Written by Lisa Bowman, Writer
Sleep Number launched its 360® range of smart air beds in 2017, offering luxury air beds with adjustable firmness and smart technology. The air support system inflates or deflates depending on your firmness preference, with 20 possible options. All 360® beds feature Sleep Number’s SleepIQ® technology, which uses mattress sensors to give you insights into the quality of your sleep via the SleepIQ® app.
Today, we’re looking at the Sleep Number 360® c4, which is in the Classic series. This series features the brand’s entry-level beds, and the c4 is the second most affordable bed (after the c2). Is it as versatile as they say? Let’s find out.
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
$300 off
Material
Trial Period
100 nights
Shipping Method
Flat-rate white glove delivery
Firmness
Multiple firmness options
Warranty
15-year limited warranty
Price Range
$$$$$
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Warranty
15-year limited warranty
Firmness
Multiple firmness options
Shipping Method
Flat-rate white glove delivery
Trial Period
100 nights
Price Range
$$$$$
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Firmness
Multiple firmness options
Trial Period
100 nights
Warranty
15-year limited warranty
Shipping Method
Flat-rate white glove delivery
Price Range
$$$$$
Who We Recommend The Sleep Number 360® c4 For:
- Couples – The versatility of the c4 makes it ideal for couples who have different firmness preferences. Beds designed for two people have two air chambers, so you can customize the firmness on each side.
- Stomach sleepers – With its thinner comfort layer, this is one of the firmer Sleep Number beds, making it great for stomach sleepers, who should feel well supported in the hip area.
- Sleep Number fans with less money to spend – If you love the idea of owning a Sleep Number smart bed but can’t afford one of their more luxurious models, the c4 offers the same integrated SleepIQ® technology as the other beds but costs less as there’s less cushioning.
Who We Don’t Recommend The Sleep Number 360® c4 For:
- People with joint pain – The c4 has an adjustable firmness but even on the softest firmness level, it‘s not the plushest of mattresses as the comfort layer is only 3 inches thick. Those seeking deep pressure relief for sensitive joints would be better off on a traditional memory foam bed or the Sleep Number 360® m7.
- Budget shoppers – While the c4 is Sleep Number’s second cheapest mattress (after the c2), at 1,899 dollars for a Queen, it’s not the best value for a bed that has such a thin comfort layer.
Find our picks for the Best Sleep Number Alternatives here.
First Impressions: Firmness & Feel
Firmness Scale: Adjustable
We rate mattress firmness on a scale from 1 to 10. That being said, it’s difficult to give this bed a rating as the whole point is that it’s adjustable.
Sleep Number beds have 20 possible firmness ratings – or Sleep Numbers, as they’re called – rising in increments of five, from 1 to 100. These are programmed via the remote control or SleepIQ® app. You can even let the bed’s Responsive Air® technology automatically adjust while you sleep, responding to your movements.
The c4 is considered one of Sleep Number’s firmest beds, due to its thin comfort layer, so even on its plushest setting, it shouldn’t feel soft.
How Does It Feel?
The numbers in Sleep Number bed names represent the amount of cushioning in the bed – the higher the number, the softer the bed. This makes the c4 one of the brand’s firmest beds (the c2 is its firmest), with a relatively thin 3-inch comfort layer. While the gel-infused poly foam and fiberfill quilting do offer a decent level of contouring and pressure relief, you’re unlikely to experience a super plush feel that a more cushioned bed might offer.
What We Like About the Sleep Number 360® c4
- Removable cover – The cover can be removed, and while it’s not machine-washable, it’s much easier to spot-clean any spills when the cover isn’t sitting on top of the mattress.
- Good edge support – With its reinforced foam wall around the perimeter and thin comfort layers, the c4 offers good edge support, making it easy to spread out and use the whole surface area of the bed.
- Financing is available – Sleep Number offers an 18-month interest-free financing option on the c4, which is handy if you need a new mattress but can’t afford the total cost upfront.
Our Sleep Number 360® c4 Complaints
- Gap in the middle – A common complaint for dual-chambered Sleep Number beds is that a ‘trench’ forms in the middle where the two air chambers meet, especially if the chambers are on wildly different settings. This can make it uncomfortable to sleep in the center with your partner.
- Tech issues – The more high-tech a bed is, the more risk there is of things going wrong. Unfortunately, there are some online reviews complaining of issues with the remote and pumps, which could cause headaches down the line.
