mattress will prop you up seamlessly and comfortably. I’m currently writing this on a laptop from my bed (something I do every day, despite every expert I’ve ever spoken to telling me not to), and my back feels supported and pain-free.

You can control the elevation via your phone or by tapping the side of the Pod, but you can also set the mattress to adjust while you sleep. When the Pod senses you snoring, it will automatically raise your head to stop it. If you’ve got a partner who keeps you up at night with their nose noises, do yourself a favor and get your hands on one of these babies, STAT.

Final thoughts

For years, I’ve joked that I’ve been doing Eight Sleep’s PR because I’ve convinced *so* many people to invest in this truly life-changing technology (including friends, strangers, and literal celebrities). Its temperature-control abilities, on their own, are enough to make it worth the admittedly steep price point, but over time, I’ve fallen in love with the sleep-tracking features, too. I love that on days when I’m feeling low energy, the app validates that it really *is* because I’m exhausted, and it’s cool to see how different factors (like drinking wine or working out before bed) affect the quality of my sleep. And now that I can sit in my bed all day without back pain, I might never get out of it.

While there are plenty of other reasons my fiancé and I decided to get married, the fact that we don’t have to fight about the temperature of our bedroom has us well on our way to wedded bliss.