Photography: Julia Forbes
Like 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 generally lean toward firmer lumbar support and weight distribution, which used to be between 40 and 50. Then a new recommendation popped up in the app: My firmness level was in the mid-70s, but getting softer could improve my sleep score, which Sleep Number calls its “SleepIQ score” and reports in its app. I decided to turn it down to a much softer firmness level of 35.
The SleepIQ score summarizes your nighttime sleep metrics, including heart rate variability, breathing rate, and time spent in each sleep stage. This data is compiled into a score that summarizes the quality of your sleep. The app’s score was still lower than what my Apple Watch SE would follow. However, when dogs jump in and out of the bed, the sensors track that movement and take it into account as well. Despite this, my Apple Watch showed a six-day streak of high sleep scores between 80 and 90. Since my body is still getting used to new beds with a multitude of mattresses to test, this is extremely rare for me. Previously, testing other smart beds or standard types of mattresses like memory foam or hybrid, I would get this type of quality sleep with medium firm or very firm mattresses, never soft.
What was clear after two weeks of testing was that, even at the firmest 100 setting, the ComfortNext Lux still felt only moderately firm. I started firm and got much softer, but the reality is that the plush foam layers of the ComfortNext Lux will always make you feel softer, no matter what level you choose. If you’re looking for a truly firm mattress, like one of our favorite firm options, the Firm Luxe Board—the ComfortNext Lux isn’t even remotely playing in the same league. This isn’t shocking, because almost all the smart beds I’ve tried lack the stiffness found in innerspring models.
You have your back
If you regularly suffer from back pain or have more serious spinal issues like scoliosis, I do not recommend this smart bed. My husband is part of this club, and according to him, the ComfortNext Lux is doable for a few days. After a while, he needs to move back to a firmer mattress to get the support his spine needs. To that end, the ComfortNext Lux’s lumbar support isn’t where it needs to be for full-time stomach sleepers or heavier sleepers who need lifting around their abdomen. A few adjustable bases will have lumbar support bars that protrude from the base, which would be a beneficial remedy 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. In short? Side sleepers. As a side sleeper, this mattress provides the level of cushioning I often need for my pressure points, with a satisfying amount of sinkage that feels cushioned to the joints. You really feel cocooned and not claustrophobic. For couples who sleep on their sides or backs, the prominence of the foam in the ComfortNext Lux also helped prevent movement from tipping the bed. However, it’s a little more difficult to move between sleeping positions because you’re working against a softer surface when rolling.
