Casper One vs. Amerisleep AS3 Mattress Comparison

Overall Rating

8.2

Casper One

Bottom Line

A medium-firm mattress with a three-layer foam construction for maximum support.

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Full Mattress Review

VS

Overall Rating

7.7

Amerisleep AS3

Bottom Line

A firm mattress best suited for stomach and back sleepers who prefer light contouring.

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Full Mattress Review

Both Casper and Amerisleep made a name for themselves by selling mattresses directly to consumers, with Amerisleep starting in 2010 and Casper in 2014. They were both early adopters of the mattress-in-a-box trend. While Casper started out as a New York-based company and is now owned by Carpenter Co., an international foam manufacturer, Amerisleep is still privately owned and operates out of Arizona.

When it comes to their signature mattresses, the Casper One is Casper’s flagship and the only all-foam model they offer, while the Amerisleep AS3 is the most popular pick in Amerisleep’s all-foam lineup. They share similar features and firmness levels, so choosing between the two can be tricky. That’s why we put them to the test in our mattress lab, compared company policies, and sifted through online reviews to give you the full picture.

Our Testing Team’s Take

Over the past decade, our testing team has evaluated nearly 2,000 mattresses in our Seattle Test Lab. Through this hands-on testing, we’ve developed a unique product research methodology that forms the backbone of our mattress rating system. 

Using cutting-edge technology, we pressure map each bed to identify where pressure points may form. We use similarly advanced tools to measure motion transfer across each mattress’ surface and heat retention.

We also have testing team members take mattresses home for weeks at a time, allowing them to mimic real-world use. Because our team members represent a variety of body weights and sleep position preferences, their perspectives can help you identify which might be the best mattress for you.

Our Verdict  

Like many all-foam beds, the Casper One and Amerisleep AS3 shine in pressure relief and motion isolation. Both beds “hug” the body and excel at absorbing movement, which can help couples who share a bed get better sleep. 

Logan Foley

Editorial Director

Side sleeper

140 pounds

Has too many dogs in the bed

“One of the things that stood out the most to me was how well the Casper One absorbed motion. I liked that I wasn’t bothered by movement on the other side of the bed. I also felt that the mattress had a good mix of pressure relief and pushback.”

The foam layers that add to pressure relief and motion isolation can also make moving around on the bed more difficult, which might bother people with less mobility and those who change sleeping positions often. These beds also both rate below average for edge support, so sitting or lying near the edges may feel less secure.

While the Casper One and Amerisleep AS3 have many similarities, there are differences, too. The Casper One costs a few hundred dollars less than the Amerisleep AS3, making it more attractive to shoppers on a budget. 

The Casper One also scores higher on temperature control, a feature that all-foam beds don’t always excel at. The Amerisleep is medium (5) in firmness, while the Casper One is medium firm (6). As a result, the Casper One can adequately support a wider variety of sleepers, while the Amerisleep isn’t ideal for sleepers over 230 pounds.

Colin Simpson

Product Research Manager

Side sleeper

190 pounds

Talks in sleep (like, a lot)

“As a side sleeper, the memory foam in the AS3 provides great pressure relief and motion isolation, so I barely notice when my partner moves. It’s not the most breathable mattress out there, and it’s not super bouncy, but the comfort and support are worth it to me.”

Construction and Materials

The Casper One and the Amerisleep AS3 are all-foam beds that share similar constructions. Both contain four layers consisting of a polyester blend cover, two polyfoam layers, and one memory foam layer. The foam in both beds is CertiPUR-US certified.

Casper One Breakdown 

The Casper One mattress is an all-foam model that rates medium firm, or 6 out of 10 on our firmness scale. This mattress measures 11 inches thick, which provides space for four layers, including the cover. Its cover consists of polyester, polyethylene, and Lycra, and the company says it’s intended to feel soft to the touch.

Beneath the cover, an open-cell polyfoam layer makes up the Casper One’s comfort system. This layer provides cushioning and lightly “hugs” sleepers. Its open-cell design means it contains small pockets of air that reduce heat build-up that often occurs in foam mattress layers. Beneath that layer is a memory foam layer. This layer also adds cushion and helps prevent sleepers from sinking down to the support core.

The Casper One’s support core is made of a high-density polyfoam. This layer adds stability to the mattress and provides firmness. All foam layers in the Casper One are CertiPUR-US certified, which means they are free from heavy metals, formaldehyde, and other potentially harmful chemicals. The cover has Oeko-Tex certification, which indicates that it has also been tested and found to be from potentially harmful substances.

Amerisleep AS3 Breakdown 

Like the Casper One, the Amerisleep AS3 is an all-foam mattress. It’s less firm than the Casper One, rating medium (5) on our scale. With a 12-inch profile, the AS3 measures an inch taller than the Casper One and contains four layers, including the cover, which is a blend made of polyester, cotton, and spandex. Amerisleep says the cover converts body heat into far infrared energy, which is intended to promote muscle recovery and cooling.

