Choose your mattress: soft foam or memory foam

When we want to change bedding , it is often difficult to make a choice between the different proposals of comfort available to us. Which composition to choose for your mattress or mattress topper ? A High Resilience or Viscoelastic foam? What does that mean ?

From a technical point of view, foams are characterized by 3 criteria determining their comfort and their "physical appearance".

• Density : It indicates the weight of a block of foam per m3 (example: 35kg/m3 this indicates that a block of foam of 1m3 weighs 35kg). As an indication, our Osmoz mattress consists of a 6cm thick memory foam surface with a density of 50kg/m3. In the lower part, the 16cm thick high resilience foam has a density of 35kg/m3. This information is important in terms of durability and not in terms of comfort; a low density implies a less durable mattress but will not change its comfort. We speak of low density below 30kg/m3.

• KPA : Comfort is expressed by an index expressed in KPA (Kilopascal), this index consists of measuring the pressure exerted on the foam of your mattress . If you find it difficult to push your hand into your mattress , for example, it means that it will tend to be firm. The higher the KPA coefficient, the more resistant the foam and conversely, the lower the coefficient, the softer the foam.

• Resilience: It will represent the capacity of the mattress to return to its initial shape after being compressed; it depends on the elastic properties of the material.

Therefore, the density, KPAs and resilience of the foam are essential criteria when buying a mattress.

A flexible foam (HR) will generally be more elastic, and will have little firmness, it has an instantaneous reaction (resilience). She follows the movements perfectly.

A viscoelastic foam (shape memory) is a foam with slow resilience, that is to say that it takes time to regain its initial shape after movement and can sometimes appear firm and inelastic on first contact. This foam is specially designed to follow the shape of the body and adapt to the morphology . Sleepers can then enjoy a cocoon effect.

These differences are related to the structure of the foam . The "aeration bubbles" are more open on soft foam, hence their elasticity, and more closed for viscoelastic foam. When the air contained in the "bubbles" circulates more difficultly, this gives the shape memory aspect, until the foam regains all its swelling.

Find the 3 Bdreams mattresses made of High Resilience and Viscoelastic foams on our site and choose the comfort best suited to your needs: mattress category