Amerisleep AS4 Review

Last Updated: April, 2023

Please Note: This Post Contains Affiliate Links

Amerisleep is a reputable mattress company popular for producing some of the best mattresses in the industry. The Amerisleep line comprises five mattress models, AS1 to AS5, in order of their firmness level from the firmest to the softest. The AS4 Mattress falls on the medium soft spot, making it ideal for side sleepers needing more plush cushioning combined with some body support. 

The mattress is designed with eco-friendly materials, which also helps uphold Amerisleep's motto, "Better sleep for a better tomorrow." If you're unsure whether AS4 is the right mattress for your needs, then this Amerisleep AS4 Mattress Review is here to point you in the right direction. 


Amerisleep AS4 mattress review - Summary

As Amerisleep's flagship model, this medium soft mattress is a great pick for fanatics of soft mattresses, especially side sleepers, thanks to its world-class pressure relief. The Bio-Pur foam and the HIVE transition layer offer zoned support to your feet, head, and back while providing incredibly soft comfort for your shoulders and hips. 

What We Like

  • Breathable Refresh Cooling Cover and proprietary Bio Pur Foam helps keep you cool
  • High-density Bio Core Foam provides the mattress with overall structural support 
  • Affinity Layer is fitted with surface modification technology that provides great pressure relief
  • Ideal for light and average weight sleepers
  • Compatible with all kinds of adjustable bases

What We Don't Like

  • May cause a stomach sleeper spinal misalignment

Amerisleep  is running a sale on their mattresses, active today June 17, 2024!

Material Construction

As already mentioned, this is an all-foam mattress. However, what distinguishes it from an ordinary memory foam mattress is the construction and nature of the materials making up its layers. Here, we will inspect this Amerisleep AS4 Mattress layer by layer to see what it's made of. 


Amerisleep As4 - cover

Amerisleep is running a sale on their mattresses, active today June 17, 2024!

Like all the Amerisleep Mattresses, the AS4 Mattress has Refresh Cooling Cover. The cover is super breathable, thanks to the special technology it's fitted with that converts body heat to infrared energy. Scientific research shows that infrared energy helps boost sleep quality, athletic recovery, and blood circulation. 

Comfort Layers

Unlike other memory foam mattresses in the market, this AS4 Model's comfort layer is 4 inches thick. The layer consists of the plant-based Bio-Pur Foam that's not only pressure relieving but also super responsive. Compared to ordinary memory foam, the Bio-Pur Foam is CertiPur-US certified, meaning it is low in volatile organic compounds. 

Beneath the top layer within the comfort zone is the 1-inch HIVE transition layer. Since it is zoned, this layer gives the mattress different firmness levels across the sleep surface. The zoning helps further relieve pressure around the hips and shoulders. However, it feels firmer around the feet, back, and head providing you with more support.

Support Layer

At the very bottom is the 7-inch Bio-Core foam support layer responsible for the structural support of the entire mattress. Like the Bio-Pur foam, the Bio-Core material is eco-friendly. The base layer is super resilient and, therefore, can't sag easily even after decades of use.

Amerisleep AS4 Performance

Now that you know the components making up this Amerisleep AS4 Mattress, let's look at how their performance influences your sleep comfort.

Temperature Regulation

Unlike traditional memory foam mattresses, the open-cell structure within its comfort layers minimizes heat retention to keep you cool during hot nights. Its specially designed breathable cover helps hot sleepers to stay cool throughout the night. Also, the cool-to-the-touch effect of the breathable cover gives the AS4 Mattress a cool sleeping surface that helps shield you against night sweats. However, if you frequently find that you overheat at night, you may want to go for the best cooling mattress.

Pressure Relief

Amerisleep AS4 - pressure relief

Amerisleep is running a sale on their mattresses, active today June 17, 2024!

With a firmness scale of 6.0/10—lower than the industry standard 6.5/10 for a medium firm mattress—this Amerisleep AS4 Mattress qualifies as a medium soft mattress. And, thanks to the 4-inch thick layer of Bio-Pur Foam, this mattress offers great pressure relief, especially to combination sleepers and light and average weight side sleepers. 

The soft memory foam layer also makes this Amerisleep AS4 Mattress snuggly and super comfy for restorative sleep. Its unique design helps distribute body weight equally on the sleep surface, which excellently helps in relieving the pressure points.

Motion Transfer 

Motion transfer is critical for couples, co-sleepers, or people who often sleep with their pets. Since this Amerisleep Mattress is a memory foam model, there is a minimal disturbance between the sleepers. Generally, its memory foam construction absorbs motion vibrations generated by tossing and turning co-sleepers, ensuring each person sleeps soundly. Couples looking for disruption-free mattresses should give strong consideration to AS4 memory foam beds.

Edge Support

Most memory foam mattresses are known to have poor edge support. However, this Amerisleep AS4 Mattress performs well for a memory foam model in this department. Arguably, this is one of the best mattresses for partners with small beds who love memory foam sleep products. Its decent edge support allows you to sleep comfortably, even on the mattress' edge, without risking falling to the ground. 

The edge support is also sturdy enough for occasional sitting. Though more supportive than most memory foam brands, occasional sitting may leave some indent on the foam. Also, sitting on a single spot over prolonged periods may break the sides of your bed. We recommend you keep the occasional sitting at the edge at a minimum to maintain the mattress' longevity. 


This Amerisleep AS4 Mattress does not make noise. Since its construction is primarily memory foam, you don't have to worry about squeaking springs. And with its responsiveness, you can move easily on the surface. 

Off Gassing

The Amerisleep AS4 Mattress has some slight off-gassing that lasts a few hours before completely dissipating. And since the mattress is made of environmentally sustainable materials, the off-gassing is very low in VOCs.


