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Sleep Number Classic Series Mattress Review

Sleep Number is among the most well-known mattress manufacturers, and their 360 Smart Beds Classic series demonstrates why many customers are loyal to the brand. Consisting of two models — the C2 and C4 — with slightly different firmness ranges and construction, the Classic series offers sleepers an adjustable airbed at an affordable price point.

Both the C2 and C4 models have a dual-air chamber support core. These can be adjusted to have different firmness levels by adding or removing air at the touch of a button. However, the more affordable Classic series does not have the wide range of the other mattresses in the 360 Smart Beds collection, like the Performance and Innovation series.

The C2 has a 2-inch comfort layer of gel-infused polyfoam and a rayon-blend cover, while the pricier C4 features a 3-inch layer of gel-infused polyfoam and uses a polyester-blend cover. This slight difference in construction gives the C2 a firmness range of approximately medium firm to firm, while the C4 ranges from medium to firm.

As part of the Sleep Number’s 360 Smart Beds collection, the Classic series also features integrated SleepIQ sleep tracking technology.

We’ll walk you through everything you should know before buying a Sleep Number mattress. In addition to who the Classic series is best for and how both models perform under real-life conditions, we’ll go into detail on their construction, the company’s policies, and more.

Sleep Number Mattresses At-A-Glance

Sleep Number 360 c2 Smart Bed Sleep Number 360 p5 Smart Bed Sleep Number 360 i8 Smart Bed
Firmness Adjustable (6-8) Adjustable (Fully) Adjustable (Fully)
Mattress Type Airbed Airbed Airbed
Height 8” 10" 12"
Price (Queen) $999 $2,399 $3,599

Sleep Number Classic Series Mattress Review: Our Verdict

Overall, we believe both mattresses in the Classic series — the C2 and C4 — are capable of offering both comfort and support to a wide range of sleepers. With adjustable firmness levels and balanced construction, both models have excellent appeal across both weight and preferred sleep position categories.

However, the mattresses are not identical. The C2 is less expensive than the C4, with a firmer feel and a thinner comfort layer. The C4, then, tends to be slightly softer and has a wider range of adjustment, as well as more support for sleepers over 130 pounds. It is also significantly more expensive than the C2, which is the least expensive of Sleep Number’s sleep-tracking 360 Smart collection.

Choose The Sleep Number Classic Series if...
  • You’re looking for an adjustable firmness level
  • You’re shopping for an airbed on a tight budget
  • You’re part of a couple and have similar but differing needs from a bed
  • You enjoy a balanced feel with moderate conforming
Keep Shopping if...
  • You prefer a bed with a soft or medium soft firmness level
  • You require deep, high-performance pressure relief
  • You sleep very warm

How Much Is the Sleep Number Classic Series Mattress?

The Sleep Number C2 has a low price-point that makes it one of the least expensive airbeds on the market. The slightly thicker C4, on the other hand, comes in at a significantly higher cost. Given that the average airbed is over $2,200, the Classic series is perfect for shoppers on a budget. The prices for the Classic Series tend to be more comparable to all-foam or hybrid beds.

Of course, this low price comes with a cost. Instead of being fully adjustable like the more expensive Sleep Number lines, the Classic series ranges more from medium to firm, depending on the model. Similarly, the less-pricey C2 has a simple remote, as opposed to the C4’s remote with a digital firmness reading.

Sizes Dimensions Weight Price
Twin 39” x 75” x 12” N/A C2: $599
C4: $1399
Twin XL 39” x 80” x 12” N/A C2: $699
C4: $1499
Full 54” x 75” x 12” N/A C2: $799
C4: $1549
Queen 60” x 80” x 12” N/A C2: $999
C4: $1699
King 76” x 80” x 12” N/A C2: $1499
C4: $2199
California King 72” x 84” x 12” N/A C2: $1499
C4: $2199

How Does the Sleep Number Classic Series Feel?

Both the C2 and C4 models from the Classic series offer a balanced feel, with low to moderate cradling around the body and the feeling of sleeping both ‘on’ and ‘in’ the mattress. Gel-infused polyfoam provides a slightly more resilient feel than memory foam, and the fairly thin comfort layers in both models prevent sleepers from feeling like they’re sinking into the bed. However, they still provide adequate pressure relief for the majority of sleepers.

Although the C2 and C4 beds share many similarities, they do have their differences as well. The C4’s extra inch of polyfoam makes it softer than the C2, allowing it to range from medium to firm. The C2, on the other hand, ranges only from medium firm to firm. The C4 also has a plusher feel with slightly more contouring around the body, though both mattresses performed similarly in our pressure relief testing.

The dual air chamber support core provides firm yet subtle support in both models. While some of our C2 testers reported being able to feel the chambers slightly through the comfort layer, there were few reports of this with the C4.

What Is the Sleep Number Classic Series Made Of?

