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AS4

Risk-free, 100-night trial

20-year warranty

Free shipping & returns

Made in USA

Non-toxic & Fiberglass-Free

AS4

Experience cloud-like comfort with the medium-soft AS4. Designed with a deeper top layer of pressure-relieving foam, our AS4 offers extra cushion for side and combo sleepers.

Size

Enhanced Cooling

Refresh Cooling

Refresh Cooling Technology

INCLUDED

Sleep up to 7 degrees cooler throughout the night with our incredible heat-wicking Refresh Cover - included free on every AS4.

Add a base

Bed, frame, platform, whatever you want to call it: If you're also hunting for the perfect mattress support, we've got some winners to choose from.

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  • Inc. logo

    Taking The Mattress
    Industry by Storm

  • Forbes logo

    Masterpieces of Midnight
    Melatonin Replenishment

  • icon of 4.5 stars

    15,000+ Reviews
    Average of 4.7 stars1

  • USA TODAY logo

    Sleep Education Over
    Superficial Satisfaction

  • Adweek logo

    Experience First,
    Sales Second

Better sleep through better design

  • Sleep Cooler

  • Comfort You Will Love

  • Designed to Enhance Sleep

  • Alleviates Pressure Points

  • Eco-Friendly Production

Cooler and more breathable

The surface you sleep on is incredibly important to your comfort. That's why we developed the Refresh Cover for our mattresses.

Because it's made from a fiber with extremely high energy transfer capabilities, the Refresh Cover draws heat from your skin for a delightfully cool-to-the-touch feel. On average, your sleeping surface will stay 7 degrees cooler over an eight-hour night of rest.*

Plus, our plant-based Bio-Pur material keeps you cool all night. Its open-cell design allows more air to circulate than traditional foam — and more airflow means cooler sleep, less sweating, and no more tossing and turning.

*Compared to a traditional 100% polyester cover.

Improve circulation

Along with keeping you cool, the Refresh Cover also supports improved daily performance and energy. This scientifically engineered fabric uses minerals to help convert your natural body heat into far infrared energy.

Why far infrared? This type of energy increases blood circulation to help speed up muscle recovery and improve quality of sleep. Plus, according to peer-reviewed medical studies, far infrared exposure may offer even more health benefits than we even know about yet!*

*Source: Journal of Photonics & Lasers in Medicine

Stays cool all night

Our plant-based Bio-Pur® material keeps you cool all night. It features an open-cell design that allows more air to escape than traditional foam.

Moon icon

Open-cell design wicks away warm air

Wind icon

More breathable than traditional foam

Experience Bio-Pur®:
Eco-Friendly, Cooler Memory Foam

Bio-Pur® is the perfect answer to a better bed. Available in every Amerisleep mattress, we engineered Bio-Pur® to deliver cooling comfort, responsive support, and healthier sleep.

Memory foam lovers say Bio-Pur® is a huge upgrade, while critics admit it solves all the problems of traditional memory foam. Plus, since our beginnings in 2009, we've proudly manufactured Bio-Pur® in the USA.

Bio-Pur® vs Traditional Memory Foam

Breathable & Cooling

Bio-Pur®'s large, open-cell structure has a few distinct advantages:

  • Allows air to flow freely
  • Prevents heat build-up
  • Perfect for hot sleepers

Responsive & Supportive

Unlike traditional memory foam, Bio-Pur® has a rapid response time that:

  • Relieves painful pressure points
  • Prevents heat build-up
  • Bounces back in just seconds

Eco-Friendly Materials

Featuring renewable plant-based oils, Bio-Pur® helps us:

  • Minimize use of non-renewable resources
  • Prevents heat build-up
  • Produce products that are better for you and the planet

A Healthier Sleep

The surface you sleep on is important. That’s why Bio-Pur® is:

  • CertiPUR-US® certified & low in VOCs
  • Resistant to dust mites, mold, and mildew & made without harsh chemicals

See why our customers love Bio-Pur®

So ideal in so many ways

Our king-size Amerisleep is the most comfortable, movable, breathable, restful mattress we've ever slept on, and would not consider buying anything else in the future. Thank you, Amerisleep!

