What is foam density and why does it determine durability?

Is foam with a density of 50 kg/m3 suitable for a bed?

Yes, this is a very suitable density for viscoelastic (V) foam. It sits at the upper end of common standards for high-quality mattresses, which supports long lifespan and strong resistance to permanent deformation. Keep in mind, though: density alone is not everything. Elasticity and a well-designed layer setup matter just as much, like in the Osaka Air mattress or the Osaka Grid mattress.

What does T35 foam mean?

T35 is a classic polyurethane (PU) foam with a density of 35 kg/m3. The letter T refers to traditional foam with closed cells, and the number indicates the density. A higher density usually means better durability than lower-grade traditional foams, but it still does not match the quality of modern high-resilience open-cell foams marked as HR. Foams of this type are simpler technologically and typically do not provide the same bounce, airflow, and stable support as modern high-resilience foams.

What is foam density?

Foam density is a parameter that tells you how many kilograms of material are contained in one cubic meter. It mainly matters for durability and wear resistance. The better the density is chosen for the purpose, the more likely the foam is to keep its properties over time. However, density alone does not decide comfort, because comfort also depends on the foam type, its structure, and firmness. Mattresses often combine foams with different densities, and it is crucial whether the foam is traditional, viscoelastic, or high-resilience. Always look at the full set of parameters.

Is foam with a density of 30 kg/m3 good?

It depends on the foam type and where it is used. Around 30 kg/m3 can be a good value for a top comfort layer if it is high-resilience (HR) foam. In that case, it can offer comfort, responsiveness, and proper support. If we are talking about standard traditional (T) foam, that value alone does not automatically indicate high quality. For the core/base of a mattress, denser and suitably firmer foams usually work better, because they provide the stability of the whole structure.

Is T40 foam firm?

You cannot determine that from the T40 label alone. It tells you the foam type and density, not firmness. Firmness is a separate parameter, so foam with a density of 40 kg/m3 does not have to feel firm. It may be more durable than lighter traditional foams, but judging comfort and perceived firmness requires looking at other material features and the overall mattress construction.