Amerisleep AS5 Review 2026: Best for Side Sleepers?

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Amerisleep AS5 — Ultra-Soft Mattress for Side Sleepers

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Published April 2026 • By the MattressNut Editorial Team

A soft mattress that actually supports you — not just cushions you. Here is our full hands-on review of the Amerisleep AS5, including who it's genuinely right for and who should look elsewhere.

Finding a soft mattress that doesn't feel like you're sleeping in a hammock is harder than it sounds. Most ultra-soft mattresses fail in the same predictable ways: they feel heavenly for the first few minutes, then the hips sink too far, the spine curves, and you wake up stiff. The Amerisleep AS5 was designed specifically to solve this problem — to deliver the deep cushioning that side sleepers and pressure-sensitive sleepers need while preserving the spinal alignment that makes the difference between a good night and a painful one.

In this review, we break down exactly how the AS5 performs: its construction, how the softness feels in practice, how it handles heat, who it is right for, who should skip it, and how it compares in price and value to competing soft mattresses. We have tested Amerisleep's lineup extensively and believe the AS5 is among the best ultra-soft foam mattresses available today — but it is not for everyone, and we will be honest about its limitations.

Let's get into it.

Amerisleep AS5 at a Glance

Construction: What's Inside the Amerisleep AS5

Understanding how the AS5 is built helps explain why it performs the way it does — and why it's more than just "a soft mattress."

Layer 1: Bio-Pur Comfort Foam with HIVE Technology (3 inches)

The top layer of the AS5 uses Amerisleep's signature Bio-Pur foam — a plant-based material that replaces a portion of petroleum-based inputs with castor oil derivatives. This change in raw materials produces a foam with a genuinely more open-cell structure than standard memory foam. The practical benefits are real: the foam breathes better, responds more quickly to movement, and retains less heat than conventional alternatives.

Cut into this layer is Amerisleep's HIVE (Harnessing Intelligent Ventilation & Energy) technology — a proprietary hex-grid pattern of hexagonal cuts of varying widths across different zones of the mattress. The hexagons in the shoulder zone (roughly the upper third) and the hip zone are wider, creating softer, more yielding cells that allow those pressure-heavy zones to compress more deeply. The hexagons in the lumbar and leg zones are smaller, providing more resistance to keep the core of the body from sinking too far.

In practical terms: when you lie on your side on the AS5, your shoulder and hip sink into the mattress enough to offload pressure — but the lumbar area receives gentle upward support that keeps the spine from collapsing into a C-curve. This is the fundamental problem most soft mattresses fail to solve. HIVE technology, when executed at the AS5's softness level, solves it well for the right body types.

Layer 2: Affinity Foam Transition Layer with HIVE (2 inches)

Beneath the comfort layer sits a 2-inch Affinity foam layer — a denser, more responsive foam that acts as a transition between the plush comfort layer and the firm base below. This layer also incorporates HIVE patterning, reinforcing the zoned support throughout the mattress depth. The Affinity layer is what separates the AS5 from cheap soft mattresses that simply use thick, undifferentiated memory foam: it prevents the "falling through" sensation that ultra-soft sleepers often encounter.

Layer 3: Bio-Core Base Foam (7 inches)

The foundation is 7 inches of Bio-Core high-density base foam. This provides the structural integrity of the mattress — it does not compress under normal use, it resists permanent deformation over time, and it gives the softer layers above a stable platform to work from. A thick, high-density base is critical for a soft mattress because without it, the comfort layers have nothing to push back against and the result is a mattress that quickly develops body impressions.

The Cover

The AS5 ships with Amerisleep's standard stretch-knit cover. The fabric is soft, breathable, and allows the Bio-Pur foam beneath to respond naturally to your body's contours without interference. Amerisleep also offers an optional Refresh cover upgrade that incorporates phase-change cooling fibers — worth considering for sleepers who run warm.

How the AS5 Actually Feels: A Detailed Sleep-Position Breakdown

Side Sleeping on the AS5

This is where the AS5 shines without qualification. Lying on your side, the initial impression is one of deep, enveloping softness — the shoulder and hip sink in meaningfully, instantly taking pressure off those joints. But unlike a cheap soft mattress, you don't keep sinking. Within a second or two, the Bio-Pur foam firms up enough to hold you, and the HIVE support zones underneath kick in to keep the lumbar spine supported.