The uppermost foam layer in the AS3 is 3 inches thick and made of Bio-PurⓇ memory foam. This layer relieves pressure while conforming to the body, providing an even deeper “hug” than the Casper One. Beneath it sits a 2-inch zoned polyfoam layer made with what Amerisleep refers to as HIVEⓇ technology. This layer provides more cushion, and its zoned nature helps keep sleepers’ spines aligned.

Amerisleep calls its support core the Bio-CoreⓇ base, and it’s a 7-inch layer of high-density polyfoam. This layer adds to the mattress’ durability, stability, and firmness. Like the Casper One, all of the foam layers in the Amerisleep AS3 have earned CertiPUR-US certification. Amerisleep also notes that the AS3 is fiberglass-free.

Mattress Sizing and Weight 

Both the Casper One and Amerisleep AS3 are sold in twin, twin XL, full, queen, king, California king, and split king sizes. A split king mattress is actually two mattresses that fit together in the same bed frame to create a king size bed. Its split nature virtually eliminates motion transfer across the surface of the bed.

These mattresses have similar profile heights, with the Casper One measuring 11 inches and the Amerisleep AS3 measuring 12 inches. Standard fitted sheets should easily fit both models.

Performance Ratings 

The Casper One and Amerisleep AS3 both receive high performance ratings for their ability to relieve pressure. People who find the right firmness level in these beds likely won’t form pressure points. Side sleepers in particular may especially enjoy the conforming, pressure-relieving nature of these mattresses. Both beds also perform well in terms of motion isolation, which can help keep couples who share a bed from disturbing one another when they change sleeping positions during the night.

All-foam beds aren’t always great at keeping sleepers cool. In this area, the Casper One outshines the Amerisleep AS3. It receives slightly above-average ratings in temperature control, while the AS3 receives below-average ratings. Due to the “hug” of memory foam, moving around on these beds might feel difficult for some people. Because the Amerisleep AS3 is softer and more conforming than the Casper One, its foam may impede movement even more.

Because the Amerisleep AS3 is softer, it rated highly in terms of comfort and support with a small group of sleepers. Specifically, side sleepers weighing less than 230 pounds on this bed can usually find immense comfort and support, while back sleepers between 130 and 230 pounds can find adequate comfort and support. The Casper One received above-average ratings from side sleepers of all body weights, back sleepers weighing less than 230 pounds, and stomach sleepers weighing under 130 pounds.

Full Reviews: Other Casper and Amerisleep Models

Casper Dream Hybrid

Overall Rating:

6.7 /10

Price Range:

$1,195 – $2,390

Mattress Type:

Hybrid

Firmness Options:

Medium (5)

Casper Dream Max

Overall Rating:

6.9 /10

Price Range:

$2,495 – $4,990

Mattress Type:

Hybrid

Firmness Options:

Medium (5)

Casper Snow Hybrid

Overall Rating:

8.4 /10

Price Range:

$1,310 – $2,620

Mattress Type:

Hybrid

Firmness Options:

Medium (5)

Amerisleep AS1

Overall Rating:

7.2 /10

Price Range:

$949 – $1,698

Mattress Type:

Foam

Firmness Options:

Firm (7)

Amerisleep AS4

Overall Rating:

7.9 /10

Price Range:

$1,349 – $2,498

Mattress Type:

Foam

Firmness Options:

Medium Soft (4)

Amerisleep AS5

Overall Rating:

7.9 /10

Price Range:

$1,749 – $3,298

Mattress Type:

Foam

Firmness Options:

Soft (3)

Mattress Pricing and Policies

All-foam beds generally cost less than hybrid, latex, and airbed models, because synthetic foam costs less than steel, naturally derived latex, and the technology used in airbeds. As a result, both the Casper One and the Amerisleep AS3 cost less than many mattresses on the market.

The Casper One costs a few hundred dollars less than the Amerisleep AS3, likely for a few reasons. It has a thinner profile, which means it contains less material than the AS3. Amerisleep also offers a much longer warranty, and that likely results in higher prices. For other policies, like sleep trial and shipping, Casper and Amerisleep are nearly identical.

What Customers Are Saying

Both the Casper One and the Amerisleep AS3 have received thousands of mostly positive customer ratings and reviews online. The most common compliment for both beds is that they have improved reviewers’ sleep quality. People often praise the Casper One for having an ideal firmness level and praise the Amerisleep AS3 for its softness and contouring feel.

Some reviewers have complained that the Casper One is too firm and that the Amerisleep AS3 is too soft. Reviews like these are a good reminder to consider your body weight and sleep position preferences when choosing the ideal mattress firmness for your body.

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