Testing the Sleep Number 360® c4 Mattress: How it Performed
Online mattress sales changed the bed industry, but it can feel risky to spend money on a mattress you’ve never even sat on. That’s why we’re here – we do all the preliminary testing for you, to give you as much information as you need to make a good decision. Our tests involve looking at qualities such as firmness, support, pressure relief, cooling, motion isolation, and bounce, as well as seeing how accommodating the bed is in each sleep position.
Sleeping Positions for Different Body Types
Sleep Number beds have a maximum weight limit of 400 pounds per air chamber – so a Twin or Twin XL can hold a total weight of 400 pounds, and a Full size and up can hold a total weight of 800 pounds. However, due to the minimal cushioning in the c4, we don’t think this bed would be the most comfortable option for some heavyweight people, who may find themselves resting on the firm air chamber.
Side Sleepers
- Lightweight Sleepers – Lightweight side sleepers should experience a good balance of cushioning and support on the c4, as they won’t be heavy enough to sag into the thin comfort layer. This should provide the right amount of contouring at the hips and shoulders, though some may prefer a plusher mattress.
- Average Weight Sleepers – Average-weight side sleepers should also find this bed supportive and contouring, especially on a softer setting, but again, a bed with more cushioning may be more comfortable for some.
- Heavyweight Sleepers – We think some heavyweight people could be comfortable while sleeping on their side but many may find themselves disappearing through the comfort layer and resting on the air support, which could cause a buildup of pressure at the joints.
Back Sleepers
- Lightweight Sleepers – We think this bed could be a great choice for lightweight back sleepers, who will likely experience great spinal support and soft cushioning.
- Average Weight Sleepers – Average-weight back sleepers should find the c4 a treat, especially if they love a firm bed for back sleeping. The lumbar area should feel lifted and supported, reducing the risk of back pain.
- Heavyweight Sleepers – While we think this bed could be a good choice for heavyweight back sleepers, who could find good support on one of the firmer settings, some may prefer a bed with a thicker comfort layer.
Stomach Sleepers
- Lightweight Sleepers – Stomach sleepers need firm support to keep the hips lifted. Lightweight stomach sleepers should definitely find that on the c4, with some comfortable cushioning for the joints.
- Average Weight Sleepers – Average-weight stomach sleepers should feel comfortably supported on this firm mattress, experiencing healthy spine alignment and nice pressure relief.
- Heavyweight Sleepers – While we think a lot of heavyweight people could experience great support while sleeping on their front, some may find themselves pressing into the support layer, causing pressure buildup at the sensitive hip area.
Pressure Relief & Pain
The gel-infused poly foam layer in the c4 has three zones, designed to offer pressure relief at sensitive areas like the head, neck, back, and hips. While it doesn’t feature a whole lot of cushioning, the gel foam combined with the soft fiberfill quilting in the cover does offer decent pressure relief for many sleepers, although some heavier sleepers may find themselves sinking through the thin comfort layer and resting on the firm support layer, which could lead to pressure build-up at the joints.
Back Pain – The c4 offers firm support, so is a great choice for sleepers who experience back pain, as it should keep the lumbar area lifted when back and front sleeping, preventing lower back pain.
Hip Pain – The c4 is designed to offer gentle contouring, and it should offer this for most sleepers, although heavier sleepers and those with severe hip pain may experience better pressure relief on a bed with a thicker comfort layer.
Shoulder Pain – The level of cushioning on this bed could be enough for light to average-weight side sleepers with shoulder pain, but heavier folk may find more comfort on a plusher layer of foam.
Support
The c4’s main support system is the air chamber(s), which increases or decreases support as needed, either automatically or manually. The gel-infused poly foam has three zones for additional contouring support at the head, neck, back, and hips.
While the c4 is pretty versatile, we think it’s most suitable for light to average-weight sleepers. Most heavyweight people should feel adequately supported, but they may run into issues with the thin comfort layer not providing enough cushioning for their body weight, which could cause a buildup of pressure at sensitive joints.
Motion Transfer
Are you a light sleeper who shares your bed with a partner that tosses and turns a lot? It’s hardly a recipe for a good night’s sleep – unless you have a bed with good motion isolation. What this means is that any movement made on the restless sleeper’s side of the bed should stay there, leaving you undisturbed.
We found the c4 to have good motion isolation, especially on the beds that feature dual air chambers (Full size or larger).
Temperature Regulation / Cooling
Air beds are known for sleeping quite cool because they’re not good insulators. However, they can become warm if there are thick layers of foam added on top. The c4 bed sleeps quite cool, as it only has a thin comfort layer, so it could be a good choice for hot sleepers who love a firmer mattress.