For sleepers who wake up with shoulder pain or hip pain from side sleeping, the AS5 can be genuinely transformative. The pressure redistribution is real — instead of the mattress pushing hard against your shoulder joint (the problem with firm mattresses for side sleepers), the joint is cushioned while the surrounding musculature is supported. Many side sleepers report the sensation as "floating" — cradled without sinking.

The sweet spot for side sleeping on the AS5 is sleepers who weigh between 100 and 170 lbs. In this weight range, the foam compresses to the right depth, and the HIVE zones provide the right counterbalancing resistance. Lighter sleepers (under 100 lbs) may find even the AS5's softness insufficient to allow proper shoulder sinkage — though this is rare. Heavier side sleepers (170 to 200 lbs) can still sleep well on the AS5, but they should be aware that the hip zone may sink a little deeper than ideal, and the AS3 is worth considering as an alternative.

Back Sleeping on the AS5

We want to be direct here: the AS5 is not a good mattress for dedicated back sleepers. At 3/10 firmness, it allows the hips to sink deeper than the neutral spine position requires, creating a slight hyperextension of the lower lumbar curve. This is the opposite of what back sleepers need. On waking, back sleepers on the AS5 often report a dull lower back ache — not severe, but persistent.

If you are a back sleeper, Amerisleep's AS2 (medium-firm) or AS3 (medium) is the appropriate choice. The AS5 was simply not engineered for this position, and no amount of trial period adjustment is likely to change the fundamental physics.

The exception: some sleepers who are primarily side sleepers but occasionally roll to their back during the night find the AS5 acceptable for those brief back-sleeping intervals. If you spend 80% of the night on your side and 20% on your back, the AS5's side-sleeping benefits likely outweigh the brief lumbar compromise in the back position.

Stomach Sleeping on the AS5

Stomach sleeping on the AS5 is not recommended, and we would advise against it. Stomach sleeping requires a firm mattress surface that holds the hips level with the rest of the body — any sinkage of the hips into the mattress creates a hyperextension of the lower back that can, over time, cause chronic lower back issues. The AS5's ultra-soft feel is the opposite of what stomach sleepers need. Amerisleep's AS1 is the product designed for that position.

Combination Sleeping on the AS5

Combination sleepers — those who shift between side, back, and stomach positions through the night — present a nuanced case for the AS5. If your primary position is side sleeping and you transition occasionally to back sleeping, the AS5 can work. The Bio-Pur foam's faster response rate compared to traditional memory foam means position changes do not require significant effort — you won't feel pinned down by slow-moving foam.

However, if you genuinely split time between side and back sleeping in significant proportions, the AS3 is the more honest recommendation. It performs better in both positions, even if it doesn't excel at side sleeping pressure relief the way the AS5 does.

Cooling and Temperature Regulation

Soft mattresses and heat retention have a complicated relationship. Softer foam compresses more deeply around your body, increasing the surface area of contact and therefore the potential for heat trapping. Traditional soft memory foam mattresses have historically been hot — a real problem for the sleepers who need them most.

Amerisleep's Bio-Pur technology directly addresses this. The open-cell structure of Bio-Pur foam allows air to move through the material rather than building up heat against your skin. In side-by-side tests against conventional soft memory foam mattresses, Bio-Pur consistently runs cooler. The HIVE hex-grid cuts in the top layer also create channels that actively promote airflow through the comfort foam.

The result is that the AS5 sleeps noticeably cooler than competing soft foam mattresses — including softer models from brands that use conventional memory foam. For the average sleeper, the AS5 is a thermally comfortable mattress.

That said, if you are a hot sleeper who runs warm even in cool rooms, you may find that any all-foam mattress retains more heat than you'd like. In that case, consider Amerisleep's Refresh cover upgrade with phase-change cooling, or explore hybrid mattress options where coil airflow is more aggressive. An all-foam mattress — even a well-designed one — will always retain more heat than a hybrid at equivalent softness levels.

Motion Isolation

The AS5 performs exceptionally well for motion isolation — which is to be expected from an ultra-soft all-foam mattress. Foam absorbs movement rather than transmitting it, and the softer the foam, the more effectively it absorbs. Couples where one partner is a restless sleeper, gets up frequently, or keeps different hours from the other partner will find the AS5 one of the quietest and most motion-isolated mattresses in its class.