The Classic series pairs gel-infused polyfoam with an adjustable, dual air chamber support core to offer sleepers a personalized night’s sleep. As Sleep Number’s budget-minded 360 Smart Bed series, both Classic models are significantly less complex than their Performance and Innovation series. However, despite being thinner and built with fewer layers, the Classic series still features high-quality construction with premium materials.

In addition to the usual mattress construction layers, the Classic series also has integrated smart SleepIQ technology to track your sleep. Both models also have a remote for firmness adjustment at the touch of a button; this remote is a simple higher or lower toggle for the C2, while the C4 has a more complex remote with a digital reading of the current firmness level, or “sleep number.”

Cover Material
The C2 uses a rayon-polypropylene blend for its cover, while the C4 uses both polyester and polypropylene. In both cases, the cover is smooth, slightly stretchy, and resistant to sagging even at the lowest firmness setting.

Comfort Layers
The C2 and C4 models are primarily distinguished by their comfort layer. Both feature gel-infused polyfoam, but this layer is two inches in the C2 and three inches in the C4. This minor difference gives the two models different firmness ranges, as well as slightly different feels. Polyfoam offers a less ‘cradling’ feel than memory foam, and the gel infusion is thought to promote better airflow and temperature neutrality.

Support Core
Although other construction details are also important, Sleep Number’s mattresses are set apart by their air chamber support cores. The Classic series features dual chambers, allowing users to set a different firmness level on each side of the bed. Discreet pumps release or take in air as needed to set the level, which can be done with the press of a button. Overall, airbeds like the Classic series provide very balanced support, though with minimal bounciness.

Does it Isolate Motion?

Rating: 3/5
Although both the C2 and C4 are capable of isolating enough motion for most sleepers, their performance here is only average. Most of our testers found that both mattresses transferred enough motion for them to feel when their partner changed positions or got out of bed. Many sleepers reported that, while they were aware of it while still awake, it wasn’t significant enough to wake them from sleep.

As the Classic series features dual air chambers, the majority of the motion transfer comes from the position of the comfort layer on the chambers, rather than the support core itself. This slightly changes the feeling of the motion transfer, making it more of a gentle wave than the compression of coil, spring, or all-foam support systems. Overall, we expect that both the C2 and C4 offer enough performance in this category to satisfy most couples.

Does it Sleep Cool?

Rating: 3/5
Although the Classic series has better temperature neutrality than some airbeds, it still has only average performance in this category. Polyfoam has poor airflow, and the air chamber system prevents airflow through the bed. However, Sleep Number combats this through the use of gel-infused polyfoam, which is thought to improve both airflow and heat retention. The company has also designed both models to minimize trapped air and moisture between the comfort and support layers.

The majority of sleep testers found it slept only slightly warm after a full night of sleep, though very hot sleepers reported a feeling of clamminess after several hours. Still, due to their careful construction, both the C2 and C4 models have average temperature neutrality and should suit most sleepers, whether they sleep warm or cool.

Will It Sag Along the Edges?

Rating: 3/5 (C2), 2/5 (C4)
Though the Classic series has surprisingly good performance for its price-point, it's edge support leaves something to be desired. This is particularly true for the C4, which came in at a score of 2 out of 5, but the C2, with a score of 3 out of 5, also struggles in some situations.

When airbeds are at their firmest, they tend to have minimal sagging at the edges. However, as air is released to make them softer, the edges can lose the structure that offers them support. This is most obvious with the C4, as even firmer settings must contend with the thicker polyfoam layer’s lack of perimeter stability. The C2, though offering very good edge support when very firm, still falters at softer settings.

Is It Good for Sex?

Rating: 3/5
The Sleep Number classic series has an average suitability for sex. Performance in this category is linked to performance in a number of other areas — from edge support, to bounciness, to ease of motion and other categories. However, as both the C2 and C4 do not excel in these areas, their suitability for sex is equally ordinary.

Most couples are likely to find that, while the Classic series fails to offer the responsiveness and support necessary for a high score here, it also lacks the downsides of some mattresses. With foam layers of either 3 or 2 inches, neither model has the deep cradling effect that can make movement difficult. As mentioned above, edge support also increases slightly at firmer levels, allowing couples to use more of the bed’s surface.

What About Off-gassing?

Rating: 4/5
With their relatively thin polyfoam comfort layers and air chamber support cores, both the C2 and C4 have minimal off-gassing. When first set up, the bed has a faint but distinct odor thanks to the volatile organic compounds (VOCs) released from the foam. A byproduct of the manufacturing process, these VOCs are relatively harmless and break down very quickly.

In the case of the Classic series, testers felt comfortable sleeping on their new bed within 12 hours of set-up. Within 24 hours testers could only smell the off-gassing with their face very close to the mattress, and the odor was gone entirely within 48 hours

What Type of Sleeper Is the Sleep Number Classic Series Best for?

As adjustable airbeds, both the C2 and C4 offer sleepers a wider degree of suitability than many all-foam or pocketed coil options. However, their smaller range of adjustment compared to the fully adjustable beds in Sleep Number’s Performance and Innovation series does make them less suitable for some positions.

