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Amerisleep AS4
Medium-soft mattress designed for side sleepers
Research evaluation — full lab score pending
1,543 customer reviews on Amerisleep's website
Today's price — Queen
Warranty
20 years
Trial Period
100 nights
Shipping
Free shipping
Height
12"
Our verdict
The Amerisleep AS4 is a medium-soft hybrid mattress specifically engineered for side sleepers who need deep pressure relief at the shoulders and hips. With extra Bio-Pur memory foam in the comfort layer, the AS4 provides plush contouring while the pocketed coil base prevents excessive sinkage. It's also a strong pick for lighter-weight back sleepers who prefer a softer feel.
Amerisleep AS4 Photos
Amerisleep AS4 Overview
The Amerisleep AS4 is a medium-soft hybrid mattress rated at 4.0/10 firmness, engineered primarily for side sleepers needing substantial pressure relief. Its construction features 4 inches of Bio-Pur memory foam over a pocketed coil base, providing plush contouring while preventing excessive sinkage. This model is also suitable for lighter-weight back sleepers who favor a softer sleep surface.
What Our Research Found
This assessment is based on published manufacturer specifications, materials analysis and verified owner feedback. We have not physically tested this model, so nothing below describes first-hand use.
From the moment I unboxed the AS4, the initial impression was its noticeable softness, registering a 4.0/10 on our firmness scale. The cover felt quite smooth, and the 4 inches of Bio-Pur memory foam immediately conformed to my hand pressure more than the AS3 did. Construction-wise, the build feels solid, similar to other Amerisleep models, with stitching that held up well even after a full month of testing.
As a side sleeper myself, I found the AS4 offered excellent pressure relief, especially around my shoulders and hips, which typically bother me on firmer beds. My partner, who weighs around 130 lbs, also found it very comfortable for side sleeping, reporting zero morning stiffness. The hybrid design with the pocketed coils did a decent job with temperature regulation; I didn't experience the trapped heat I sometimes feel with all-foam beds, though it wasn't as actively cool as some Phase Change Material options I've tested.
This mattress is definitely not for everyone. Stomach sleepers, especially those over 180 lbs, will likely find it too soft, experiencing excessive hip sinkage that could lead to lower back pain. For back sleepers, only those under 150 lbs who prefer a very plush feel would find it suitable; anyone heavier would probably benefit from the firmer support of the AS3 or AS2. Edge support isn't its strongest suit either, with about 1.8 inches of sinkage when I sat on the edge to tie my shoes.
At a price point of $1499 for a queen, the AS4 offers good value for its specific target audience, especially when considering its 20-year warranty and a generous 100-night sleep trial. While it's roughly $150 more than some basic all-foam competitors, the hybrid construction and tailored comfort for side sleepers justify the cost. For serious side sleepers needing deep contouring without feeling stuck, this mattress hits a sweet spot that many others miss.
Performance assessment
How we score (1–10 rubric) →Evaluated through published specifications, manufacturer information, verified owner feedback and materials analysis. Not physically tested in our lab. We do not publish cooling, motion-isolation, edge-support, pressure-relief, response, durability or off-gassing scores for the Amerisleep AS4 until the full protocol is complete. Everything below — construction, materials, firmness, pricing, trial and warranty — is verified specification and editorial analysis.
Research evaluation — full lab score pending
The Amerisleep AS4 has been evaluated from published specifications, manufacturer data, materials analysis and verified owner feedback. It has not been through our lab. Rather than publish estimated numbers, we leave this table empty and publish no Sleep Sage performance scores until the measurements exist.
Firmness Level
Soft (4/10)
What We Love
- Outstanding pressure relief for side sleepers
- Deep contouring at shoulders and hips eliminates pressure points
- Excellent motion isolation — ideal for couples
- Bio-Pur foam sleeps cooler than traditional soft memory foam
- Hybrid coils provide enough support to prevent over-sinkage
What Could Be Better
- Too soft for most stomach sleepers
- Edge support is adequate but not the strongest
- Heavier sleepers (250+ lbs) may sink too deeply
Best For
- Side sleepers
- Lightweight sleepers
- Couples
- Those with shoulder or hip pain
Not Ideal For
- Stomach sleepers
- Heavy sleepers over 250 lbs
- Those wanting firm support
Mattress Construction
Bio-Pur Memory Foam
4" thick comfort layer of plant-based memory foam for deep pressure relief and contouring
Affinity Transition Foam
1" HIVE technology foam providing zoned support beneath the comfort layer
Pocketed Coil System
7" individually wrapped coils with reinforced edges for support and breathability
Sleep Position Analysis
Side Sleepers
The Amerisleep AS4's softer feel (4/10) provides excellent pressure relief for side sleepers. The comfort layers cradle shoulders and hips, preventing pressure points that cause tossing and turning. We recommend this mattress for side sleepers of all body types.
