Memory foam and polyfoam are both polyurethane-based, but response, pressure relief, density and layer role differ. Learn what the labels mean.
Memory foam is viscoelastic polyurethane foam; polyfoam is the broad conventional polyurethane family used throughout mattresses. The useful comparison is not “good versus cheap.” It is how a particular formulation responds, where the layer sits, and whether its density and firmness are disclosed.
| Property | Memory foam | Conventional polyfoam |
|---|---|---|
| Response | Slow to recover in many formulations | Usually faster and springier |
| Pressure relief | Strong contouring tendency | Ranges from plush to firm |
| Common use | Comfort layer | Quilting, comfort, transition and base |
| Key specs | Density, thickness, temperature response | Density, IFD, thickness, support factor |
They share a chemistry family
Both are flexible polyurethane foams. Memory foam adds viscoelastic behavior: it responds over time and often softens with heat. “Polyfoam” covers a much wider range, from soft quilt foam to high-resilience support foam.
Density comparisons need context
A memory-foam density and a support-polyfoam density are not equivalent quality grades. Compare within the material family and layer role. See foam density explained before treating one number as a verdict.
Feel comes from response and IFD
Slow response creates the familiar hug and strong motion absorption. Faster polyfoam makes movement easier and can improve responsiveness. Neither term supplies an IFD value, so the label alone does not establish firmness.
Why mattresses combine them
A common stack uses memory foam for pressure relief, firmer polyfoam for transition, and dense polyfoam or coils for support. The question is whether each layer is thick and robust enough for its task.
How to compare two foam mattresses
Start with the layer stack: ask for each layer’s material, thickness, position and density if available. A memory-foam comfort layer over a conventional polyfoam core is a common combination; a mattress described simply as “memory foam” does not necessarily use it throughout.
Compare specifications for the same material family and layer role. Density describes mass per volume and can be one durability clue; it is not a firmness score. IFD describes a sample’s resistance to indentation under a stated test method, but the feel of the complete mattress also depends on the layers above and below it.
When trying a mattress, lie in your usual position and change positions. Notice whether you prefer a close contour or a quicker response, and whether your shoulder and hip feel comfortable. Couples can compare movement and edge stability together. The room, bedding and cover can also influence temperature, so a foam label alone cannot predict whether a bed will sleep cool.
If details are unavailable, ask the seller rather than inferring foam density from total mattress weight. Check the support requirements and the actual seller’s trial, delivery and return terms before ordering.
Related construction guides
For short definitions, use the Yawnder sleep glossary. For measured performance, see how we test and score mattresses.
Frequently asked questions
Is polyfoam the same as memory foam?
Memory foam is a viscoelastic type of polyurethane foam. Conventional polyfoam lacks that same slow, temperature-sensitive response.
Which is more durable?
Density, formulation and use determine durability. A high-spec support polyfoam can outlast a low-density memory foam.
Which is cooler?
Fast-response, open-cell polyfoam often feels less enveloping, but airflow and temperature also depend on thickness, cover and the support core.
Which isolates motion better?
Slow-response memory foam usually absorbs motion well, but measured performance of the complete mattress is more useful than material labels alone.