In our testing, we used a standard glass-of-water test at the edge of the mattress while simulating movement on the opposite side. The AS5 showed minimal disturbance — the water barely rippled even with significant movement. For couples who prioritize undisturbed sleep, this is a genuine advantage of the AS5's soft foam construction.

Edge Support

This is the AS5's clearest weakness, and it is an honest one to acknowledge. Ultra-soft foam compresses significantly at the edges under body weight, making the perimeter of the mattress feel less stable than the center. If you sit on the edge of the AS5 to get dressed, you will sink deeply and may feel like you're about to roll off. For edge sleepers — those who use the full width of the mattress — the outer 6 to 8 inches of the AS5 feel noticeably softer and less supportive than the center.

This is not a flaw unique to the AS5. It is a physical reality of all ultra-soft all-foam mattresses. The softer the foam, the less structural resistance at the edges. If edge support is a priority for you, a firmer Amerisleep model or a hybrid with reinforced perimeter coils would be a better fit.

For typical use — lying in the center of the mattress, moving naturally through the night — edge support is rarely a meaningful issue. It only becomes relevant for edge sleepers or those who frequently sit on the bed's perimeter.

Pressure Relief: The AS5's Core Strength

Pressure relief is where the AS5 makes its case most powerfully, and it is worth spending some time explaining the mechanism.

Pressure points are areas of the body where bone structure is close to the skin surface and body weight creates concentrated force against the mattress surface. For side sleepers, the primary pressure points are the shoulder joint and the outer hip. For all sleepers, the lower back and knees can develop secondary pressure issues depending on mattress feel and position.

When pressure accumulates at these points over the course of a night, the body responds in several ways: you wake up stiff and achy, you subconsciously shift position (reducing sleep quality even if you don't fully wake), or you develop chronic musculoskeletal tension in areas that were poorly supported.

The AS5's ultra-soft Bio-Pur foam, combined with the wider HIVE hex cells at the shoulder and hip zones, is specifically engineered to redistribute this pressure. Instead of concentrating force at the shoulder joint and outer hip, the mattress distributes that weight across a larger surface area. The immediate perceptual result is the "pressure-free" feeling that side sleepers describe — a sense that the mattress is working with the body rather than resisting it.

For sleepers with diagnosed shoulder impingement, hip bursitis, IT band tightness, or sciatic discomfort that worsens at night, the AS5 is worth serious consideration. Many sleepers with these conditions find that a proper soft mattress with zoned support — not just any soft mattress — reduces or eliminates the nighttime pain component of their condition. We are not making medical claims; we are reporting what sleepers consistently describe in their feedback about this mattress.

Durability and Long-Term Performance

One of the more common concerns about ultra-soft mattresses is that they wear out faster than firmer models. Softer foam compresses more deeply with each use, raising questions about how quickly it will permanently deform under repeated loading.

This is a legitimate concern with cheap soft mattresses, but Amerisleep's Bio-Pur foam addresses it in two ways. First, the more open-cell structure of plant-based foam is inherently more resilient than conventional memory foam — it bounces back more effectively after each compression cycle, maintaining its original loft longer. Second, the high-density Bio-Core base provides a stable, non-compressible foundation that prevents the comfort layers from having nowhere to recover to.

Amerisleep backs the AS5 with a 20-year warranty — double the industry standard of 10 years and nearly double what most competing brands offer. The warranty covers sagging or body impressions greater than 3/4 inch in depth, which is a stricter threshold than the 1-inch standard used by many competitors. This means you can legitimately claim warranty service earlier, before the degradation reaches a point of significant discomfort.

In practice, a well-maintained AS5 used with an appropriate foundation (solid platform or slatted base with slats no more than 3 inches apart) should remain in good condition for 8 to 12 years. This is on par with or better than competing soft foam mattresses at similar or higher price points.

Unboxing and Setup

The AS5 ships compressed and rolled in a box — the standard delivery format for direct-to-consumer mattresses. The box can be moved by one person, though it is heavy (a Queen weighs approximately 80 lbs in its compressed form). Setup is straightforward: move the box to your bedroom, unbox the rolled mattress, unroll it on your foundation, and cut the plastic wrapping. The mattress will begin expanding immediately and typically reaches full height within a few hours.

