Sweetnight CoolNest vs Amerisleep AS3: Which Foam Mattress Wins?

Two all-foam mattresses aimed at hot sleepers, each with its own cooling story and its own trial terms. The Sweetnight CoolNest builds its pitch around a layered cooling system and a five-zone support core, while the Amerisleep AS3 pairs a plant-based memory foam with a heat-drawing cover and a much longer warranty. Both are sold direct, both ship free, and both let you try the mattress at home before committing. Skip the Amerisleep AS3 if you want a profile taller than 12 inches; consider the Sweetnight CoolNest’s 14- or 16-inch options instead. The differences show up in feel, height options, cooling claims and how long the maker stands behind the product. This comparison lays out what each brand states about its own mattress so you can match one to your sleep position, your temperature habits and your budget horizon.

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Which mattress should you choose between the CoolNest and the AS3?

The Amerisleep AS3 is the stronger pick for sleepers who want a medium feel that works across all positions, a 12-inch profile, a 100-night trial and a 20-year warranty, all backed by a fiberglass-free, plant-based foam construction. The Sweetnight CoolNest suits shoppers who want a choice of three thicknesses, a five-zone support core and a cooling system the brand rates as up to 8 degrees cooler, with a 100-night trial and a 10-year warranty. Both mattresses are all-foam, both ship free, and both are CertiPUR-US certified or, in the AS3’s case, described as non-toxic and fiberglass-free. The verdict below breaks down each decision axis.

How do the two mattresses feel and support you?

The AS3 is described by Amerisleep as a medium feel built for all sleeping styles, with balanced comfort and support and targeted support from its HIVE technology. That positioning makes it a straightforward choice for combination sleepers and couples who cannot agree on firmness. The CoolNest takes a different route: Sweetnight describes an all-foam feel with body-cradling support and pressure relief, aimed at side sleepers who need pressure-point contouring, and a five-zone ergonomic support design with nine comfort bars that maps support across the body. If you sleep primarily on your side and want contouring at the hips and shoulders, the CoolNest’s zoning and its stated side-sleeper focus speak directly to that need. If you rotate between positions or share the bed with a partner who sleeps differently, the AS3’s medium, all-positions positioning is the more flexible of the two.

What is each mattress made of?

Both mattresses are all-foam constructions, and both brands describe cooling features inside the foam itself rather than only in the cover. The comparison table below lines up what each brand states about its own product.

The Amerisleep AS3 queen price of $1,149 against a list price of $1,749 comes from the brand’s own product data, and prices change with promotions. The CoolNest price is not published here, so this comparison draws no value conclusion from price between the two. What can be said without a figure: the AS3 carries a warranty twice as long as the CoolNest’s, and both brands offer the same 100-night trial length.

Which one sleeps cooler?

Both brands put a number on their cooling claim, and the two numbers describe different things. Sweetnight says the CoolNest system feels up to 8 degrees cooler, achieved through a CoolNest cover working with PCMflux high-resilience foam, a gel-infused memory foam layer and a 3D airflow structure design. Amerisleep says its Refresh cover draws heat from the skin and that the sleeping surface stays on average 7 degrees cooler over an eight-hour night, while its plant-based Bio-Pur foam uses an open-cell design to let more air circulate than traditional foam. The CoolNest also offers three thicknesses, and the brand labels the 12-inch option as essential cooling, the 14-inch as enhanced cooling and the 16-inch as ultimate cooling and support, so you can pick a cooling tier rather than a single configuration. If your main problem is sleeping hot, both mattresses address it directly; the CoolNest gives you thickness choices, while the AS3 gives you a cover-and-foam combination with a published average temperature figure.

Who should buy the Sweetnight CoolNest?

The CoolNest is the better fit for side sleepers who want pressure-point contouring and a body-cradling all-foam feel, and for shoppers who want to choose their mattress height rather than accept a single profile. Its five-zone support design with nine comfort bars is built to vary support across the body, which suits sleepers who feel pressure at the hips and shoulders on a flat-support mattress. The three thickness options, 12, 14 and 16 inches, let you match the mattress to your frame and your preferred depth of cushioning, and the brand’s own labeling ties each thickness to a cooling tier. Certifications matter to some buyers: the CoolNest’s foam is CertiPUR-US certified and its fabric passes the OEKO-TEX STANDARD 100. The 100-night trial and 10-year warranty round out the package. Choose the CoolNest if you sleep on your side, want a zoned foam core, and like the idea of picking your thickness.

Who should buy the Amerisleep AS3?

