Sleep Number c4 Mattress Review

Updated May, 2021
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While Sleep Number C4 is a fantastic mattress at this price point, our #1 pick for 2021 is SAATVA mattress. Saatva is a luxury mattress shipped to your door (unlike other bed in a box brands dropped off on your doorstep) w/ FREE white-glove delivery & setup. They have over 50,000 5-star reviews, and they're incredibly comfortable (for all sleep positions).

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Bottom Line

Sleep Number has been revolutionizing air mattresses for over three decades. They've designed Smart Beds that put you in control of your sleep. The c4 model features SleepIQ® tracking and intuitively adapts to your movements—all with added cushioning for proactive support. Try the c4 for 100 nights risk-free, today!

Get Sleep Number c4 if...

  • You sleep with a partner. The c4 comes with built-in dual-sided adjustability, so you and your partner can choose your own firmness levels.
  • You need extra support. The c4 comes with a 3" gel-infused comfort layer for enhanced cushioning and resilient, pro-active support.
  • You're a combination sleeper. The c4 has 50% more gel memory foam than the c2 model. This gives it a slightly more plush feel—suitable for all sleeping positions.

Skip Sleep Number c4 if...

  • You want to keep things simple. The c4 model requires the use of either the Sleep IQ® mobile app or Sleep Number remote to control the firmness level. If you aren't particularly tech saavy, this might not be the right choice for you.
  • You want an all-foam mattress. All Sleep Number Classic Series models, including c4, use air chambers at their core to pump more or less air depending on your controlled settings.


  • Has 50% more gel memory foam than the c2 model
  • Dual-sided adjustability, ideal for couples who prefer different firmness levels
  • Effortlessly responds to your body and automatically adjusts accordingly


  • Bed requires assembly
  • A bit pricey, definitely an investment


The c4 Smart Bed is adjustable to your preferred firmness level with Sleep Number settings ranging from 1 (softest) to 100 (firmest).

The c4 model comes with a 3" gel-infused comfort layer for added cushioning and a more balanced feel. The air chambers allow you to adjust the firmness levels to your desired setting (whether that's sink-in soft or no-pushback firm).

Construction Key Points

  • The Sleep Number c4 is 9" tall.
  • Cover - A blend of rayon and polypropylene fabrics with a soft fiberfill material sewn directly into the cover for nice, breathable comfort.
  • Comfort Layer - 3" gel-infused comfort layer provides proactive pressure-relieving support.
  • Air Chambers - Depending on the size, the c4 is built with either single or dual-sided air chambers. The chambers are connected to a 4-foot long pump (hidden within the mattress) that inflates or deflates your mattress based on your specifications.

Support & Motion Isolation

The Sleep Number c4 model has excellent motion isolation due to the two separate air chambers, one on each side of the mattress. Any motion stays on individual sides of the bed.

The c4 contains foam border walls providing superb edge-to-edge support.

Since the air chambers on each side of the bed are individually adjustable, the middle is susceptible to a slight sag if one side is firmer or softer than the other.

Reasons to Buy Sleep Number c4

  1. This is a great choice for people who tend to sleep hot. The Sleep Number c4 Smart Bed keeps quite cool as it's constructed with air rather than a denser memory foam.
  2. If you sleep with a partner, this bed is a perfect solution. The Queen size and up comes with 2 air chambers (one on each side) that allows you and your partner to adjust your side to your personal comfort level.
  3. If you have back problems, the Sleep Number c4 Bed is a perfect match. Being adjustable, the Sleep Number c4 model contours to your lower back and hips based on your preferred firmness level setting. This pressurized support and added cushioning brings ample pain relief where you need it most.

Where can I find a great, affordable mattress (in 2021)?

If you're searching for an affordable mattress that offers a wide range of comfort and pressure relief, we've compiled a list of mattresses for you to consider:

  1. Saatva Mattress - fantastic for all sleep positions, and is rated our Best Mattress of 2021.
  2. Idle Sleep - great for responsive pressure relief.
  3. Puffy - feels like you're sleeping on a cool cloud (at a good price).
  4. Ghostbed - beautiful, plush cover w/ aerated latex and healthy spinal alignment.
  5. Winkbeds - 3-stage back relief with free shipping and returns.

Read our short, well-researched 10 Best Mattresses of 2021, here. Our ultimate goal is to help you pick your perfect mattress online, today!

Check Price →
Get $200 off, purchases over $1000!

Saatva is our top pick for the #1 mattress in 2020! They're a luxury mattress shipped with FREE white-glove delivery & setup (different than regular bed in a box brands put on your doorstep). They have over 50,000 reviews.

Check Price →
Get $200 off your order of $1,000 or more, today!