The C4 has a wider range of potential firmness levels, ranging from medium to firm. The C2, on the other hand, is limited to medium firm to firm. Furthermore, the two beds have slightly different pressure-relieving qualities, with the C4’s thicker polyfoam layer providing more comfort for positions that typically create pressure points.

Between them, both the C2 and C4 are capable of supporting the majority of sleepers, regardless of their preferred position. This is dependent on the firmness adjustment, as sleepers who have “found their sleep number” report a much better sleep than those still in the process of trying out different levels. Due to these factors, customers should expect a period of adjustment and testing when they first receive their C2 or C4 mattress.

Side Sleepers: The C4 is slightly more effective for side sleepers, as the thicker polyfoam cushions prominent areas at the shoulder and hip. However, both mattresses offer this category fairly good performance, with side sleepers appreciating both models regardless of how much they weigh.

Stomach Sleepers: Stomach sleepers require good support for both the hips and the upper body in order to prevent next-day stiffness or pain. While among the least suitable sleep positions for the Classic series, our stomach sleeping testers still reported that both the C2 and C4 offered enough support for a comfortable night’s sleep. All the same, stomach sleepers in search of enhanced support may want to consider Sleep Number’s Performance series.

Back Sleepers: Among our testers, back sleepers were some of the biggest fans of the Classic series. This was more dependent on choosing the right model than with some other positions, with back sleepers of different weights preferring either the C2 or C4.

How Does Body Weight Impact Performance?

Mattress suitability is always related to an individual’s sleep position preference, but weight almost always plays its own major role. Beds with adjustable firmness levels are more flexible in terms of who they’re suitable for, as firmness level is one reason for the importance of weight categories.

All the same, the Classic series has limited adjustability, meaning that the softer C4 is slightly more appealing to sleepers under 130 pounds than the C2. The opposite is also broadly true, with sleepers above 130 pounds tending to prefer the C2, though this was not true in every category. For example, side sleepers between 130 and 230 pounds reported that they enjoyed both the support of the C2 and the thicker comfort layer of the C4.

Many sleepers under 130 pounds prefer a softer-feeling mattress than either the C2 or C4. If this is true of your needs, you may prefer the fully adjustable Performance or Innovation airbed series from Sleep Number.

Is it Good for Couples?

Couples are likely to enjoy the Sleep Number Classic Series, but may have concerns about its performance in a few crucial areas.

One of the most critical factors when couples choose an airbed is ensuring each side can be adjusted individually. Since this adjustment is one of the best features of an airbed, it makes little sense to resign yourself to an imperfect compromise between your and your partner’s needs. With its dual air chamber design, the Classic series fits this requirement.

However, couples may be let down by the edge support, suitability for sex, and temperature neutrality of both the C2 and C4 models. Although almost always coming in with an average score that’s likely to please most customers, both models score lower in these categories than others. If you are looking for premium performance, you may want to choose one of Sleep Number’s other 360 Smart mattresses.

Sleep Number's Trial, Warranty, and Shipping Policies

Availability Sleep Number mattresses, including the Classic series, can only be bought through Sleep Number’s official website, or at one of their branded showrooms across the USA.
Shipping Sleep Number ships their mattresses only within the contiguous U.S. states and Alaska. Their airbeds are shipped with their various parts packaged separately, making set-up more involved than mattresses that are simply rolled and compressed for shipment. However, since there is no air in the chambers until it is set up, this makes the entire shipment process far more manageable.

While some Sleep Number products are available by USPS, the Classic series is shipped only with Home Delivery. This service, which we detail in the section below, costs $199 for most customers and $249 in some remote areas.

Additional Services Smart airbed mattresses like the C2 and C4 tend to be more difficult to set up than standard mattresses. To help customers with this process, Sleep Number offers Home Delivery for $199, or $249 in remote regions. This is their only shipping option for the Classic Series, and the fee is non-refundable.

Sleep Number professionals will arrive with your mattress, set it up as you desire, and remove your old mattress for disposal or recycling.

Sleep Trial Sleep Number offers a 100-night trial for all of its mattresses, including both models in the Classic series.

The customer must wait out an initial 30-day break-in period, which the company requires in order for customers to become accustomed to their new bed and decide whether or not it works for them. After this period, customers who are not satisfied may exchange their mattress, or send in their mattress for a full refund.

Customers are responsible for the shipping costs of returning their mattress to Sleep Number.

Warranty All of the beds in Sleep Number’s 360 Smart collection come with a 25-year warranty which is prorated after 2 years. Beginning with year three, owners must pay a prorated charge of 20% of the mattress’s original price. This increases by 4% per year until the nineteenth year. Then, from years 20 through 25, owners are responsible for 96% of the original product price.

The warranty is non-transferable and does not cover ordinary wear and tear, tampering with the Firmness Control System, or physical damage that occurs after the mattress has been delivered.