The AS3 is the better fit for sleepers who change positions during the night, for couples who need one mattress to work for two different sleep styles, and for anyone who weighs warranty length heavily in a purchase. Amerisleep describes the AS3 as a medium feel that balances comfort and support for all sleeping styles, with HIVE technology providing targeted support and a plant-based Bio-Pur foam that the brand says snaps back to its shape in seconds rather than leaving you sunk in. The 12-inch profile is a single, defined height, which simplifies the choice if you do not want to compare thicknesses. The fiberglass-free, non-toxic construction and the made-in-the-USA note appeal to buyers who check materials closely. The 100-night trial matches the CoolNest, and the 20-year warranty runs twice as long. Choose the AS3 if you are a combination sleeper, share the bed, and want the longer warranty.

What do trial, warranty and shipping look like?

The two brands match on trial length and differ on warranty. Both the CoolNest and the AS3 carry a 100-night trial, so you get the same window to decide at home. The CoolNest is covered by a 10-year warranty with free U.S. shipping. The AS3 is covered by a 20-year warranty with free shipping and easy, free returns. Neither brand’s terms are longer or shorter on the trial itself, so the decision here comes down to how much the warranty duration matters to you: the AS3’s coverage runs twice as long as the CoolNest’s. If you want to read the full detail of each program, the brand pages linked in the table above carry the complete terms.

Is the Saatva Classic a good alternative to either foam mattress?

If you have ruled out all-foam construction, or if you want a longer trial and a longer warranty than either of these two offers, the Saatva Classic is the alternative worth considering. It is an innerspring mattress with a dual-coil design, a three-inch Euro pillow top, and 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. It comes in two heights, 11.5 and 14.5 inches, and includes Lumbar Zone technology for spinal alignment. Saatva pairs the mattress with a 365-night home trial, free white-glove delivery that includes in-room setup and removal of your old mattress, and a lifetime warranty. The brand also notes CertiPUR-US certified foams, GREENGUARD Gold certification and an endorsement from the American Chiropractic Association. For shoppers who liked the AS3’s medium feel but wanted a coil base, or who wanted the CoolNest’s height options with a much longer trial, the Classic covers both angles.

Verdict: the Amerisleep AS3 wins this face-to-face for most sleepers. It matches the CoolNest on trial length, exceeds it on warranty at 20 years versus 10, offers a medium feel that works for every sleep position, and publishes a clear queen price of $1,149. The Sweetnight CoolNest remains the right call for dedicated side sleepers who want a five-zone support core and the choice of 12, 14 or 16 inches of thickness, and who value the CertiPUR-US and OEKO-TEX certifications on the foam and cover. Shoppers who want coils, a 365-night trial or a lifetime warranty should look at the Saatva Classic instead. Read the full Amerisleep AS3 review or the Sweetnight CoolNest review for the complete picture on each mattress.

Frequently asked questions

Do both mattresses come in the same sizes?

The CoolNest is offered in Twin, Full, Queen and King, with three thickness options across those sizes. The AS3 is offered in a range of sizes including Queen at 60 by 80 inches, and the all-foam version comes in a single 12-inch profile. Check each brand’s size guide before ordering if you need Twin XL, Cal King or a split configuration.

Is the AS3 Hybrid part of this comparison?

No. This comparison covers the all-foam AS3 only. Amerisleep sells the AS3 Hybrid as a separate model that combines foam and coils, and it is a different product with its own construction. If you want coils inside an AS3, that is a separate purchase decision from the all-foam version discussed here.

Which mattress is better for couples?

The AS3 is positioned by Amerisleep as a medium feel that suits all sleeping styles, which makes it the more flexible choice when two people share a bed with different sleep positions. The CoolNest is described as an all-foam feel aimed at side sleepers who need pressure-point contouring, so it fits a couple best when both partners sleep on their sides or want a body-cradling feel.

Do either of these mattresses come with a pillow or base bundle?

Sweetnight offers the CoolNest Ergonomic Cooling Pillow and the CoolNest Cooling Sheet Set as add-ons alongside the mattress, and runs bundle and save promotions on its site. Amerisleep offers the AS3 alongside its own selection of bases and frames. Bundles and promotions change, so check the current offer at checkout.

What if I want a longer trial than 100 nights?

Neither the CoolNest nor the AS3 offers more than 100 nights. If a longer home trial is a priority, the Saatva Classic comes with a 365-night home trial, free white-glove delivery and setup, removal of your old mattress, and a lifetime warranty. See the Saatva Classic review for the full details.

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