Mattress Buying Guide: The Specs That Determine Whether You Sleep Well

A mattress is something you use for ten years. A good one supports your spine and improves sleep quality. A bad one can cause back pain, disturb your sleeping partner, and leave you waking up tired. But marketing terms like "ergonomic support" and "golden comfort" are meaningless. The structural specs are what help you make a real decision.

Two Layers: Support Core + Comfort Layer

The mattress experience is determined by two components: the spring (support core) determines overall firmness and shock absorption, while the comfort layer determines the immediate feel against your body.

Spring Types: Pocketed Coils vs. Bonnell (Open Coil)

Bonnell (Open Coil) Springs

Traditional spring design where all coils are connected by metal wire into a single unified network.

Characteristics:

Firm, even support with good bounce
Good breathability (air circulates between coils)
Simple construction; lower price
"One moves, all move": When you turn over or get up, vibrations travel through the entire spring network, easily disturbing a sleeping partner
Coils may deform and lose support over extended use

Best for: Single sleepers, limited budget, those who prefer a firm feel.

Pocketed Coil Springs

Each coil is individually encased in a non-woven fabric pocket. Coils are not connected to each other and compress independently.

Characteristics:

Zero motion transfer: Each coil moves independently; turning on one side doesn't transfer vibration to the other side — ideal for couples or partners with different sleep sensitivities
More precise body contouring (each contact point responds independently)
Silent (coils don't rub against each other)
Higher coil density = more precise support

Key spec: Coil count

Under 1,000 coils: Entry-level; coils are thicker and less conforming
1,000–2,000 coils: Mainstream quality range
Over 2,000 coils: High density; precise support; for those who prioritize sleep quality

There's also an upgraded version called micro-coils or mini pocketed coils, with smaller and thinner springs (~2cm diameter), reaching thousands per square meter for exceptional body contouring. Typically found in premium mattresses.

Comfort Layer Materials

Natural Latex

Source: Extracted and processed from rubber tree sap.

Characteristics:

Good elasticity with "responsive bounce" — compresses and springs back quickly
Naturally antibacterial and anti-mite (latex proteins naturally inhibit dust mites)
Good breathability; doesn't trap heat
Heavier than foam

Identifying genuine natural latex:

Authentic natural latex content is typically ≥90% (some products specify 95%+)
Look for rubber association certification (SGS or Oeko-Tex 100)
Synthetic latex (SBR) is cheaper with similar feel but worse durability — it crumbles over time
Natural latex has a faint natural rubber scent; synthetic latex has a more chemical odor

Memory Foam (Slow-Recovery Foam)

Characteristics:

Slowly conforms to body shape under pressure; excellent "cradling" sensation
Outstanding pressure relief at shoulder and hip contact points
Not for everyone: If you prefer a bouncy feel, memory foam can feel like you're "stuck in quicksand"
Temperature-sensitive: firms up in cold; softens in heat
Poor breathability; prone to heat retention (especially with high-density memory foam)

High-Density Foam

Density unit: D (kg/m³)

D < 25: Low density; compresses easily, poor durability
D 30–40: Mainstream quality; balanced support
D > 45: High density; strong support; compresses slowly under sustained weight

Higher foam density in the comfort layer means longer mattress lifespan and less "body impression" forming over time.

Firmness: The Core for Spinal Health

Mattresses aren't better softer or better firmer — the key is keeping your spine in its natural alignment.

Problem with too-soft mattresses: Lower back hangs unsupported, causing compensatory muscle tension over time Problem with too-firm mattresses: Shoulders and hips bear excessive pressure, affecting circulation

General guidelines:

Body weight ≤ 60kg: Soft to medium
Body weight 60–80kg: Medium
Body weight ≥ 80kg: Medium-firm
Primary sleep position: side sleeping → slightly softer to allow shoulder and hip to sink slightly, keeping spine straight
Primary sleep position: back sleeping → medium or slightly firm for adequate lower back support

Environmental Safety: What Certifications to Check

A mattress is pressed against your body for 8 hours a day. Formaldehyde and VOC off-gassing matter.

Recommended certifications:

Oeko-Tex Standard 100: Tests for harmful substances including formaldehyde, heavy metals, pesticide residues
CertiPUR-US: Safety certification for foam materials; US standard
Natural Latex SGS Certification: Confirms natural latex content percentage

One Measurement Before Buying

Mattress height + bed frame height determines knee bend angle when getting up. A common problem: overly thick mattresses make the sleeping surface too high — difficult for elderly users or shorter individuals to get up comfortably.

Recommended total height: 45–55cm from mattress base to floor (thighs roughly parallel to the floor when sitting on the edge; getting up requires minimal effort).

Parameter recommendations compiled from domestic and international independent mattress reviews and sleep science research literature.