Polyurethane foam (also known as polyfoam), memory foam (also known as viscoelastic polyurethane foam or tempurpedic foam) and latex foam are the three most common types of foam used in mattresses in the U.S.
Polyfoam is the lowest quality and least expensive foam used in mattress toppers and mattresses. Polyfoam is essentially made up of compounds derived from petrochemicals.
Often, mattress manufacturers use polyfoam as the top layer of spring coils mattresses. This is done chiefly because polyfoam is inexpensive, not because it’s high quality. More recently, many online mattress retailers have begun using polyfoam as a base layer in their mattresses instead of using spring coils. Polyfoam can be easily compressed due to its low density. This allows many online mattress retailers (bed-in-a-box) to save on shipping costs but also causes many of these mattresses to have relatively shorter lifespans.
There are several different densities and varieties of polyfoam. Generally, higher density polyfoam is a bit more durable while low-density polyfoam can degrade very quickly (sometimes within one year). Even high-density polyurethane foam is less dense than memory foam or latex foam. All polyfoam, no matter what its density, will degrade faster than any latex foam of reasonable quality.
Polyfoam can add some support and softness, but it won’t provide the same support associated with latex foam or memory foam. Polyfoam tends to collapse much quicker when pressure is applied to it. Therefore, it doesn’t provide the same contoured support that latex foam is well-known for.
Polyfoam rarely carries any emission certifications other than the Certipur-US certification. While this certification is an important step in the right direction for the polyfoam industry, it lacks the credibility of third party certifications such as Oeko-tex or eco-Insitut. While the Certipur-US certification does ban the use of certain types of fire retardant chemicals, it’s quite common for polyfoam to contain fire retardant additives. Furthermore, this standard is administered by the polyfoam industry itself.
Memory foam is a type of polyurethane foam that contains added compounds which change the way it feels, and gives it the slow moving properties that it’s known for. For instance, it’ll hold your hand print for a few seconds when pressed. As with polyurethane foam, memory foam is also made up of compounds derived from petrochemicals.
Memory foam is usually more expensive and denser than regular polyfoam. Memory foam provides a more pinpointed feel than polyfoam, but it isn’t as supportive as latex foam. Unlike latex foam, which provides constant support and responds instantly, memory foam sinks further and responds slowly, the longer such pressure is applied to it. The sinking of memory foam contributes to moving during sleep more necessary, but the slow response of this type of foam makes it difficult to move without sleep being disturbed.
Memory foam is also heat reactive, meaning that it absorbs heat and softens as it gets warmer. This adds to the sinking issues mentioned above. As the memory foam heats up from your body, it gets softer and sinks more. As your body sinks further into the foam, you’ll get hotter. This carries on until you wake up to find yourself hot and probably stuck in one spot of your mattress.
More recent versions of memory foam exist, which are designed to reduce such heat (often called gel-infused foam). While these new foams contain chemicals which make the surface of the foam feel cooler, many experience the same heat issues with it.
Densities of memory foam may vary greatly. In general, higher density memory foam is of better quality and more durable. There are lots of low density, inexpensive memory foam toppers being sold online. Many mattresses also contain this low density, cheaper memory foam. Low density memory foam will degrade very quickly (sometimes within less than one year after purchase).
As with polyfoam, Certipur-US is often the only certification that is applied to memory foam. Memory foam is also commonly made with fire retardant chemicals.
Latex foam is a foam produced by vulcanizing liquid latex into a solid foam. Such vulcanization process links latex particles with sulfur through the application of heat and accelerators such as zinc oxide. Latex foam can be produced with synthetic latex, which is produced from petrochemicals, or natural latex, which is harvested directly from rubber trees.
Latex foam reacts instantly to every move of yours and provides exact pinpointed support. Latex foam does not sink in and bottom out as the sleep progresses. It doesn’t get softer when warmer and maintains constant support. This characteristic makes it extremely easy to move in bed throughout the night without any sleep disturbance. The contoured support allows certain areas of the body to sink further into the mattress while others are supported. This is especially helpful for side sleepers, as they require more support in their midsection, but more give in their shoulders and hips.
Latex foam is the most durable type of foam available. Latex mattress toppers and mattresses long outlast those made with polyfoam and memory foam. Latex foam scores highly on all foam durability tests which simulate long periods of use (20+ years).
It is very common for natural latex foam to have emissions certifications, e.g. eco-Institut and Oeko-tex class 1 certified. While synthetic latex foam can also have certifications, it isn’t as common.
Latex foam is probably the best type of foam to use in mattress toppers and mattresses. Latex foam offers several significant advantages over memory foam and polyfoam.