Amerisleep AS4 Mattress Review

Headshot - Serena Scheide

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Bare Amerisleep AS4 mattress situated in a stylish bedroom on light gray foundation.
We evaluate mattresses across 8 key categories, providing an overall rating for easy comparison. For more details on our review process, read about how we test by clicking the question mark below.


Pressure Relief
Motion Isolation
Edge Support
Ease of Movement

Our Verdict

The AS4 is not only an excellent option for side sleepers, combo sleepers, lightweight sleepers, and those who sleep hot, but it is also a great choice for eco-conscious shoppers. Thanks to its plant-based foams, the AS4 is a sustainable and environmentally friendly option that provides adequate support while relieving pressure points. However, for those who prefer a firmer mattress or are back or stomach sleepers, the Amerisleep AS1 or AS2 would be a better choice.


  • Exceptional pressure relief, great for pain relief
  • Zoned construction for targeted comfort and support
  • Sustainable and eco-friendly
  • Cooling technologies help hot sleepers stay cool throughout the night


  • Not enough support for stomach sleepers
  • Not ideal for those who prefer a firmer mattress
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Product Details

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Memory Foam

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Vector image of a half moon, stars and zzz, referencing mattress sleep trial


Vector image of a shield with a tick, referencing warranty


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Free Standard

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Amerisleep is known for having some of the best mattresses on the market. While the brand predominantly focuses on memory foam mattresses, the lineup also includes latex and hybrid options. Ranging from the very firm AS1, to the ultra soft Amerisleep AS5, the brand caters to all body types and sleep positions. So, which one is right for you? In this review, we take a look at the AS4, a medium-soft mattress best suited to side sleepers who crave relief from painful pressure points.

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Amerisleep AS4 mattress construction

The AS4 mattress boasts a 12” profile with an Ultra-breathable cover. The mattress cover has a soft, stretchy feel and is cool to the touch. A huge bonus is you can unzip, remove the cover, and machine wash it. This is really great if you have children or pets that share the bed with you. We have tested many mattresses that unzip but not many that you can machine wash. This was a huge plus for us!

The top layer of foam has a very unique pressure relieving yet supportive feel. It features a plant-based, open-celled structure foam called Bio-Pur. This eco-friendly foam has a slight memory foam feel but doesn’t have the same sluggish responsivenes.

Next up, the HIVE transition layer which includes zoned construction. We have found through testing many mattresses that the ones designed with different zones are slightly more supportive. This foam layer is divided into 5 different sections to give you support where you need it most. At the same time, the foam provides extra cushion through the hips and shoulders, where you often find pressure build-up, this is especially true for side sleepers.

The Bio-Core makes up the base layer. This layer is a dense, durable foam that offers long-lasting durability.

Amerisleep AS4 Memory Foam Layers

The Making of the Memory Foam

All of the Amerisleep beds are made with CertiPUR-US certified foam. This means the foams will not off-gas nasty chemicals into the air, such as ozone depleters, formaldehyde, or heavy metals. We have unboxed many mattresses, some giving off a foam smell that lasted for days and some with very little smell. The Amerisleep AS4 had some slight off-gassing but it only lasted for a few hours. 

Another feature that sets Amerisleep apart is the use of plant-based oils instead of petroleum. This makes their foam more environmentally friendly than traditional memory foam mattresses, using zero emissions and reducing the VOCs in the mattress. The Amerisleep mattresses are also Made in the USA.

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Amerisleep AS4 Firmness & Feel

On the Amerisleep website, the AS5 is listed as the softest of the mattress models. Having tested a few other Amerisleep mattresses, including the AS3, AS3 hybrid, and the Amerisleep AS5, we were surprised to find the AS4 felt softer than the AS5. That being said, we rate the AS4 at a 4 on the firmness scale with 1 being the softest and 10 being the firmest. 

The AS4 is an excellent choice for all side sleepers and those with chronic pain issues. The Bio-Pur foam has a rapid response time, bouncing back quickly to relieve pressure and prevent heat build-up. When you lay down on the AS4 you will immediately experience some nice contouring but you won’t be left with that stuck-in-the-mud feeling associated with traditional memory foam. This is especially useful for combination sleepers that tend to change positions a lot. 

The AS4 is intended for side and combination sleepers. It is not designed for strict stomach sleepers and back sleepers. Stomach sleepers are best served with a medium-firm to firm mattress. Mattresses in this firmness range should help keep your hips lifted and prevent placing pressure on the low back. This helps to reduce, or in some cases, eliminate back pain altogether. 

If you are a back sleeper we recommend you check out the Amerisleep AS2, while stomach sleepers would best be matched with the Amerisleep AS1. The AS2 is available in memory foam or hybrid while the AS1 is memory foam only.