Amerisleep recommends waiting 24 hours before sleeping on the mattress to allow it to fully decompress and for any residual off-gassing odor from the foam manufacturing process to dissipate. In our experience, the off-gassing from Bio-Pur foam is mild and fades quickly — far less noticeable than conventional memory foam products. The plant-based composition of Bio-Pur foam contributes to a cleaner smell profile.

No tools are required for setup. White-glove delivery and old mattress removal are available as optional add-ons through Amerisleep's checkout process.

Price and Value: Is the AS5 Worth $1,399?

The Amerisleep AS5 is priced at $1,399 for a Queen, putting it in the middle of the premium direct-to-consumer mattress range. To evaluate whether that price is justified, it helps to look at what you're actually buying:

• Proprietary Bio-Pur plant-based foam (not standard polyfoam)
• HIVE zoned support technology (not generic foam layers)
• 20-year warranty (vs 10-year industry standard)
• 100-night trial with free returns
• Free shipping both ways

Competing ultra-soft mattresses in the same price range — brands like Saatva's softer models or Bear's plush options — often carry 10-year warranties and use more conventional foam construction. The AS5's material quality and warranty coverage represent genuine differentiation, not just marketing language.

Amerisleep also runs regular promotional pricing. It is common to find the AS5 discounted by $100 to $300 during holiday periods and seasonal sales. If you are not in a rush, waiting for a promotion can meaningfully reduce the effective price. However, even at full price of $1,399, the value proposition for a 20-year warranted, plant-based foam mattress specifically engineered for side sleepers is strong.

For context: the average American replaces their mattress every 8 years. If the AS5 lasts 10 years at full comfort — a conservative estimate given the warranty and material quality — you are spending approximately $140 per year for a sleep surface. At 8 hours of sleep per night, that works out to less than $0.05 per hour of sleep. This is the correct frame for evaluating mattress value.

How the AS5 Compares to Other Amerisleep Models

If you are unsure whether the AS5 or the AS4 is right for you, consider your weight and your primary sleep complaints. If you are under 150 lbs or have notable shoulder or hip pressure pain, the AS5 is the better call. If you are between 150 and 200 lbs and want softness without worrying about excessive sinkage, the AS4 may be the safer middle ground.

Trial Period and Return Policy

Amerisleep offers a 100-night sleep trial on all their mattresses, including the AS5. During those 100 nights, you can return the mattress for any reason and receive a full refund. Amerisleep arranges the pickup at no cost to you — you do not need to repackage or transport the mattress yourself.

A word of practical advice: sleep takes time to adjust. If you have been sleeping on a firm mattress for years and switch to the AS5, the first few nights may feel strange — not because the mattress is wrong for you, but because your body has adapted to a different sleep surface. Give the AS5 three to four weeks before making a decision. Most sleepers who stick with the trial find that their body adapts and the softness that felt unusual initially becomes the new normal.

The 20-year warranty activates after the trial period ends (if you keep the mattress). It covers sagging or body impressions deeper than 3/4 inch, physical defects in materials, and issues with the cover. Normal wear and tear is not covered, nor is damage from improper use (such as using a foundation with overly wide slats).

What We Like and What We Don't

What we like about the Amerisleep AS5:

• Genuine pressure relief for shoulder and hip pain in side sleepers
• HIVE technology prevents the "hammock" sinking problem of cheap soft mattresses
• Bio-Pur foam sleeps cooler than competing soft foam alternatives
• 20-year warranty is among the best in the industry at any firmness level
• Motion isolation is excellent — ideal for couples with different sleep schedules
• Faster foam response than traditional memory foam — easier to change positions
• Clean, mild off-gassing due to plant-based foam composition

What we don't like about the Amerisleep AS5:

• Not suitable for back or stomach sleepers — the firmness range is specific
• Edge support is soft and unstable, as expected from ultra-soft all-foam construction
• Not recommended for sleepers over 200 lbs due to excess sinkage
• No hybrid option at this softness level — coil airflow would benefit warm sleepers
• Full price of $1,399 is a meaningful investment, though value is justified

Final Verdict: Who Should Buy the Amerisleep AS5?

The Amerisleep AS5 is a specialized mattress built for a specific group of sleepers — and for that group, it is among the best options available in the direct-to-consumer market.

The 100-night trial removes virtually all the risk from this decision. If you think the AS5 might be right for you, there is little to lose in trying it — and potentially a great deal of better sleep to gain.

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