Photo: Julia Forbes
Like any Sleep Number smart bed, the ComfortNext Lux offers 100 firmness levels, and the one you choose is your “sleep number,” or the firmness you prefer to sleep at. I tend to lean towards stiffness for lumbar support and weight distribution, which used to be in the 40 to 50 range. Then, a new recommendation appeared in the app—my fitness level was in the mid-70s, but going slower might improve my sleep score, which Sleep Number calls the “SleepIQ Score” and reports in its app. I decided to lower it to a soft 35 hardness level.
The SleepIQ score summarizes your nightly sleep metrics, including variability in heart rate, 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 was always a little slower than what my Apple Watch SE could keep up with. However, with dogs jumping in and out of bed, the sensors track that movement and take it into account, too. Despite this, my Apple Watch showed a six-day streak of high scores of 80 to 90. Given that my body is always getting used to new beds with a revolving door of mattresses to be tested, this is very rare for me. Previously, when I was testing other smart beds or standard types of mattresses like memory foam or hybrid, I would achieve this type of sleep quality with firm or firm mattresses, never soft.
What became clear after two weeks of testing was that, even in the most extreme 100-degree conditions, the ComfortNext Lux still felt just as stiff. I started out firm and softened, but the truth is that ComfortNext Lux’s sweet foam layers will always make whatever level you choose feel soft. If you’re looking for a really firm mattress—like one of our favorite firm options, the Plank Firm Luxe—the ComfortNext Lux isn’t even remotely in the same league. This isn’t surprising, as almost every smart bed I’ve tried lacks the firmness you’d find in coil-based designs.
He got his back
If you suffer from chronic back pain or have severe back conditions such as scoliosis, I do not recommend this smart bed. My husband is part of this club, and according to him, ComfortNext Lux is possible for a few days. After a while, he needs to go back to a firmer mattress to get the support his spine needs. So far, the ComfortNext Lux lumbar support is not where it should be for full-time stomach sleepers or heavy sleepers who need a lift in their midsection. Some flexible bases will have lumbar support bars that project from the base, which can be a beneficial solution here. Unfortunately, this feature is not available on Sleep Number bases at this time, and I do not recommend pairing this smart bed with an adjustable base from another brand.
If not for back pain, you may be wondering who the ComfortNext Lux works best for. Briefly? Side sleepers. As a side sleeper myself, this mattress provides the level of cushioning I often crave for my pressure points, with a satisfying amount of cushioning inside that makes joints feel comfortable. You feel really comfortable, and not in a claustrophobic way. For couples who may be side or back sleepers, the foam padding in the ComfortNext Lux also helps prevent movement from shaking the bed. However, it is a bit difficult to move between sleeping areas because you are working on a soft surface as you roll.