Performance for Couples
Dual-chambered Sleep Number beds are an obvious choice for couples, thanks to the ability to customize firmness on each side of the bed. You can even raise and lower both sides individually if you purchase one of Sleep Number’s FlexTop or Split beds and bases (available in selected sizes). All FlexTop bases have a Partner Snore feature that allows you to raise the head of your bedmate if they’re breathing too loud.
The c4 also sleeps cool and has great motion isolation and good edge support, which are all benefits to couples. Additionally, the bed has some bounce, making it good for sex. The only major downside for couples with this bed is the potential for a dip in the middle if you and your significant other have vastly different firmness preferences.
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Trial Period
100 nights
Shipping Method
Flat-rate white glove delivery
Firmness
Multiple firmness options
Warranty
15-year limited warranty
Price Range
$$$$$
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Warranty
15-year limited warranty
Firmness
Multiple firmness options
Shipping Method
Flat-rate white glove delivery
Trial Period
100 nights
Price Range
$$$$$
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Firmness
Multiple firmness options
Trial Period
100 nights
Warranty
15-year limited warranty
Shipping Method
Flat-rate white glove delivery
Price Range
$$$$$
Preference-based Features
Adjustable Firmness Options
Sleep Number 360® beds feature air inflation technology that allows you to adjust the firmness level, out of a choice of 20. Responsive Air™ technology will even change firmness as you sleep, based on your movements and sleeping position.
Smart Technology
If you love your bed with a side of tech, the c4 smart bed could be a good choice – it features SmartIQ® technology that utilizes biometric sensors in the mattress to give insights into your sleep quality along with tips on how to get a better night’s sleep.
Good Edge Support
If you have limited mobility and need stability when getting in and out of bed, or if you’re a couple that likes to use the whole surface area of the bed, then you need good edge support. The c4 provides this, thanks to its firm feel and foam perimeter wall, which makes sitting or lying near the edge feel more secure.
Adjustable Base Compatible
The Sleep Number 360® c4 can be used on an existing adjustable base, although Sleep Number sells its own FlexFit™ Smart Base, which comes in three versions. However, please note that Sleep Number’s adjustable bases are not returnable and not included in the 100-night trial.
Construction: What’s Inside Sleep Number 360® c4?
The Sleep Number 360® c4 is a 9-inch smart bed that allows users to program their own firmness level from a choice of 20 settings. This is provided by the air support system – Twin and Twin XL sizes feature one air chamber, while Full sizes and larger have two air chambers, with the ability to customize each side of the bed.
The mattress starts with a removable breathable polyester and polypropylene stretch-knit cover.
- Quilted to the cover is a 1.5-inch layer of fiberfill material to provide soft cushioning, followed by a 1.5-inch layer of gel-infused poly foam that’s designed to offer pressure relief and contouring. This three-zoned foam offers additional support for the head, neck, back, and hips.
- The air chamber(s) make up the support layer and are constructed with 24-gauge vulcanized rubber and cotton fabric on the exterior. Each chamber features a hose and pump to inflate or deflate the bed to your desired Sleep Number. This can either be programmed manually via the SleepIQ® app or a remote or automatically with Responsive Air® technology, which allows the bed to adjust firmness hourly while you sleep, depending on your sleeping position.
- A foam wall perimeter provides edge support.
The Sleep Number 360® c4 requires a power source within 5 feet, and a wifi connection to make use of the SleepIQ® data. However, should your internet fail, you can control the bed via Bluetooth or remote.
Unboxing & Off-Gassing
The Sleep Number 360® c4 has to be delivered using Sleep Number’s premium delivery service, which costs 249 dollars. They’ll set the bed up for you and show you how to use it. Your old mattress will either be moved to another room or taken away for recycling, at a cost of 49 dollars.
As with any bed containing foam, there may be a slight off-gassing odor, which is harmless and the result of chemical byproducts escaping after the foam is unboxed. Once your bed has been set up, you can jump on for a nap.
Certifications
- Eco-Friendly Certifications – The foams in this bed are CertiPUR-US® certified. CertiPUR-US® is a third-party program that ensures the foams meet rigorous health and safety standards. This means they don’t contain harmful substances like ozone depleters, PBDEs, heavy metals, formaldehyde, and phthalates. They should also have low volatile organic compound (VOC) emissions.
Coupons, Trials, Warranties, and Shipping
- Shipping – Sleep Number requires its 360® c4 bed to be delivered using its premium delivery service, which costs 249 dollars and includes the removal of your old mattress to another room, set-up of your new mattress, and a demonstration of how to use the smart bed and SleepIQ® app. This premium service is available to select areas in all 50 states and may be available outside of these areas for an additional fee. For an extra 49 dollars, they’ll take away your old mattress for recycling.
