8/10
Open rating explainerInformationWIREDSubstantial cushioning for pressure points. Prevents movement that would make the bed shake. Insightful sleep tracking and firmness tailoring.TIREDEven at its firmest setting, it won't perform like a truly firm hybrid mattress. Foam makes it run warm.Firm mattresses are often considered the gold standard for improved spinal alignment, even weight distribution, and overall support. As a certified sleep science and brain health coach, I’ve been on this particular soapbox for a long time.
I’m one of several WIRED reviewers who deal with back pain and who champion the benefits of a firm mattress. However, one of Sleep Number’s newest offerings, the ComfortNext Lux, has changed the way I look at softer beds.
The Reboot
Photograph: Julia ForbesThere have been many changes at Sleep Number lately, starting with the reorganization of its offerings into three collections: ComfortMode, ComfortNext, and Climate. Within these collections are five new mattresses, with the ComfortNext Lux as the mid-tier newbie from the ComfortNext line.
The premise of this new line is upgrading pressure relief, cooling, and general support. You’ll still get the hallmark features of a Sleep Number bed, which include intensive sleep tracking from the bed itself, and 100 firmness levels at your fingertips via app connectivity. You’ll also have a range of motion for the bed's top and bottom, along with settings like zero gravity to reduce pressure on the spine, provided you have an adjustable base—more on that in a minute.
Squish Factor
With smart beds, the ability to adjust firmness levels depends on an internal air chamber. It inflates to become firmer or deflates to become softer. Many smart beds will incorporate a few thinner layers of foam to be a buffer between you and the air chamber. That is still the case with the ComfortNext Lux, but the softness is quite prominent due to a thicker layer of foam on top. There is an easy 3 to 4 inches of sinking to be had here, depending on your build. I was also surprised to discover this bed uses micro coils, something I’ve never seen in any smart bed from any brand.
In my over six years of mattress testing, I haven't found micro coils to be a life-altering mattress material. They simply add structure to a mattress, especially one with three or more layers of foam. To this end, they provide better support across the surface, so you don’t sink through all these layers. Usually, I can’t detect micro coils, but with the ComfortLux’s softer surface, they made all the difference in maintaining full-body support. Without them, this mattress would have been an absolute marshmallow.
Photograph: Julia ForbesLike any Sleep Number smart bed, the ComfortNext Lux offers 100 firmness levels, and the one you select is your “Sleep Number,” or the firmness you prefer to sleep on. I usually skew toward firmer for lumbar support and weight distribution, which has previously been in the 40 to 50 range. Then, a new recommendation popped up in the app—my firmness level was in the mid-70s, but going softer could improve my sleep score, which Sleep Number calls its “SleepIQ score” and reports in its app. I decided to lower it to a much softer firmness level of 35.
The SleepIQ score summarizes your nightly sleep metrics, including heart rate variability, breathing rate, and time spent in each sleep stage. This data is compiled into a score that summarizes your sleep quality. The app’s score always skewed lower than what my Apple Watch SE would track. However, with dogs jumping in and out of bed, the sensors track that motion and take it into account, too. Despite this, my Apple Watch showed a six-day streak of high-80s to 90s sleep scores. Given that my body is always getting used to new beds with a revolving door of mattresses to test, this is extremely rare for me. Previously, while testing other smart beds or standard mattress types like memory foam or hybrid, I'd achieve this kind of quality sleep with medium-firm or true firm mattresses, never soft ones.
What was clear after two weeks of testing was that, even at the absolute firmest 100 setting, the ComfortNext Lux still felt only medium-firm. I started off with firm and went way softer, but the reality is that the ComfortNext Lux’s plush foam layers will always make whatever level you choose feel softer. If you are seeking a truly firm mattress—like one of our favorite firm options, the Plank Firm Luxe—the ComfortNext Lux does not even remotely play in the same league. This is not shocking, as nearly all smart beds I've tried lack the rigidity you’d find in coil-based designs.
Got Your Back
If you regularly deal with back pain or have more severe spinal conditions such as scoliosis, I don’t recommend this smart bed for you. My husband is part of this club, and according to him, the ComfortNext Lux is doable for a few days. After a bit, he needs to return to a firmer mattress to get the support his spine needs. To this end, the ComfortNext Lux's lumbar support is not where it needs to be for full-time stomach sleeping or heavier-bodied sleepers who require lift around their midsections. Some adjustable bases will have lumbar support bars that project from the base, which would be a beneficial remedy here. Unfortunately, this feature isn’t available on Sleep Number bases at this time, and I don't recommend pairing this smart bed with an adjustable base from another brand.
If not for back pain, you may wonder who the ComfortNext Lux works best for. In short? Side sleepers. As a side sleeper myself, this mattress offers the level of cushioning I often crave for my pressure points, with a satisfying amount of sink-in that makes the joints feel cushioned. You truly feel cocooned, and not in a claustrophobic way. For couples who happen to be side or side-back sleepers, the foam's prominence in the ComfortNext Lux also helped prevent motion from rocking the bed. However, it is a bit harder to move between sleeping positions because you are working against the softer surface as you roll.
Photograph: Julia ForbesThe ComfortNext Lux touts the same Responsive Air feature that I first saw with Sleep Number's P6 model. Essentially, this feature allows sensors in the bed to detect high-pressure areas, and it will either inflate or deflate at that spot to counteract the pressure. It takes a bit of getting used to, hearing the bed adjust on its own accord, but it very much contributes to the overall pressure-relieving experience the bed delivers. It can also be toggled on and off within the app, just in case you find it disconcerting.
Kicking It
Photograph: Julia ForbesSleep Number offers three adjustable bases, any of which are compatible with this smart bed: the basic adjustable base, FlexFit 2, and FlexFit 3. I tested this with the FlexFit base model, which still provided a solid foundation for the mattress to shine. I used the Sleep Number app to adjust the head and foot of the bed to get comfy while reading before bed. Automatic, gentle under-bed lighting would glow as soon as I peeled back the covers in the middle of the night to check on my senior dog. This lighting also has three brightness levels, none of which I found harsh on my sleepy eyes.
Previously, I tested the FlexFit 3 adjustable base with Sleep Number’s P6 smart bed, another model dedicated to pressure relief. The main feature of this base is the foot-warming feature, which can be put on a timer to shut off after you’ve fallen asleep. Given my experience with the ComfortNext, if I had the FlexFit 3, it would have been a done deal for me to go out and get this duo. But even for the ComfortNext Lux mattress itself, it’s redefined how I look at softer beds, and it's still a tempting investment for my sleep.
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