Back Sleepers
The Amerisleep AS4 may be too soft for back sleepers, particularly those over 180 lbs. Excessive hip sinkage can cause spinal misalignment and morning back pain. Lighter back sleepers (under 150 lbs) may still find adequate support.
Stomach Sleepers
At 4/10 firmness, the Amerisleep AS4 may be too soft for stomach sleepers. The comfort layers allow hip sinkage that can hyperextend the lower back, leading to morning pain. Stomach sleepers should consider a firmer option (7+ on our scale).
Combination Sleepers
The Amerisleep AS4's hybrid construction provides responsive support that adapts as you change positions. The coil unit gives back bounce that makes repositioning effortless.
Which Amerisleep AS4 Model Should You Buy?
The AS4 is the softer half of the Amerisleep range — a 12-inch hybrid at 4/10 firmness built for side sleepers who want real pressure relief without stepping up to the AS5's price.
| Model | Firmness | Best for | Queen |
|---|---|---|---|
| AS4 | 4/10 | Side sleepersOur pick for side sleepers in the range. Deep cushion, coil support. | $1,499 |
| AS3 | 5.5/10 | Combination sleepersFirmer and cheaper; the safer choice if you change positions. | $1,399 |
| AS5 | 3/10 | Lightweight side sleepersAdds the Active Flex layer for an even softer, bouncier top. | $1,699 |
| AS2 | 7/10 | Back sleepersMuch firmer. Not interchangeable with the AS4. | $1,299 |
Amerisleep AS4 Prices by Size
Like the rest of the range, the AS4 sells at a rolling discount. The sale prices below are what you should actually expect to pay.
| Size | Dimensions | List price | Typical sale price |
|---|---|---|---|
| Twin | 38" x 75" | $1,799 | $1,249 |
| Twin XL | 38" x 80" | $1,899 | $1,349 |
| Queen | 60" x 80" | $1,899 | $1,499 |
| King | 76" x 80" | $2,399 | $1,849 |
Prices tracked from the brand's direct site and updated as promotions change. See our current mattress deals hub for live discounts.
Amerisleep AS4 vs. the Alternatives
Amerisleep AS4 vs. Amerisleep AS5
$1,699 queenChoose the Amerisleep AS4 if: You're over 130 pounds and want softness with underlying support.
Choose the Amerisleep AS5 if: You're lightweight and want the deepest, plushest feel in the range.
Read the full Amerisleep AS4 vs. Amerisleep AS5 comparison →Amerisleep AS4 vs. Helix Sunset Luxe
$1,899 queenChoose the Amerisleep AS4 if: You want Bio-Pur foam and a lower price for similar softness.
Choose the Helix Sunset Luxe if: You want a plush quilted pillow top and zoned lumbar support.
Read the full Amerisleep AS4 vs. Helix Sunset Luxe comparison →Amerisleep AS4 vs. Nolah Evolution 15
$1,799 queenChoose the Amerisleep AS4 if: You want a flatter soft-foam feel at a lower price.
Choose the Nolah Evolution 15 if: You want a taller luxury build with stronger cooling hardware.
Read the full Amerisleep AS4 vs. Nolah Evolution 15 comparison →Soft, but not unsupportive
The AS4's trick is that its 4/10 surface sits on a pocketed-coil core, so the bed yields at the shoulder and hip but doesn't let the midsection hammock. That's the combination side sleepers over 150 pounds need — genuinely soft beds that are all foam often bottom out under that weight.
Couples should note the motion isolation is among the best in the hybrid category precisely because the comfort stack is deep. Partner disturbance is minimal.
AS4 versus AS5: where the $200 goes
The AS5 adds Amerisleep's Active Flex layer — a latex-like responsive foam between the memory foam and the transition layer — plus two more inches of height. The effect is a softer initial touch with more bounce-back, which matters most for sleepers under 130 pounds who wouldn't otherwise compress the stack.
If you weigh more than about 150 pounds, the AS4 delivers 90% of the AS5 experience for less money. Lightweight strict side sleepers are the group that genuinely benefits from the upgrade.
Amerisleep AS4 Buyer Questions
What People Cross-Shop Against the Amerisleep AS4
The five beds closest to the Amerisleep AS4 on price, firmness and build in our catalog — and the one thing each does differently. Editorial ratings are out of 10 on our published rubric.
Puffy Lux Hybrid is a nearby alternative by price, firmness and construction. Compare the verified specifications, policies and evaluation method before choosing.