- Trial – You get 100 nights to try out the Sleep Number 360® c4.
- Warranty – Sleep Number offers a 15-year warranty. All costs of repairs are covered in the first year, but from the second year, you’ll have to pay 30 percent of the cost. This rises in increments every year, maxing out at 85 percent in the fifteenth (and final) year.
- Return Policy – As long as you’ve had the bed for at least 30 nights, you can initiate a return within the 100-night trial to receive a full refund (minus shipping fees). However, you’re liable for any return shipping fees – Sleep Number can arrange this for 249 dollars plus tax.
Sizes & Prices
| Size | Dimensions (inches) | Price (w/o discount) |
| Twin | 38” x 75” x 9” | $1,599 |
| Twin XL | 38” x 80” x 9” | $1,699 |
| Full | 54” x 75” x 9” | $1,749 |
| Queen | 60” x 80” x 9” | $1,899 |
| King | 76” x 80” x 9” | $2,399 |
| Cali King | 72” x 84” x 9” | $2,399 |
| Split King | 76” x 80” x 9” | $2,699 |
| FlexTop King | 76” x 80” x 9” | $2,699 |
| FlexTop Cali King | 72” x 84” x 9” | $2,699 |
Frequently Asked Questions
How thick is the Sleep Number C4 mattress?
The Sleep Number 360® c4 is 9 inches thick, making it the brand’s second-thinnest mattress. The thinnest mattress is the c2 at 8 inches tall, and the thickest are the Climate360™ and i10 at 13 inches tall.
What is the difference between the Sleep Number C2 and C4?
The c2 and c4 are in Sleep Number’s Classic series and are the brand’s most affordable beds. They both feature the air support system, but the c2 is 8 inches tall with a 2-inch comfort layer, while the c4 is 9 inches tall with a 3-inch comfort layer. The c2 and c4 are 1,099 dollars and 1,899 dollars for a Queen, respectively.
How much does a 360® Sleep Number cost?
The cost of a 360® Sleep Number bed varies. The cheapest is the c2, at 1,099 dollars for a Queen, while the most expensive is the Climate360®, which includes a base and costs 9,999 dollars for a Queen.
Is the Sleep Number c4 better than the c2?
It depends on what you’re after – the c4 has an extra inch of comfort material, making it slightly softer than the c2. So, if you love an extra-firm bed, the c2 could be the one for you, but if you’re in the market for a firm feel with a little cushioning, the c4 may be right up your alley.
What is the lifespan of a Sleep Number bed?
Sleep Number 360® beds are designed to last for at least 15 years and come with a 15-year limited warranty. While this sounds great, be aware that the warranty only covers the full cost of repair in the first year. After that, you’ll have to pay a percentage of the cost, which increases each year.
Sleep Number 360® c4 vs Other Brands
Sleep Number 360® c4 vs Eight Sleep Pod
Product
Type
Score
Product
Type
Score
Product
Type
Score
Who We Recommend the Sleep Number 360® c4 For
- Couples with differing firmness preferences
- Those looking for good pressure relief
- Smart bed fans on a smaller budget
Who We Recommend the Eight Sleep Pod For
**Editor’s note: Eight Sleep is no longer selling their mattress as a separate item. You can now purchase the mattress as an add-on with the Pod Cover.
- Couples with differing temperature preferences
- Those looking for good pressure relief
- People wanting an in-built vibrating alarm clock
Read our Eight Sleep review if you think this bed is right for you.
Sleep Number 360® c4 vs Saatva Solaire
Product
Type
Score
Product
Type
Score
Who We Recommend the Sleep Number 360® c4 For
- Smart bed shoppers on a smaller budget
- Those excited by an integrated sleep data app
- People who like a firmer feel with less cushioning
Who We Recommend the Saatva Solaire For
- Eco-conscious shoppers
- Those seeking good pressure relief
- Hot sleepers
Read our Saatva Solaire mattress review if you think the Saatva Solaire is right for you.
Sleep Number 360® c4 vs Other Sleep Number Models
Sleep Number 360® c4 vs Sleep Number 360® iLE
Product
Type
Score
Product
Type
Score
Product
Type
Score
Who We Recommend the Sleep Number 360® c4 For
- Back sleepers
- Those who love a firm bed
- Shoppers wanting an entry-level Sleep Number bed
Who We Recommend the Sleep Number 360® iLE For
- Side sleepers
- People with joint pain
- Luxury shoppers
Read our Sleep Number 360® iLE mattress review if you think the Sleep Number 360® iLE is right for you.