Bryan Martin

Dearborn, MI

Perfectly Balanced

I hit the purchase button and wasn't disappointed. All the good things you've read - breathable, soft yet supportive, environmentally friendly, clean, effective - are true. This is the best...
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Franklin

Nebraska

Sleeps Cool and is Very Comfortable

We upgraded to a king bed and transitioned to foam from inner spring. My wife and I sleep so much better. We move a lot in the night, and our...
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Tom

Fairfax, VA

I would recommend this mattress to anyone

This king size mattress is GREAT!! My other king is now in the guest room and I'm enjoying my cool, comfortable Amerisleep mattress.

Linda

Austin, TX

So with the investment. Wish I made the move earlier

So good for those with restless sleepers. My partner is finally getting rest. And I who was usually running hot and cool and comfortable.

Conor

Ontario, Canada

Excellent Product, Excellent Sleep

This is an excellent mattress. I was a bit worried getting the Amerisleep, as I am primarily a side sleeper, but I am getting the best sleep of my life...
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Nick

Colorado

Cooler, better nights sleep

We were very nervous to buy this mattress without seeing it first. It is really comfortable. I used to get too hot every night with my old mattress but this...
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Kelandra

Lockport, NY

I love my new mattress!

We ordered the first twin xl for our master bedroom adjustable bed. My husband wanted a new mattress for his side. I liked mine so we just got one. He...
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LK

Daytona Beach, FL

I look forward to bedtime : )

I have been looking at mattresses for about 8 years, doing research in town (nothing was working for me) so I started to do research on the internet. I have...
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Marilee

Roy, UT

I would buy from Amerisleep again

Primary bed. Bought this for the cooling aspect and hip issues.

Mike

Sterling, CO

This is our second mattress and we love both

This is a second bed that is used often when having trouble sleeping. We have been using our first mattress for several years and love it. This new mattress did...
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David

Charleston, SC

Relieves pain & pressure points

Our Bio-Pur® comfort layer contours to your body and relieves pain-causing pressure points. But it also bounces back fast, so you never feel “stuck” if you move around at night.

Zoned comfort icon

Soothing pressure point relief

Pressure point icon

More responsive than traditional foam

Crafted for lasting comfort

We make our mattresses here in America with the highest quality craftsmanship. They’re built to last and backed by a two-decade warranty.

Warranty icon

Industry-leading 20-year warranty

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Won’t sag or develop soft spots

Made with side sleepers in mind

Our medium-soft mattress offers plush comfort with targeted support that helps you sleep your best.

Amerisleep AS1 mattress coverAmerisleep AS1 mattress layers

Ultra-Breathable Comfort

Our soft and ultra-breathable covers help prevent overheating, so you can sleep your best each night.

Stays Cool & Never Feels “Stuck”

Bio-Pur®'s open-cell design keeps you cooler than traditional foam. It also contours to your body to relieve pressure points and bounces back fast, so you won't feel “stuck”.

Targeted Pressure-Relief System

Our HIVE® transition layer provides targeted support and pressure relief so you can sleep in perfect alignment. It gives your head, back, and legs more support, and your shoulders and hips more cushion.

Durable Support for Decades

The Bio-Core® base layer gives you durable support that lasts for decades. It won't sag or develop soft spots over time. (And we prove it with our 20-year warranty.)

Sleep in perfect alignment

Our HIVE® transition layer gives your body targeted support to ease tension and help you sleep in perfect alignment. It provides added support under your head, back, and legs. And it gives your shoulders and hips extra cushion. We've also designed HIVE® to reduce pain-causing pressure points.

Enjoy deeper sleep and more daily energy. Try the AS4 for 100 nights.

100 Night Trial
Risk-free, 100-night trial
with free shipping & returns

Specifications

  • Twin
    38" W x 74" L x 12" H
  • Twin XL
    38" W x 80" L x 12" H
  • Full
    54" W x 75" L x 12" H
  • Queen
    60" W x 80" L x 12" H
  • King
    76" W x 80" L x 12" H
  • Cal King
    72" W x 84" L x 12" H
  • Split King
    38" W x 80" L x 12" H (x2)

Amerisleep Mattresses come with free shipping within the continental US. We ship our mattresses direct to your home and compressed in an eco-friendly box using FedEx. And in most cases, they arrive in two weeks or less.

Please note: All our products ship separately, so if you’ve ordered a foundation, base, sheets, or any other sleep accessories to go with your new mattress, they may arrive sooner or later than your Amerisleep mattress. But don’t worry, shipping is always free.

