Tobias Roberts
Memory Foam Mattress
When it comes to mattresses, resilient memory foam has taken the world by storm since its introduction in the early 90s. These mattresses, made of the familiar and versatile polymer polyurethane, are specifically viscoelastic and slowly mold to the body due to pressure and heat. This low-resistance foam ranges in form depending on what compounds and additives are in the polyurethane. These chemicals change the viscosity and elasticity of the memory foam. In this instance, "viscosity" is how long the foam takes to change its shape under pressure, and "elasticity" is its ability to stretch while still returning to its original condition.
A standard foam mattress will have three layers of foam, each serving a different purpose.
- Comfort Layers are at the top of the mattresses, designed to promote cushioning and contour. This factor will change depending on mattress firmness. The intent of this section of foam is often to be breathable and transfer heat away from the surface.
- Transition Layers are placed between the comfort and core layers and are traditionally firmer than the comfort layer. The foam of this layer is better able to wick away heat from the comfort layer.
- Core Layer foam is the foam at the mattress base and is the firmest mattress layer. This layer provides support to the mattress as well as stability through the two additional foam layers.
When exploring which memory foam mattress is appropriate for you, it pays to know a little more about the foam that goes into the mattress layers. Of the beds on the market, there are three primary memory foam types:
- Traditional memory foam molds to your body and has the standard three foam layers (comfort, transition, and core). As the memory foam uses your body heat to form the bed to a comfortable fit, traditional memory foam tends to retain the heat, making them uncomfortably warm.
- Open-cell mattresses contain memory foam filled with internal pockets that allow for increased ventilation and airflow. These "open-cells" allow for better dispersal of heat at the cost of firmness and support. Many modern foam mattresses have addressed this issue, leading to foam mattresses with both structure and cooling.
- Gel foam mattresses are another option to consider. The success of these mattresses comes from filling the foam layers with gel microbeads. This gel will generally contain a "phase-changing" material that will absorb heat from the body and release it, making this one of the coolest mattresses.
Beyond what foams makeup, foam mattresses have a few other features to consider:
- The Firmness of a foam mattress will vary, ranging from very soft (1) to very firm (10) on the firmness scale. Suppose you're looking for a more detailed report of firmness. In that case, the Indentation Load Deflection (ILD) measures firmness across each mattress layer, providing individual foam layer scores and a total mattress score.
- The Density of a foam mattress concerns how much foam is present in each layer. The metric for this is pounds per cubic foot (PCF). A higher density foam will often hold its shape, elasticity, and support longer than low-density alternatives. The downside is with a higher density is that they typically sleep hotter. If you're a hot sleeper but still want a dense bed, consider a foam mattress with a PCF of 3.0-5.0.
- The Thickness of the mattress is the measurement of the mattress side, with thicker mattresses being typically a softer, more supportive option than thinner foam mattresses. Thickness doesn't just relate to the mattress as a whole but also the individual layers (comfort, transition, and core). Traditionally, a foam mattress should contain four inches of separation foam between the mattress base (core layer) and the sleeping surface (comfort and transition layers). This thickness is to ensure good support.
With the knowledge of the various foam mattress types and other features to look for, the final step is to find a mattress with a Certipur-US certification. With this seal of approval, you ensure that your foam lacks select chemicals found to be harmful to both the foam mattress and your health.
While, in recent years, there has been a push to develop more eco-friendly memory foam, the majority of mattresses today are polyurethane. The process of creating these mattresses is energy heavy, producing a decent carbon footprint. In addition, the recycling process of these mattresses is still imperfect, with numerous foam mattresses still finding their way to the landfill. Suppose you're still looking to purchase a memory foam mattress. In that case, a higher quality mattress is likely more sustainable than a lower quality alternative. The reasoning for this is because lower-quality memory foam mattresses often include additives that will degrade the material, shortening the lifespan. These products can potentially cause skin irritation in addition to the standard off-gassing. Off-gassing is common in all memory foam mattresses, releasing VOCs and odors typically gone within 24 hours. These can last longer with cheaper foam mattresses, which have extended off-gassing periods. If you want to ensure your memory foam mattress is safe, look for a Certipur-US certification, which denotes that a foam mattress is free of harmful chemicals.
Memory foam was initially designed in the 1960s for NASA as spaceship seats and seatbelts.