Memory foam mattresses are a relatively new development in the luxury bedding market, only having been out for a little over 10 years now. Most people grew up sleeping on an innerspring mattress and are familiar with their construction and feel. But the make up of memory foam beds is a new consideration and it makes comparison shopping difficult for first time consumers.
Different mattress makers are building their beds with different configurations of foam, and everyone says their way is the best. There are many innovative construction techniques that contribute to some really nice foam beds. However there are other constructions that don't have value, but get perpetuated in the marketplace because everyone is following the sales leaders.
One construction technique that has no value, but a lot of mattress makers are using it, is the convoluted airflow layer. A convoluted airflow layer is simply a layer of polyurethane base foam (not memory foam) that has been run through a convoluting machine to give it a ripple or wave pattern. This base foam layer is placed below the memory foam layer for the purpose of creating airflow channels to vent heat away from the body.
The convoluted airflow layer is the supposed to be the answer to memory foam overheating. In fact one of the biggest complaints about memory foam beds is that they get too hot for some people. So, manufacturers experimented with convoluted foam to see if it would help keep the mattress cool. The idea is that it will allow air to circulate along through the open spaces, replacing warm air near your body with cooler air from outside the mattress. They found that the convoluted layer didn't help keep the bed cool at all, but customers liked the idea of it, and this helped sell more beds.
Reasons to Be Skeptical of Convoluted Airflow Layers
First, memory foam beds are at least 2 layers of foam laminated (glued) together. If the bed has a convoluted layer, then this adds a third layer. Other layers can include super soft pillow top layers on top of the bed and base layers of different firmness. When a memory foam layer is glued on top of a convoluted layer, the convoluted bumps flatten out and stick to the bottom of the memory foam layer. The edges of the convoluted layer are not glued, so from the outside of the mattress, it still looks like it might work. But if you were to look at a cross section cutaway from the bed, you would see that no air could possibly squeeze through.
Second, even if the airflow layer was not glued (as in a component bed), the convolutions or channels would not circulate a significant amount of air (if any at all). The sides of the bed, where the outside air would be pulled into the mattress are covered first by the mattress cover, then by the sheets, then by the blankets, comforter, etc. Certainly it's not an ideal ventilation system.
Third, there are no studies to back up the assertion that airflow layers work. One could be done simply. In fact, there is an airflow study that is commonly done to check the airflow of open cell foam.