INSIDE THE MATTRESS

Weight. Warmth. What happens inside?

See compression and heat pathways together, through four different mattress constructions.

THESSA Editorial3 min read

Heavy load. Heat pathways. Side by side.

Unloaded surface↕CompressionHeat flowRestricted airflowMoisture vapour

01 · Natural Comfort

THESSA

Wool + latex + pocket springs

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HEAVY LOAD

Deep cushioning. Local support.

Wool and latex cushion the weight. Individual springs compress beneath them.

HEAT & MOISTURE

Wool buffers moisture.

Wool absorbs and releases moisture vapour. Air can move through the spaces between springs.

02 · Construction type

Bonnell

Connected, open coils

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HEAVY LOAD

A connected response.

Wire links spread compression across neighbouring springs.

HEAT & MOISTURE

Vapour leaves with moving air.

Moisture vapour can pass through breathable upholstery and leave through the open coil cavity with air moving into the room. Cover and padding control its passage; steel springs do not absorb moisture.

03 · Construction type

All-foam

Soft memory-foam example

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HEAVY LOAD

A deeper cushion sink.

Soft memory foam compresses over a firmer, supportive core. Firmness and layer depth change the feel.

HEAT & MOISTURE

Airflow depends on the foam.

This low-airflow example limits ventilation. More breathable foams behave differently.

04 · Construction type

Simple pocket spring

Thin foam + individual coils

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HEAVY LOAD

Less comfort-layer travel.

Thin foam compresses above independent coils. The spring core still carries the load.

HEAT & MOISTURE

Air space below the foam.

The core has room for air. Cover and foam choices affect surface warmth.

Illustrative compression, not a measured scale. Heated weights show a thermal pathway, not a temperature test.

Heat and moisture follow different paths. Red arrows trace heat; dashed blue arrows trace moisture vapour. In Bonnell, vapour can pass through breathable upholstery and leave with air through the open coil cavity. Cover and padding control that passage. THESSA’s wool also absorbs and releases vapour, buffering moisture at the surface. An open spring core leaves space for air to move; the low-airflow foam example restricts that movement.

At a glance.

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Comfort, support, response and heat pathways in four constructions.
Compare	THESSA	Bonnell	All-foam	Simple pocket spring
Comfort	Latex + wool	Foam or fibre; varies	Soft memory foam here	Thinner foam or fibre
Support	Individual pocket springs	Wire-linked springs	Continuous foam core	Individual pocket springs
Response	Yielding latex · local coils	Springy · connected	Conforming foam	Local coils · less cushion
Heat & moisture	Wool buffers vapour · open core	Air space between coils	Air permeability varies	Air space between coils

How to read the illustrations

The THESSA illustration uses Natural Comfort. The other constructions are representative examples; individual products vary. Compression is illustrative, not a prediction of sink depth. Thin comfort layers do not by themselves mean inadequate support.

The heat panels trace a heated weight through the layers toward air spaces and the surroundings. Air moves between coils, not through steel. Wool absorbs and releases moisture vapour and also insulates. The soft memory-foam example has restricted airflow; other foams can be firmer and more breathable. These illustrations do not rank measured cooling performance.

Four builds. The details that matter.

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