Amerisleep AS3 vs Casper Original: Which One Should You Buy?

The Amerisleep AS3 and the Casper Original are two all-foam mattresses that aim at the same middle ground: a medium feel that works for most sleep positions. Look elsewhere if you want a very soft or very firm feel; the Saatva Classic offers selectable comfort levels. The AS3 pairs plant-based Bio-Pur memory foam with HIVE targeted support and a Refresh cooling cover, and it is offered in both an all-foam and a hybrid version. The Casper Original stacks breathable Casper Signature Foam over zoned memory foam with three ergonomic zones. Amerisleep states the AS3 is fiberglass-free; Casper states its foams are CertiPUR-US certified. This face-to-face breaks down where each one pulls ahead.

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Which mattress should you choose between the Amerisleep AS3 and the Casper Original?

Choose the Amerisleep AS3 if cooling is your main complaint and you want a mattress engineered around it. Choose the Casper Original if you want a straightforward medium-foam feel with zoned support and a clear published price list. Both are all-foam designs with a medium feel, and both come with a 100-night trial. The differences sit in the cooling story, the height, and how much construction detail each brand puts in front of you.

How do the Amerisleep AS3 and Casper Original compare on paper?

Here is the side-by-side view. Every figure below comes from the official Amerisleep and Casper product pages.

How do the two mattresses feel and support you at night?

Both mattresses are sold as medium-feel beds, which is the most forgiving category for couples who do not agree on firmness. The AS3 describes its comfort as balanced for all sleeping styles, with HIVE technology delivering targeted support and airflow. The Casper Original uses Zoned Support with three ergonomic zones intended to support spinal alignment, layered under a top of breathable polyurethane foam and a second layer of zoned memory foam that conforms to absorb pressure.

The practical difference is height and layering. The AS3 stands at a 12-inch profile, one inch taller than the Casper’s 11 inches. Amerisleep also gives you a choice of build: the AS3 comes as an all-foam mattress or as the AS3 h Hybrid with foam and coils, so sleepers who want coil support under foam comfort have that path. Casper’s Original is an all-foam design with a durable polyurethane base.

For stomach sleepers, back sleepers and side sleepers alike, a medium feel with zoned support is a reasonable starting point. Neither brand publishes a firmness number on these pages, so if you have a strong preference for a very firm or very soft bed, you will want to use each brand’s trial period to confirm the feel suits you.

Which mattress sleeps cooler?

The Amerisleep AS3 makes cooling the centerpiece of its pitch. The Refresh cover is built from a fiber with high energy transfer that draws heat from the skin, and Amerisleep states the sleeping surface stays on average 7 degrees cooler over an eight-hour night. The plant-based Bio-Pur foam uses an open-cell design so more air circulates than in traditional foam, which Amerisleep links to less sweating and less tossing and turning. HIVE technology is credited with maximizing airflow alongside targeted support.

The Casper Original addresses heat with one clear claim: Casper Signature Foam increases airflow. Beyond that, the product page does not quantify a temperature difference. If a stated cooling figure matters to your decision, the AS3 is the one that publishes one.

What are the materials in each mattress?

The AS3 is built around Bio-Pur, a plant-based memory foam that Amerisleep describes as more breathable and responsive than traditional memory foam, snapping back to shape in seconds so you do not sink uncomfortably. The mattress is fiberglass-free, non-toxic, and made in the USA. The cover carries the Refresh Cooling Technology treatment, and the support layer uses HIVE technology.

The Casper Original lists three layers: a top layer of breathable polyurethane foam, a second layer of zoned memory foam, and a durable polyurethane base. All polyurethane foams are CertiPUR-US certified, meaning they are made without ozone-depleting chemicals and regulated phthalates, and tested for low VOC emissions under 0.5 parts per million.

Amerisleep states the AS3 is fiberglass-free. Casper’s page cites CertiPUR-US foam certification and does not address fiberglass, so this comparison makes no fiberglass claim for the Casper Original.

What do trial, warranty and shipping look like?

The AS3 comes with a 100-night sleep trial, free no-contact shipping, easy and free returns, and a 20-year warranty. The trial windows are close in length, so the clearer differentiator is the warranty: Amerisleep states 20 years in writing.

Which mattress is the better value without looking at price?

Value without a price tag comes down to what is included. The AS3 bundles a stated 20-year warranty, free shipping and free returns, a fiberglass-free build, a cooling cover, and a choice of all-foam or hybrid construction under one model name. The Casper Original bundles CertiPUR-US certified foams, zoned support, a published size chart with weights for every size, and a large public review base averaging 4.39 out of 5 from 17,942 reviews.