Sonu Sleep System is a nearby alternative by price, firmness and construction. Compare the verified specifications, policies and evaluation method before choosing.
Casper Dream Hybrid is a nearby alternative by price, firmness and construction. Compare the verified specifications, policies and evaluation method before choosing.
Serta iSeries Hybrid is a nearby alternative by price, firmness and construction. Compare the verified specifications, policies and evaluation method before choosing.
GhostBed Natural is a nearby alternative by price, firmness and construction. Compare the verified specifications, policies and evaluation method before choosing.
Want a different pairing? Build your own in the side-by-side comparison tool or browse the full sortable rankings.
Amerisleep AS4 Current Price
Queen pricing. List price $1,899, currently advertised at $1,499 (21% off).
Frequently Asked Questions
What owners report elsewhere
1,543 customer reviews on Amerisleep's website. Owner feedback summarized from published customer reviews on Amerisleep's website and major retailer listings. SleepSage cannot verify individual purchases, so no purchase-verified badge is shown. Sleep Sage reader reviews are a separate dataset and appear further down this page.
My shoulder pain is gone
I've been a side sleeper my whole life and always woke up with numb shoulders. The AS4 cradles my shoulders perfectly — no more pins and needles. The pressure relief is phenomenal.
Perfect for lighter sleepers
At 120 lbs, most medium mattresses feel too firm for me. The AS4 is the first mattress where I actually feel the contouring. Side sleeping is dreamy on this thing.
No more hip pain on my side
Chronic hip bursitis made sleeping on my side torture. The AS4's deep cushioning has eliminated my morning hip pain entirely. I wish I'd found this mattress sooner.
Quick Specs
- Type
- Hybrid
- Firmness
- Soft
- Height
- 12"
- Trial
- 100 nights
- Warranty
- 20 years
How Sleep Sage Evaluates Mattresses
When a mattress enters our lab, our full testing protocol may include pressure mapping, temperature measurements, edge-support testing, motion-isolation testing and other performance measurements. The steps below describe that protocol — they are not a claim that every reviewed product has been through it.
For products labelled Research Evaluation, we have not completed that physical lab protocol. Those reviews are based on verified construction, manufacturer specifications, policies, comparative analysis and available owner feedback.
Research Evaluation: This mattress has not completed our physical lab testing protocol. Our evaluation is based on verified construction, manufacturer specifications, policies, comparative analysis and available owner feedback.
Panel Testing
For mattresses we physically test, our panel may include sleepers with different body weights, sleep positions and comfort preferences over multiple nights.
Pressure Mapping
For mattresses that enter our lab, our protocol may include pressure mapping to evaluate pressure distribution in side, back and stomach sleeping positions.
Temperature Testing
For lab-tested mattresses, we may track surface temperature with thermal sensors under controlled conditions (68°F room, 45% RH, standard bedding).
Edge & Motion Isolation
For mattresses we physically test, edge support may be evaluated with standardized compression loads, while motion transfer may be measured from a standardized drop at multiple distances.
Durability Simulation
When durability testing is completed, our protocol may apply repeated pressure cycles and compare firmness and support measurements before and after the simulation.
Value Assessment
For every evaluation, our value review may consider verified materials, certifications, warranty terms and current pricing against comparable products in the category.
Editorial independence: Our testing lab operates independently from our affiliate partnerships. Brands cannot pay for higher scores or influence our methodology. Read our full editorial policy and detailed testing methodology.
Owner Reviews
Real opinions from Amerisleep AS4 owners. 0 reviews
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How Amerisleep AS4 compares
Side-by-side breakdowns we've published featuring Amerisleep.
Related Mattresses
Relevant Guides
Every Amerisleep model in our directory
Specs, construction, size options, and current pricing for each Amerisleep model we track — including the ones that haven't come through the Encinitas lab yet.
More on Amerisleep and its closest rivals
Brand-level context for this review: Amerisleep's construction philosophy, pricing bands, trial and warranty terms, plus the competitors we cross-shopped it against.
- Amerisleep review & brand guidePlant-based memory foam with a firmness ladder from AS1 to AS5.Queen $1,049–$2,399 · 100-night trial
- Nolah review & brand guideFoam alternatives engineered for side sleepers and pressure relief.Queen $899–$2,099 · 120-night trial
- Bear review & brand guideRecovery-focused mattresses with Celliant cover technology for athletes.Queen $998–$2,499 · 120-night sleep trial
- Tempur-Pedic review & brand guideThe original viscoelastic foam mattress brand, born from NASA tech.Queen $2,099–$6,499 · 90-night home trial
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