Amerisleep AS4 Review 2026: Best for Side Sleepers and Pressure Relief

What was the Amerisleep AS4?

The AS4 sat at firmness 4/10, one step softer than the bestselling AS3 (5/10 medium) and one step firmer than the AS5 (3/10 soft). Its construction was three layers:

• 3-inch Bio-Pur comfort layer: one inch thicker than the AS3's standard comfort layer, giving deeper shoulder and hip contour for side sleepers.
• 2-inch HIVE transition layer: hexagonal cutouts that are softer under the shoulders and hips, firmer under the lumbar. The same zoned logic runs through the entire Amerisleep lineup.
• 7-inch Bio-Core support base: high-density foam backing the 20-year warranty.

The 12-inch total height, 100-night trial, and 20-year warranty were identical to the rest of the lineup. The AS4 was all-foam only; there was never an AS4 Hybrid variant.

Why Amerisleep discontinued the AS4

Amerisleep updated the AS3 in late 2025 to cover a wider medium-to-medium-soft firmness band. With the revised AS3 absorbing the medium-soft position, the AS4 became redundant. Amerisleep reduced the lineup to AS1, AS2, AS3, AS5, plus the Organica and hybrid variants, and retired the AS4 for new orders. Existing AS4 owners retain their full warranty.

The AS4 URL (amerisleep.com/as4.html) now redirects to the AS3 product page. That redirect is the clearest signal of the brand's intended replacement.

Choosing a replacement: AS3, AS5, or something else?

Mattress	Type	Firmness	Trial	Warranty	Queen price
Amerisleep AS3	All-foam (Bio-Pur)	Medium 5/10	100 nights	20 years	From $1,049
Amerisleep AS5	All-foam (Bio-Pur)	Soft 3/10	100 nights	20 years	From $1,449
Amerisleep AS3 Hybrid	Hybrid (foam + coils)	Medium 5/10	100 nights	20 years	From $1,449
Saatva Classic	Innerspring hybrid	Plush Soft / Lux Firm / Firm	365 nights	Lifetime	~$1,395
Helix Midnight	Hybrid	Medium 6/10	100 nights	10 years	~$1,374

The decision tree is straightforward. If you wanted the AS4 for side sleeping pressure relief at a medium-soft feel, the updated AS3 covers that range; Amerisleep explicitly widened the AS3's comfort band for this reason. If your shoulders or hips need more give than a medium provides, the AS5 (soft 3/10) is the better fit. If you wanted the AS4 because you share the bed with a back sleeper who needs firmer support, the AS3 Hybrid pairs foam pressure relief with coil responsiveness and stronger edge support.

What the AS4 experience carries over to the current lineup

Every Amerisleep model shares the same platform features that made the AS4 worth considering:

• Bio-Pur foam: partially plant-based, open-cell structure for breathability, faster response than dense petroleum memory foam. CertiPUR-US certified.
• HIVE 5-zone support: hexagonal cutout pattern creating five distinct firmness zones. Shoulders and hips get softer support; the lumbar zone stays firmer to maintain spinal alignment.
• 100-night trial: full refund if you return, with removal assistance. Long enough to know whether the firmness matches your sleep position and body weight.
• 20-year warranty: split structure where years 1-10 cover repair or replacement at no cost for manufacturing defects or sagging over 1.5 inches. Years 11-20 cover replacement at 50% of the original purchase price.

AS3 vs legacy AS4: side-by-side specs

Mattress	Type	Firmness	Trial	Warranty	Queen price
Amerisleep AS3 (2026)	All-foam Bio-Pur	Medium 5/10	100 nights	20 years	From $1,049
Legacy Amerisleep AS4	All-foam Bio-Pur	Medium-Soft 4/10	100 nights	20 years	Discontinued

The one spec that matters here is firmness: 5/10 vs 4/10. That is not a dramatic difference, and Amerisleep's own redirect confirms they consider the current AS3 to be the functional equivalent. Sleepers on the boundary between medium and medium-soft who are undecided should use the 100-night trial to test the AS3 first; the trial removes the financial risk of the firmness call.

Side sleeper guide: which firmness level is right?

The AS4 existed specifically because dedicated side sleepers need more pressure relief than the standard medium AS3 provided. Here is the practical breakdown by body weight:

• Under 130 lb, strict side sleeper: the AS5 (soft 3/10) is usually the better fit. Lighter frames do not compress the comfort layers enough to reach the support core on a medium, which can leave the spine unsupported.
• 130 to 200 lb, side or side-back combination: the updated AS3 (medium 5/10) covers this range well. The widened firmness band Amerisleep built into the 2025 update addresses the medium-soft position the AS4 held.
• Over 200 lb, side sleeper: the AS3 Hybrid adds 7-inch pocketed coils under the Bio-Pur comfort system. Coils handle heavier loads with less permanent compression over time, which matters for durability on a 20-year warranty product.

Frequently asked questions

Is the Amerisleep AS4 still available?

No. The AS4 was discontinued in late 2025. The product URL now redirects to the AS3, which Amerisleep updated to cover the medium-to-medium-soft firmness range the AS4 occupied.

What is the closest current Amerisleep model to the AS4?

The AS3 for most sleepers. If you specifically need a softer-than-medium feel, the AS5 (3/10 soft) is the next option. The AS3 sits at 5/10 medium; the AS4 was 4/10 medium-soft. The gap is one step on a 10-point scale.

Does my AS4 warranty still apply?

Yes. Existing AS4 owners retain their 20-year warranty. Amerisleep's warranty terms do not change when a model is discontinued. Contact Amerisleep support directly for warranty claims on a delivered unit.

Is the AS3 firmer than the AS4?

Slightly. The AS4 was rated 4/10 medium-soft; the current AS3 is 5/10 medium. Sleepers who found the AS3 too firm before the AS4 was discontinued may find the updated AS3 bridges that gap. If not, the 100-night trial allows a full refund before committing.

Who should choose the AS5 instead of the AS3?

Lightweight side sleepers under 130-150 lb who sleep exclusively on their side and feel that a medium mattress does not give enough at the shoulder and hip. The AS5 (3/10 soft) provides the deepest contouring in the Amerisleep all-foam range.