Casper also publishes a sleep specialist phone line for buyers who want to talk to someone before ordering. Amerisleep leans on its Newsweek Readers’ Choice Best Mattress 2026 recognition and an endorsement from the American Chiropractic Association. Which of those signals matters more is a personal call.

Who should buy the Amerisleep AS3, and who should buy the Casper Original?

Buy the Amerisleep AS3 if you sleep hot and want a mattress that names its cooling technology, quantifies a temperature difference, and offers a hybrid version if you later decide you want coils. It is also the pick if a long written warranty matters to you, since Amerisleep states 20 years, and if you want a 12-inch profile rather than 11. The AS3 suits combination sleepers who want one medium feel that works across positions, and it suits shoppers who value a fiberglass-free designation stated plainly on the product page.

Buy the Casper Original if you want a well-known all-foam mattress with three-zone spinal support, CertiPUR-US certified foams, and a size chart that lists exact dimensions and weights for all six sizes. It suits shoppers who prefer a slightly lower 11-inch profile, buyers who want to call a sleep specialist before ordering, and anyone who reads public reviews as part of the decision, since the Casper page carries a 4.39 out of 5 average across 17,942 reviews. It also suits people who like a brand that keeps its construction simple: three layers, one build, no variants to decode.

Neither mattress is the wrong choice for a hot sleeper or a combination sleeper. The AS3 simply says more about cooling, and the Casper says more about its foam certifications and its review record.

Is there an alternative if you want coils instead of foam?

Yes. The Saatva Classic is an innerspring mattress with a dual-coil design of triple-tempered recycled carbon steel coils, over 1,000 of them in full size and up, under a 3-inch Euro pillow top. It comes in three comfort levels: Plush Soft at 3 out of 10, Luxury Firm at 5 to 7 out of 10, and Firm at 8 out of 10, so you pick a firmness instead of accepting one. It carries a 365-night home trial, free white-glove delivery with in-room setup and old mattress removal, and a lifetime warranty. If the idea of an all-foam bed in either the AS3 or the Casper does not appeal, that is the direction to look.

World Sleep Almanac score: 7.9/10

The World Sleep Almanac editorial score is built from five criteria, each rated on the facts each brand publishes: price transparency at equal size, trial and return terms, warranty length, materials and construction detail, and public review evidence. The AS3 scores highest on cooling detail and warranty length; the Casper scores highest on published review volume and certification clarity. The overall figure reflects both products as a pair, not a lab test.

• Cooling and materials detail: 8/10 for the AS3’s stated temperature figure and fiberglass-free build, 7/10 for Casper’s airflow claim and CertiPUR-US foams.
• Trial and returns: 7/10 for the AS3’s 100-night free-return trial, 7/10 for Casper’s 100-day trial.
• Public reviews: 8/10 for Casper’s 4.39 out of 5 average across 17,942 reviews; Amerisleep cites 15,000 plus reviews averaging 4.7 stars.

Frequently asked questions

Is the Amerisleep AS3 fiberglass-free?

Yes. Amerisleep states on its AS3 product page that the mattress is fiberglass-free, eco-friendly and non-toxic. That claim is made by Amerisleep for the AS3 specifically.

Does the Casper Original come in a hybrid version?

No hybrid version of the Casper Original appears on its product page. The listed construction is all-foam: breathable polyurethane foam on top, zoned memory foam in the middle, and a polyurethane base. The AS3, by contrast, is offered as an all-foam model or as the AS3 h Hybrid with foam and coils.

How tall is each mattress?

The Amerisleep AS3 has a 12-inch profile height. The Casper Original is 11 inches tall across all six listed sizes, from Twin through California King.

Which mattress has a longer trial period?

The two trials are close in length. Amerisleep offers a 100-night sleep trial with easy and free returns. Casper describes a 100-day trial period during which the mattress is returnable. The AS3 pairs its trial with a stated 20-year warranty, which the Casper product page does not match with a published warranty term.

Can I choose a firmness level with either mattress?

Neither the AS3 nor the Casper Original offers multiple firmness options on their product pages. Both are sold in a single medium feel. If choosing between soft, medium and firm matters to you, the Saatva Classic offers Plush Soft, Luxury Firm and Firm as separate comfort levels.

Reviewed by the World Sleep Almanac editorial team. Updated 2026.