As previously mentioned, this Amerisleep Mattress is super durable, thanks to its resilient base layer. It also comes with a warranty of 20 years which ensures it lasts longer than an average memory foam mattress.

How the Amerisleep AS4 Feels Like

Firmness and feel are major metrics to consider when shopping for any mattress, including this Amerisleep Mattress. And as already established, AS4 is a medium soft bed. Like other mattresses in the Amerisleep line, the AS4 bears a balanced foam feel responsible for the mattress' responsiveness. 

Thanks to the rapid response time of its thick comfort layer, the ASS4 Memory Foam Mattress excels in relieving pressure points. Lying on it immediately exhibits nice body contouring, unlike the stuck-in-the-mud feeling you'll get when sleeping on a traditional memory foam mattress. 

Sleeping Positions and Body Types

Though the construction and design of the AS4 Mattress primarily target side and combination sleepers, it can also accommodate other sleeping positions depending on the sleeper's weight. Here, we'll look at what this Amerisleep Mattress offers sleepers for each position. 

Side Sleepers

The Amerisleep AS4 Mattress is primarily ideal for side sleeping. This is thanks to its thick conforming Bio-Pur layer that allows your body to sink into the surface just enough for maximum contouring and pressure relief. And since this is a medium soft mattress, lightweight side sleepers need not worry about pressure building up around their shoulders, hips, and knees.

If you're an average weight side sleeper, this mattress is the right choice. Buyers who prefer firmer mattress surfaces than the AS4 should go for the AS3 Hybrid. Average weight side sleepers weighing close to 200 lbs will love the comfortable feel of the Amerisleep AS5 hybrid model. 

Generally, heavyweight sleepers need firmer mattresses that provide enough support. So, heavyweight side sleepers should opt for a medium to medium soft bed like this AS4 since insufficient support may cause spinal misalignment. 

Stomach Sleepers

Though more responsive than average memory foam beds, the Amerisleep AS4 isn't a supportive mattress ideal for stomach sleepers. In fact, as a general rule of thumb, a great mattress ideal for a side sleeper isn't ideal for stomach sleepers mainly because of its soft surface. 

To avoid spinal misalignment, lightweight stomach sleepers should opt for medium firm Amerisleep models that provide more pressure relief than support, like AS3. On the other hand, average stomach sleepers are more likely to sink deeper on this mattress. We recommend they opt for models with a firmer feel, such as the AS2, which ensures the rest of the body aligns properly with the hips. 

If you're a heavyweight stomach sleeper, you may want to opt for the AS1, which is a great pick for buyers with body weight exceeding 230 lbs because of the maximum support it provides the body. This is evident in its Bio-Core® base layer, which offers the mattress more structural support and doesn't sag easily under any extra weight.

Back Sleepers

Since it's on the medium soft side, the Amerisleep AS4 Mattress isn't suitable for back sleepers weighing more than 230 lbs. 

Heavyweight back sleepers weighing more than 230 lbs are better off seeking mattresses that provide more support, like the AS1 and AS2, depending on their needs. The AS1 and AS2 models are designed to provide maximum support and minimize excessive sinkage so you don't feel stuck on the sleep surface. 

Average weight back sleepers weighing approximately 170 lbs or more are better suited for firmer mattresses like the AS2. The AS2 Mattress does quite splendidly in distributing weight equally across the surface while contouring your curves and maintaining support.

Combination Sleepers

Generally, a great mattress for a combo sleeper is one that doesn't make them feel trapped in the sleep surface. Combination sleepers who often switch positions between their back and stomach may not find this bed quite comfortable. However, its medium-soft profile makes it suitable for combo sleepers who predominantly sleep on their side.

Warranty, Shipping, Sleep Trial, and Returns

Like most mattresses in the mattress industry, all Amerisleep Mattresses have warranties, free shipping, risk-free trials, and return policies as outlined below. 


The Amerisleep AS4 Mattress has an incredibly extensive warranty of 20 years, slightly higher than the industry standard. Note that the 20-year warranty is divided into two parts. 

The Amerisleep company will fully cover this Amerisleep AS4 Mattress for the first ten years. That means if your mattress has any manufacturing problem, the company will replace or repair it for free. During the second 10 years of the warranty, you'll be charged a certain percentage for any repairs and replacement.

Sleep Trial

All Amerisleep Mattresses come with a 100-night risk-free sleep trial, including AS4. This gives your body enough time to adjust to the bed and helps you decide whether or not it meets your required comfort preferences. If you don't like the mattress, you can return it for a full refund.


The Amerisleep AS4 Mattress ships for free but only to addresses within the contiguous U.S. Also, it comes as a compressed mattress packaged in a box via FedEx courier. Usually, it takes about a week from when you place and pay for your order before you get the mattress. 

Shipping is also available for addresses outside the contiguous U.S. but at a fee. Buyers outside the contiguous U.S. should contact the Amerisleep company about shipping fee information and timelines.

Return Policy

If this mattress doesn't meet your desired needs, you can return it but within the 100-night sleep trial. All you need to do is reach out to the company and give them your mattress order number. 

Return is also free, so just place your unwanted mattress on the curb for a pick-up. You'll then get a full refund within 14 business days. But if you want to change the model for a much firmer or softer mattress, you can also reach out to the company for an exchange.

Closing Thoughts

Hopefully, the insights in this Amerisleep AS4 Mattress Review will help you choose the right mattress. As previously mentioned, the company produces among the best memory foam mattresses in the industry, and if you're looking for high-quality mattresses for side sleeping, you can never go wrong with Amerisleep's soft models. With its incredible durability, world-class performance, and long warranty period, the AS4 is undoubtedly a mattress worth every penny of your investment. 

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