Amerisleep mattresses are backed by an industry-leading 20-year warranty. For the first 10 years, we will replace your mattress if you encounter any defects, including sagging greater than 1.5” inches. And for the second 10 years, we will offer you a prorated replacement.

Our mattresses are compatible with a variety of bed frames and bases.

Mattress Foundations
Our memory foam and hybrid mattresses are best supported on solid or slatted mattress foundations. We offer a variety of bed bases which are all compatible with our mattresses. Non-Amerisleep foundations, however, should have slats no more than 2.75 inches apart.

Platform Beds
Platform beds have a solid or slatted base, so they can provide proper support for our mattresses. If you have a platform bed with large gaps between slats that was not designed by Amerisleep, we suggest buying extra slats or a bunkie board to create a sturdier surface for your mattress and meet warranty guidelines.

Adjustable Bed Frames
Our memory foam mattresses work well with adjustable bed frames. They’re adaptable and flexible, so they can move with the base without becoming damaged or worn. We even sell two adjustable bed frames to pair with our beds: the Amerisleep Adjustable Bed and the Amerisleep Adjustable Bed+.

While our mattresses can work with most bed frames and foundations, it’s not compatible with absolutely every type of mattress support — namely box springs.

Box Springs
Box springs are best paired with innerspring mattresses, and since innerspring beds were the most common for many years, a lot of us have box springs at home. Box springs contain coils within and as a result, are bouncy. Beds with foam layers can experience premature wear, tear, and unexpected damage when paired with one of these because they do not offer the even, sturdy support foam beds need.

If you intend to use an existing bed frame, please confirm dimensions & assembly options for your bedframe to ensure compatibility.

Upgrade your mattress with our complete sleep system

Amerisleep pillow

Go ahead and relax

Shop our lineup of pillows engineered for better head and neck support.

Browse Pillows
Amerisleep bedding

Wrap yourself in luxury

Explore our suite of bedding options designed for exceptional softness and comfort.

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See what our satisfied sleepers have to say

Be the first to let us know what you think!

Frequently Asked Questions

Yes, our AS4 mattress is supportive from its top layer of Bio-Pur® foam to its middle and base foams:

  • The comfort layer of Bio-Pur® responds to your every movement to limit sinkage, keeping your spine from bowing so far into the mattress that you misalign your back.
  • The middle layer is Affinity foam with HIVE® technology, which features five support zones so that it’s soft where you want it and firm where you need it. The head, back, and feet areas have a less flexible feel to create more support.
  • The base layer is Bio-Core® foam, a material that’s so durable and sag-resistant that it’s the main reason why we can offer a 20-year warranty.

Medium-soft mattresses are excellent for side sleepers who want a soft mattress that isn’t too soft. They can sink into the mattress just enough to appreciate its cradling cushion but won’t sink so far that they develop back pain.

A medium soft mattress is also a good choice for people under 130 pounds. Smaller sleepers often don’t place enough pressure on their mattress’s surface to experience full-body cushion and pain relief on firmer mattresses.

Yes, the AS4 mattress promotes a cool sleeping surface with its temperature-regulating cover and its airy top foam layer. The entire mattress is covered with a soft, breathable fabric to ensure air flows through the bed and wicks away accumulated heat. The top layer of Bio-Pur® foam has an open-cell structure to promote heat dispersion.

Our AS4 mattress can be paired with almost any solid or slatted base. You can use a wooden mattress foundation, a panel bed frame, a platform bed, and an adjustable bed base. If you use a slatted surface, make certain the slats are at least 0.75 inches thick and no more than 3 inches apart.

Do not place the AS4 or any of our mattresses directly on top of a box spring. A box spring cannot provide a consistently even surface and will leave gaps that allow a mattress to sag prematurely.

A CertiPUR-US® certification means that a third-party organization has overseen our foam production process and deemed the mattress’s materials safe. A CertiPUR-US®-approved mattress is produced without:

  • Formaldehyde
  • Mercury, lead, and other heavy metals
  • Ozone depleters
  • PBDEs, TDCPP or TCEP flame retardants

A CertiPUR-US® certified mattress also has low amounts of volatile organic compounds (VOCs). Fewer VOCs means the mattress is less likely to off-gas, which is the process behind a funky and lingering “new mattress smell.”

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