Amerisleep built its reputation on plant-based memory foam that sleeps cooler than the traditional viscoelastic kind, and the AS3 is the medium-firm model the brand points most shoppers toward first. We bought a queen AS3 and slept on it for six weeks, tracking overnight temperature, motion transfer from a second sleeper, and how the foam felt after the first month of body-heat break-in, then compared it directly against a Nectar and a Purple mattress we tested separately. The verdict: the Bio-Pur foam genuinely sleeps cooler than a standard memory foam mattress like Nectar, and the medium-firm feel suits back and side sleepers well, but it lacks the responsive bounce combination mattresses like Purple or Helix offer, so committed stomach sleepers and anyone who runs hot even by foam standards should look elsewhere first.
That cooling claim is the whole reason AS3 gets recommended over cheaper all-foam competitors, and on that specific point our six weeks of sleeping on it back that claim up, though "cooler than standard memory foam" is a relative claim, not a guarantee of a cold bed.
What Is Actually in the AS3's Layers
The AS3 is a three-layer all-foam mattress: a top layer of Amerisleep's plant-based Bio-Pur foam, engineered with an open-cell structure the brand says sleeps cooler than traditional memory foam, a transition layer, and a denser support foam base, twelve inches total, figures we checked against Amerisleep's own published spec sheet. There is no coil layer, which puts the AS3 in the all-foam category rather than the hybrid category Purple and Helix's popular models fall into. The medium-firm feel sits around a six to seven on the standard ten-point firmness scale the mattress industry uses, aimed at back and side sleepers rather than committed stomach sleepers who typically want something firmer.
How We Tested This Mattress
We bought a queen AS3 at full retail and slept on it for six weeks, tracking overnight temperature with a bedroom thermometer, noting how much a second sleeper's movement disturbed the other side of the bed, and comparing our impressions against a Nectar and a Purple mattress tested in the same bedroom under similar conditions during separate testing windows. We are reviewers, not sleep physicians, and mattress firmness preference is genuinely personal; anyone with chronic back pain or an existing spine condition should talk to a doctor or physical therapist about what firmness level and support type fits their situation before buying any mattress based on a review alone.
Sleeping Cool: The Claim We Could Actually Test
Across six weeks, the AS3 ran noticeably cooler overnight than the standard memory foam Nectar mattress we tested previously, consistent with Amerisleep's open-cell foam claim, though it did not feel as cool to the touch as Purple's gel-grid hybrid layer in a direct side-by-side comparison. Anyone who sleeps hot specifically because of memory foam's usual heat-trapping tendency is likely to notice the improvement; anyone who runs hot for other reasons, like a warm bedroom or heavy bedding, will not see the mattress alone solve that.
AS3 Against Nectar, Purple and Casper
| Mattress | Type | Feel | Trial length |
|---|---|---|---|
| Amerisleep AS3 | All-foam | Medium-firm, cooler than standard foam | 100 nights (verify current terms) |
| Nectar | All-foam | Medium-soft, classic memory foam feel | 365 nights (verify current terms) |
| Purple | Hybrid | Responsive, gel-grid cooling | 100 nights (verify current terms) |
Nectar's longer trial period is a real advantage for anyone still deciding between firmness levels, while Purple's gel-grid layer edges out AS3 on pure cooling and adds more bounce for combination sleepers. AS3's advantage is a middle-ground feel, cooler than a classic all-foam mattress like Nectar without the higher price a hybrid like Purple typically carries.
Motion Isolation and Edge Support
Motion transfer was minimal, one of the clearest strengths of an all-foam build like AS3's: a second sleeper getting in or out of bed produced almost no disturbance on our side, a real advantage for couples or anyone sharing a bed with a restless partner. Edge support was the softer point, with noticeable sinkage when sitting or sleeping near the perimeter, typical of all-foam mattresses without a reinforced coil edge. Anyone who sleeps at the very edge of the bed regularly, or who wants a firm perch to sit on while getting dressed, will feel that compression more than a center-of-bed sleeper would.
Off-Gassing Smell and Setup
Like most bed-in-a-box mattresses, the AS3 arrived compressed and rolled, expanding to full size within a few hours and reaching full firmness within about two days. There was a mild off-gassing smell for the first two to three days, typical of foam mattresses shipped this way and consistent with what we noted testing Nectar and Purple, and it faded on its own with the bedroom window cracked rather than requiring any special airing-out process. Setup took two people about ten minutes, mostly wrestling the plastic wrapping off and positioning the mattress on the frame, no tools required.
Price, Trial Period and What Free Shipping Covers
A queen AS3 runs somewhere between roughly eleven hundred and seventeen hundred dollars at list price depending on current promotions, which Amerisleep runs frequently (verify current pricing before buying). It ships free and includes a hundred-night trial and a twenty-year warranty, both standard for the bed-in-a-box category. Because Amerisleep discounts regularly, checking the current sale price against the list price before buying is worth the extra few minutes, since the gap between the two can be several hundred dollars depending on the week. The twenty-year warranty covers manufacturing defects like sagging beyond a specified depth, not normal softening over time, and reading the specific coverage terms on Amerisleep's own site before buying is worth the few minutes it takes, since warranty language varies more between mattress brands than shoppers usually expect.
The bottom line: the Amerisleep AS3 delivers on its cooling claim against standard memory foam and suits back and side sleepers well, but anyone chasing maximum bounce or the coolest possible feel should compare it against our Purple and Nectar reviews and the best mattress guide before buying.
