Latex mattresses

Thousands of mattress shoppers come to this site every month to learn about the kinds, brands and models of mattresses available. Over 1,500 visitors have taken our poll, and more than 18¼ percent prefer latex mattresses. More still prefer memory foam (38.7%) and innerspring (26%) mattresses, but the popularity of latex is growing. According to the poll, latex mattresses were preferred by more readers than air beds and water beds combined. There are even a few mattress manufacturers, such as Pure Latex Bliss, which focus on this category.

As with innerspring and memory foam beds, there are many varieties of latex mattresses. As each type of mattress has its own advantages or disadvantages, so does each brand and model of latex mattress. Currently, at least 35 latex mattresses are reviewed on this site, not counting hybrids with latex. Some memory foam mattresses have latex support cores. At this time we need customer reviews for latex mattresses.

What are the key advantages of latex?

Characteristics of latex which almost all mattress manufacturers count as advantages are resiliency, resistance to microbes, dust mites, and mold, durability, and breathability. In the middle of the 20th Century, latex began to be used for marine mattresses due to its resistance to mold and mildew. Natural latex, also called natural rubber or foam rubber, is biodegradable. When properly washed during processing, latex is generally hypo-allergenic. I say “generally” because even then there are individuals who are allergic to latex.

How is latex made?

Natural latex (or rubber) is made from the sap (latex fluid) of the Brazilian rubber tree (Hevea brasiliensis). Rubber is made by vulcanizing the latex. Latex for bedding is also vulcanized, though not in exactly the same way. It is usually cured as a foam (though a few mattress support cores are solid latex). Latex for mattresses and pillows is made by one of two processes: Dunlop or Talalay. The Dunlop process is the simpler and less costly. Latex is allowed to solidify in a heated mold. Talalay processing seals the mold, applies a vacuum, then freezes the latex. The frozen latex is gradually heated and cured. The advantage of the latter process is that the latex is evenly distributed with the same density throughout. Dunlop latex tends to be denser toward the bottom, making it suitable for support cores.

Not all latex is 100% natural. Before World War II, synthetic rubber was invented, combining butadiene and styrene. Later, this was used to make synthetic latex foam. Now, according to standardized terminology, “all natural latex” is 100% tree sap, “natural latex” is a blend of mostly tree sap with butadiene, and “synthetic latex” is all or almost all synthetic. This is no guarantee that these definitions will be strictly adhered to; some copywriters are more particular about this than others.

Latex is available in a wide range of densities and firmness levels. Latex foam can be made to be as conformable as memory foam, making some latex mattresses comparable to the best memory foam mattress.

Here are some the key points needed to determine which latex mattress is best:

Firmness – The firmness of a mattress–or mattress materials–is measured by Impression Load Deflection (ILD), the amount of weight needed to indent a 50 square inch circle by 1 inch. The higher the ILD, the firmer the material. The firmness of a mattress is a composite of all the materials and how they are arranged. Most mattresses are softer at the surface and firmer in the core. Some two-sided (flippable) mattresses have different firmness levels on opposite sides. In this case the user can change how firm the mattress is by turning it over.

The firmness of the mattress as a whole relates to how well it supports you. If it is too soft, it tends to sag and let the spine sag too. This leads to back problems. But if it too firm, it feels hard and can create soreness and pain, especially of the wider parts of the body such as hips and shoulders, even elbows, knees and feet.

The scale of firmness used on is 1-10, with 1 being the softest. Firmness is subjective, feeling different to separate individuals. For instance, a medium firmness mattress may feel hard to a very light person, but soft to a very heavy one. Obviously, heavy people need more support. Therefore, the results of a poll or several reviews has to be taken as the average of the entire pool of responders. You, as the consumer, need to see how the mattress feels to you over a long enough period of time. This is why many mattress companies have sleep trial periods ranging from 30 to 120 days (or nights).

Weight – On product descriptions, the “weight” of latex foam measures its density. Density tells how much a certain volume weighs. In the United States, this is given as pounds per cubic foot (1 cubic foot equals the volume of a cube 1 foot in each dimension). In a multiple-layer mattress, the weight of the material in each layer may be given. An overall weight is not usually listed, but if it were it would have to calculate not only the density of each layer, but have to take into account the relative thickness of each layer, a rather complicated computation. If a layer in a latex mattress is zoned, this means that sections of the foam are either thicker or firmer than other sections of the layer

Resilience (Bounce Back) – Resilience is how the foam, coils or other material springs back. This can be measured by the time it takes to return to its original form. It can be confused with resistance: how much pressure it takes to depress the material to a certain point and how long it takes to reach that point. Even though latex can be made as conformable as memory foam, it is more resilient. It returns to its original form almost instantly, whereas memory foam leaves an impression lasting several seconds. Being more resilient means that it is easier for the sleeper to change position, making a new impression, an advantage for light sleepers.

Airflow – Most mattress makers today tout airflow as a feature of their products. For instance, Simmons Beautyrest advertises its AirCool Design, a system of open cell foams, perforated foams, ventilated foam encasement and a mesh border, engineered for air to circulate into, within, through, and out of the mattress. Why the airflow? Coolness and freshness. Air circulating though the mattress carries heat away from the sleeping surface. Eventually, this heat dissipates into the room’s air. Circulating air also helps keep the mattress fresh, removing odors and keeping them from building up. It also keeps the mattress dry.

Outgassing – Outgassing is usually not a problem with latex foam mattresses, especially the all natural ones. Even synthetic latex usually does not usually outgas, since it is washed after molding. However, if the support core is polyurethane, there may be some gassing.

Layers – Not all layers are the same, though a latex mattress may have two or more identical layers. Layers in a foam mattress are listed as support or comfort. The support core is usually one prime layer (the thickest in that mattress) with a base layer or pad below. It may also have an insulator or transition layer above, between it and the comfort core.

The primary support layer is not only the thickest, but also the firmest one. This support is not only for the user, but also for the comfort layers above. Its role of underlying support is vital for spinal health and comfort, more so when the top layers are very soft. Keeping these layers from bottoming out is good for the sleeper’s health and makes the comfort layer(s) last longer.

The comfort layers of a latex mattress mediate the firmness of the support layer for the comfort of whoever is lying on it. Usually the layers become progressively softer toward the top. But sometimes the order of firmness levels is changed. This way the mattress can be ultra plush and still provide orthopedic support. One advantage of multiple layers is the comfort level can be finely tuned. Another is that different materials can be used in different layers to achieve various effects. Also, the multiple interfaces between layers is said to make them less likely to bottom out.

Warranty – Warranties for foam mattresses and innerspring mattresses with foam comfort layers spell out how much of a permanent indentation defines sagging. This is understandable, since a small amount of lasting impression is naturally expected in these materials, and latex is no exception. Mattress warranties are written to cover design, materials and manufacturing defects, not wear due to natural usage. Conditions for the warranty are usually quite specific, requiring certain kinds of support for the mattress. Stains can void most warranties. The reason is simple. Stains usually indicate that a substance soaked the cover and possibly went into the mattress. Many liquids can cause metal coils to corrode and foams to deteriorate or degrade, and this can compromise the bed’s support.

Warranties on latex mattresses range from 10 to 25 years. Some are non-prorated, especially for part of the coverage. However, bedding industry news articles report that major manufacturers, such as Tempur-Sealy, are covering most of their newest lines of all types of mattresses for only 10 years. Latex, on the whole, rivals most metal springs for durability, and it is generally more durable than memory foam. Therefore, it earns a long warranty period.

After considering all of these key points—firmness, weight, resilience, airflow, outgassing, layers and warranty—what makes a latex mattress better for you is how it works for you?

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