What Are Gel Mattresses?
The 'Cool' New Material in Your Mattress

Gel is most often touted in mattresses for its cooling qualities, but it can offer several other characteristics, such as enhanced pressure relief, unique support characteristics, and extended durability.

From a scientific standpoint, gel is a material that falls somewhere between a solid and a liquid. Known as a 'viscous semi-rigid solid,' gel chemically resembles a liquid but exhibits no 'flow' when in a steady state.  This means it has the ability to be stretched, squished and pulled, but will always return to its original shape. Gel is similar to rubber, but it tends to be heavier and have more of a delayed resiliency than rubber. Because of these qualities, gel is a great material for shock absorption and pressure relief in mattresses.

What is the Difference Between a Gel Mattress and a Memory Foam Mattress?

Gel and memory foam are two different materials. However, they can be, and often are, combined. Both can have pressure relieving properties, depending on how they are used in a mattress.

There are three gel construction types most commonly seen in mattresses today:

Gel-infused memory foam.  The most prevalent usage of gel in today’s mattresses is gel-infused foam. Requiring a lower amount of gel than other gel mattress construction types, this approach involves mixing small flecks of gel into a layer of foam. Technically, this can be done with any kind of foam, however it is most often seen with open-cell foams such visco-elastic foam (resulting in gel memory foam) or Talalay latex (resulting in gel latex).  The use of open cell foams creates additional ventilation around the gel, which works in concert with the cooling effect of the gel.

Below: Gel flecks are visible in the top layer of memory foam

Collapsible column (or “honeycomb”) construction.  Some mattresses (significantly Purple) utilize a layer of collapsible gel columns in their beds. In this approach, thin vertical 'walls' of gel are inter-connected in a square or hexagonal pattern across the bed, so that when viewed from above, this layer resembles a grid or honeycomb. This structure is most well-known for its unique support characteristics. In order to maintain proper spinal alignment, a mattress needs to allow our curvy parts to sink deeper into the bed (but not too deep!), while still providing adequate support for the rest of our body. 

Collapsible gel columns have a unique property known as non-linear resistance – meaning that once a certain amount pressure is applied, the columns stop providing resistance and completely collapse.  This allows our heavy or protruding parts, such as the hips and shoulders, to sink down to the bottom of this layer, while our lighter or more concave parts are still supported on top.  For maximum spinal alignment, a layer of collapsible column gel is typically about 2 inches tall, which is the average amount of 'curve' that our bodies have between our hips and our waist.

Below: 'Honeycomb' gel layer of a Purple mattress

Solid gel layer.  Perhaps the most recent innovation in gel mattresses is the use of a solid layer of gel at or near the top of the mattress, or on top of a pillow.  Given the weight and density of gel, this layer is usually less than 1" thick.  That said, depending on the softness of the gel, a solid gel layer can give the mattress or pillow a very unique yet familiar feel – similar to a gel bicycle seat or gel insoles.  For those that tend to sleep hot, a solid layer of gel offers the maximum gel surface area, so the cooling effects of the gel should feel very pronounced. This style of gel mattress tends to use the most gel (by weight), so the coolness of the gel can last longer into the night.

Below: Thin layer of solid gel on top of a pillow

Do Gel Mattresses Keep You Cool?

Gel is most commonly promoted by mattress companies as a solution for "sleeping hot."  So, is gel really "cooler" than other materials?  Well, technically no – but it does feel cooler. The reason is that gel is a conductor, like water or metal. Because our bodies are generally much warmer than the ambient temperature of our bedroom, the gel's conductive properties act to 'pull' this excess heat away from our bodies, making us feel cooler.

To better understand what this means and how it works, think first about sitting in a bedroom that is room temperature (~72° F). Now think about sitting in a swimming pool that is 72° F.  Which one feels cooler? Of course, the pool feels much cooler!! This is because our body temperature is much warmer than 72° F (the surface of our bodies is normally ~90° F), and the water (an excellent conductor) allows this excess heat to travel away from our bodies very efficiently, making us feel cooler.

How much cooling do you really get from a gel mattress?

The amount of cooling provided by the gel depends mostly on three key factors:

• How close the gel is to your body.  The cooling power of the gel is based on its conductive properties, so layers of other materials between you and the gel tend to act like insulators, reducing the transfer of heat from your body to the gel.  This means that minimizing such layers – e.g., additional padding above the gel, mattress protector, thick sheets, and even pajamas! – will maximize the cooling effect of the gel.
• How much gel there is.  The more gel there is, the longer it will take your body to warm the gel from room temperature to body temperature, after which the gel will cease to feel cool.  Beds with less gel are generally designed to remain cool for 15-30 minutes – long enough for you to fall asleep, but perhaps not long enough to remain cool throughout the entire night.  Beds with thick layers of gel (e.g., 50-100 pounds of gel in a queen-size mattress) are designed to remain cool for several hours or more.
• How the gel is constructed.  Because gel itself does not allow air to flow through it, layers of gel in a mattress are often structured in such a way as to enable or create air flow.  With gel-infused foam, an open-cell foam is typically used to create added ventilation.  With collapsible columns, the hollow columns allow plenty of air circulation.  And with solid gel, channels are typically carved in the gel (giving the gel a waffle iron appearance) to enable air flow along the gel’s surface. 

How Long Do Gel Mattresses Last?

In general, gel is considered to be among the most durable materials used in mattresses today. As a semi-rigid solid, it should not lose its shape or its flexibility over time. That being said, the gel used in mattresses can be made from either polyurethane or plastic. Because plastics are known to become brittle with age, polyurethane-based gels are more desirable from a durability perspective.

It should also be noted that in the case of gel-infused foams, the gel represents a relatively small portion of that material. As such, the durability of that type of material will have much more to do with the quality of the foam that is used than with the gel that is mixed into the foam.

Gel Mattress Brands

Thanks in large part to the breakout popularity of the iComfort mattress line from Serta, including the iComfort Blue 100, there are now many manufacturers that have either created a special line of gel mattresses or added gel as a feature to their existing lines. 

In addition, there are several smaller manufacturers that specialize entirely in gel mattresses, some of which have been working with gel as a mattress material for decades. Purple is the best known example. GoodBed has reviewed the original Purple mattress, as well as the Purple 2/3/4 line, all of which use a wide layer of honeycomb gel.

Most commonly, you will see gel incorporated into memory foam and used as one of the comfort layers of a mattress. Examples include the Bear mattress, the GhostBed Luxe bed, and the Lull mattress.