Firmness Scale 1-10 highlights a 4.0 or medium soft firmness.
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Medium to Medium-Firm


Mattress Performance

Does the AS4 Sleep Cool?

In general, all of the Amerisleep mattresses have excellent cooling benefits and the AS4 was no exception. It did a great job of keeping us from feeling hot all night long. Many mattresses say they sleep cool and really only sleep neutral. 

The open-cell foam is ultra-breathable and the fact that you don’t sink very far into the mattress helps to keep you cool. That being said, your mattress is only as cool as your protector. If you put on a cheap protector that is not breathable you will not get the cooling benefits of the Amerisleep mattress. Check out Amerisleep’s waterproof mattress protector or browse these Amazon top sellers.

Motion Transfer

Motion transfer is particularly important for couples or anyone sleeping with pets or kids in your bed. The Amerisleep AS4 did great in the motion transfer category! If you tend to wake easily due to your partner moving throughout the night, the Amerisleep AS4 would be a good choice for you. I was not surprised with all of the layers of foam and the dense foam core, it was bound to be pretty good.

Edge Support

Edge support is a category that could be very important to couples sleeping on a smaller mattress. If edge support is lacking you could feel like you’re falling off the bed as you move to the outer edges. You might even feel the bed frame if the mattress compresses too much when you are lying near the edge. Overall, the AS4 has decent edge support. I did not feel like I was going to fall off when laying on the edge of the bed. I also felt pretty supported when sitting on the edge of the bed.

Amerisleep AS4 Testing Out The Edge Support
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Amerisleep Mattress Purchase Details

Sleep Trial

Like most bed in a box companies, Amerisleep offers a 100-night sleep trial period. This is pretty standard for the mattress industry along with one stipulation: you must keep it for at least 30 days before initiating a return. You will need time to adjust to this mattress especially if you have been sleeping on something that is too soft or sagging.


Amerisleep offers a 20-year warranty on all of their mattresses. 20 years is more than the industry standard. Amerisleep will fully cover the mattress for the first 10 years and then it is prorated. Like most companies, you must be the original owner to benefit from the warranty.

Shipping & Delivery

Amerisleep offers free shipping and returns. They use eco-friendly packaging and it is quickly shipped via FedEx. If you do end up not loving the mattress they will help you schedule a donation or recycling pickup for the unwanted mattress.

Prices, Bed Sizes, & Weights

A Queen Amerisleep AS4 is priced at $1749 before discount. Amerisleep frequently runs specials, allowing you to rack up on the savings. See our coupon below or visit our mattress deals page for the most up-to-date discounts.





38″ x 74″ x 12″


Twin XL

38″ x 80″ x 12″



54″ x 75″ x 12″



60″ x 80″ x 12″



76″ x 80″ x 12″


California King

72″ x 84″ x 12″


Split King

38″ x 80″ x 12″ (x2)


*Prices may be subject to change.

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Choosing a compatible bed frame or foundation

Purchasing a mattress is a big investment! Most of us will keep our mattress for a minimum of 5-10 years, during which, approximately ⅓ of our life will be spent in bed. That being said, you’re going to want to protect your investment. 

Purchasing a suitable bed base or foundation is not only crucial to getting the best sleep, but it also ensures your warranty remains valid. Most mattress warranties state that improper support for your mattress can void your warranty so you’ll want to make sure to read the fine print. 

Amerisleep states their mattresses should be used on solid, non-spring foundations, including platform bed frames and adjustable bases. If using a box spring you are required to place a minimum three-quarter inch moisture resistant piece of plywood over the entirety of the box spring. Slatted frames are also acceptable but slats should be no greater than 3” apart. 

Check out Amerisleep’s bed frames and bases or browse these top-selling bed frames on Amazon.

Amerisleep AS4 Sleeping On Side

Amerisleep AS4 Best Mattress Awards

Amerisleep AS4 Mattress Review Conclusion

Amerisleep is a great company that makes quality mattresses. What makes them stand out is the unique pressure relief, support, and cool feel of their foam. The AS4 could be great for almost all sleep positions except for stomach sleepers and/or those who are looking for a firm mattress. 

That being said, the Amerisleep AS4 is an especially good choice for side sleepers and combo sleepers. Lightweight sleepers who struggle to get enough pressure relief should also be especially pleased. And if you sleep hot, this could also be a great mattress choice for you! Zoned construction provided adequate support while melting away pressure points.

The great thing about Amerisleep is they offer a wide range of mattresses with different firmness levels so you are bound to find what you’re looking for. If you know you prefer a firmer mattress or you are more of a back or stomach sleeper, then we suggest checking out the AS1 or the AS2. If you’re still undecided on the right firmness, check out Amerisleep’s chat feature, where you can speak directly with a sleep specialist.

Searching for the perfect mattress? Let ASL Reviews help, our in-depth mattress reviews can help you decide which mattress is right for you.

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