Sleep Number 360® c4 vs Sleep Number 360® m7
Product
Type
Score
Product
Type
Score
Product
Type
Score
Who We Recommend the Sleep Number 360® c4 For
- Stomach sleepers
- Shoppers on a smaller budget
- Those who prefer a firmer bed
Who We Recommend the Sleep Number 360® m7 For
- Memory foam fans
- Side sleepers
- People looking for great pressure relief
Read our Sleep Number 360® m7 mattress review if you think the Sleep Number 360® m7 is right for you.
Overall Summary
Couples and combination sleepers should appreciate the feel of this adjustable bed, as well as those who are looking for insights into their sleep quality.
Side Sleepers
3/5
Light to average-weight side sleepers who only like a hint of plush will get on with this mattress, but those who prefer things a little more cushioned would be better off on a bed with a thicker comfort layer. Heavyweight side sleepers will likely find themselves experiencing pressure buildup at the hips and shoulders, due to the thin comfort layer.
Back Sleepers
4/5
With its overall firm feel, we think this mattress is a great choice for most back sleepers, who should feel well-supported, while also feeling comfortably cushioned. However, some heavier folk may find the comfort layer isn’t thick enough to stop their hips from sagging onto the firm support layer, which could be uncomfortable.
Stomach Sleepers
4/5
The firm feel of the c4 should be a treat for most stomach sleepers, who require that extra support to keep the hips lifted, preventing lower back pain. While most heavyweight front sleepers should get enough support from the c4, they may find the thin comfort layer doesn’t provide enough cushioning, which could cause pressure buildup at the hips.
Combination Sleepers
4/5
The c4 has Responsive Air® technology, which adjusts firmness overnight, depending on your movements – ideal for combination sleepers. Firm support, a thinner comfort layer, and a bit of bounce make the bed easy to move around on. However, it loses a point as some sleepers may find the mattress isn’t plush enough.
Couples
4/5
Couples should love the good motion isolation, edge support, cooling technology, and slight bounce from this bed The ability to customize firmness on both sides of the bed is also a huge benefit, but those who like to snuggle in the center of the bed may find themselves sagging into a trench that appears between the two air chambers.
Heavy Sleepers
3/5
Most heavyweight back and stomach sleepers should be able to find a Sleep Number that offers the required support, while still feeling lightly cushioned by the comfort layer. However, some may prefer a bed with a thicker comfort layer. Some side sleepers could feel comfortable, but we think most would find better pressure relief with thicker foam.
Lightweight Sleepers
4/5
Lightweight back and stomach sleepers should have a great time sleeping on this mattress, finding support from a firm Sleep Number while feeling cushioned by the gel-infused foam. It could also work for many side sleepers, but those with severe joint pain or those who prefer plush foam will probably be better off on a softer bed.
Average Weight Sleepers
4/5
Average-weight stomach and back sleepers should feel lightly cushioned and well-supported on this firm bed, experiencing healthy spine alignment, which should help alleviate back pain. Many side sleepers could also feel comfy, but if you have joint pain or know you love a ‘deep hug’ feel, a Sleep Number bed with a thicker comfort layer would suit you better.
Overall Value
3/5
Sleep Number’s second most affordable bed offers the same technology as the brand’s other models at a more affordable price. However, a very limited warranty along with multiple reports of malfunctions may mean this bed costs you down the line.
Our Verdict
The Sleep Number 360® c4 could be a great choice for those wishing to dip their toes into the Sleep Number brand without spending too much cash. With its air support system, the c4 is definitely not the one for those who love a more traditional feel, but technology fans and couples could appreciate the ability to customize both sides of the bed, have firmness adjusted automatically overnight, and get insights into their sleep quality.
Overall, we think couples, combination sleepers, and light to average-weight smart bed fans could be great candidates for this high-tech air mattress.
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Trial Period
100 nights
Shipping Method
Flat-rate white glove delivery
Firmness
Multiple firmness options
Warranty
15-year limited warranty
Price Range
$$$$$
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Warranty
15-year limited warranty
Firmness
Multiple firmness options
Shipping Method
Flat-rate white glove delivery
Trial Period
100 nights
Price Range
$$$$$
Sleep Number 360 c4 Smart Mattress
One of the more affordable Sleep Number smart beds, the c4 offers sleep tracking, adjustable firmness, and good support.
Material
Firmness
Multiple firmness options
Trial Period
100 nights
Warranty
15-year limited warranty
Shipping Method
Flat-rate white glove delivery
Price Range
$$$$$
Lisa Bowman
Writer
About Author
Lisa is a content writer for Sleep Advisor, which combines two of her greatest passions – writing and sleeping. She can also be found writing about fitness, sustainability and vegan food.
Combination Sleeper