Mattress Comfort Layers

Last updated on

Introduction

The comfort layers of a mattress provide cushioning, aid in pain and pressure relief, and serve as protective buffers between you and the internal support core, or mattress core. Innerspring mattresses usually have basic top and bottom comfort layers surrounding the internal spring core, while foam and hybrid mattresses feature multiple levels of padding and foam throughout the comfort layer for additional cushioning. The comfort layer in most mattresses is a few inches thick, and consists of three distinct parts. The largest component, known as the middle upholstery, is made of soft and supportive material to provide sleeper comfort. The innermost part, the insulator, separates the middle upholstery from the core. And the topmost component, quilting, adds an extra layer of comfort for the sleeper. Today’s mattresses fall into three general comfort layer categories. Progressive models feature a thinner comfort layer that works in tandem with the mattress core to offer body-specific support. Differential mattresses have thick comfort layers that provide cushioning without the core. And zoned mattresses feature multiple comfort layers strategically placed to cushion certain areas of the body. This article will discuss some of the most common materials and construction methods used in mattress comfort layers. For more information about internal mattress construction, check out our post about mattress support cores.

Latex

Latex is considered one of the highest quality mattress components

Latex is a soft yet durable material derived from the sap of the Hevea brasiliensis, more commonly known as the rubber tree. The latex used in mattresses is usually a blended composite of natural latex (or NR) latex and synthetic (or SBR) latex, which is made of petroleum-based plasticizers and other petrochemicals. Mattresses that do not contain any synthetic materials, pesticides, herbicides or other manmade components are considered 100% organic and can be classified as such by the U.S. Department of Agriculture (USDA). This label is different from 100% natural latex, which may contain a small percentage of synthetic ingredients.

The ratio of NR to SBR latex in a comfort layer often correlates with both the price and overall quality of a mattress. Models with higher amounts of NR latex are more resilient and comfortable for sleeping, and thus tend to be more expensive.

Two different processes are used to produce latex. The Dunlop process (used for more than 80 years) requires the rubber tree sap to be stirred, molded and steam-baked, causing natural sediment to collect at the bottom. The result is latex that is dense, heavier and more sturdy. In contrast, the relatively new Talalay process involves placing the molded sap in a vacuum-sealed chamber, where it is deprived of air, frozen and finally baked. Compared to Dunlop foams, Talalay latex has a more homogenous consistency, making it softer and bouncier.

You can test the softness or firmness of a latex mattress by measuring the impression load deflection, or ILD; this term may be used interchangeably with impression force deflection, or IFD. To measure ILD, set a circular metal disk with a 1-foot diameter onto a section of latex that is roughly four inches thick. The ILD measurement will be the amount of load (weight) or force needed to compress the foam by 25%. ILD ratings range from ‘firm’ (high) to ‘soft’ (low), and are expressed in numerical measurements. ILD should not be confused with mattress density, which is an object’s mass divided by its volume; density measures mattress foam qualities like durability and support, and is typically used to evaluate polyfoam mattresses (see next section).

The following table looks at the general ILD rating categories for latex mattresses. Please note that some numerical ILD measurements aren’t listed on the table because they are considered ‘middle ground’ ratings between two categories. A latex mattress with an ILD of 28, for instance, is considered too firm for the ‘medium’ designation and too soft for the ‘medium-firm’ designation. Generally, Talalay latex will usually have a lower ILD rating than Dunlop foam.

CategoryILD MeasurementFoam Characteristics
Soft19-21Mattress sinks considerably beneath most sleepers
Medium24-26Balances softness and firmness to a fairly even degree
Medium-Firm29-31Firm support with almost no sinking
Firm34-36Completely firm with no sinking whatsoever

Latex is considered a high-quality comfort layer material because it will conform around your hips, shoulders and contours. This alleviates pressure points and supports your spinal alignment. This is especially beneficial for people with chronic back and joint pain, as well as side sleepers, who need more cushioning in their midsection. And due to the natural durability of latex, the material will offer proper support and comfort for years ― more than a decade, in some cases. In latex with a low ILD, you may need to continually rotate the mattress in order to restore your sleep surface to its original shape.

Motion isolation is another property of many latex mattresses. This term (also called motion transfer) refers to how much movement can be detected from one side of the mattress to the other. If your partner tosses and turns in their sleep, then sleeping on a mattress designed for motion isolation means you won’t be able to feel their movement from your side of the bed.

The smell of latex is also considered a perk by many users. Some mattress materials are prone to off-gassing, a reaction that occurs after the breakdown of substances called volatile organic compounds, or VOCs. Off-gassing produces a pungent, often unpleasant odor. Synthetic latex is known to produce some off-gassing, while organic and natural latex produces little to no off-gassing. Due to the low VOC levels, natural latex often receives green certification from third-party eco-labels like Oeko-Tex 100 and Eco Institut, as well as industry-oriented eco-labels like CertiPUR-US® certification (see the next section for more information about these certifications).

However, there are some known drawbacks to latex. One is poor heat retention; many report that latex sleeps hot, causing discomfort during the night―although natural and organic latex is considered more breathable. Cost may also be an issue for some mattress buyers, since mattresses with latex comfort layers tend to carry the heftiest price tags. Expect to pay at least $900 to $1,200, although the average latex model will cost roughly $2,000.

If you are interested in buying a mattress with a latex comfort layer, here are a few questions to ask before finalizing your purchase:

  • What is the ratio of natural to synthetic latex? The amount of natural latex will usually dictate the comfort, lifespan and price of the mattress. The ratio also indicates the likeliness of off-gassing, since organic and natural latex causes less off-gassing than synthetic latex.
  • Which process was used to produce the latex? The Dunlop process will produce a heavier and firmer comfort layer, while the Talalay process will yield a softer comfort layer.
  • What is the ILD rating? Remember: the higher the ILD, the firmer the mattress.
 

Polyurethane Foam

Flexible polyurethane foam, also known as polyfoam, is a synthetic material derived from the reaction between two petrochemicals: polyols and isocyanates. Polyfoam is most often used to create the comfort layer in innerspring mattresses, but it may be used in foam mattresses as well. The material is also found in couch cushions, and used to make ‘egg-crate’ mattress toppers and sleeping pads.

Polyfoam is considered the lowest-quality material for comfort layers. This is primarily due to its relatively low density, which causes the material to break down and degrade much faster than other materials. As a result, body impressions will form in the mattress surface rather quickly. Due to its composition, density is the more practical way to measure polyfoam mattresses (as opposed to ILD/IFD). Three grades of polyfoam are available: high (HR), medium (HD) and low (conventional). These grades are differentiated by density, as well as compression modulus, a measurement used to determine the stress-to-strain ratio in an object when pressure is applied. The table below explores the differences between these three grades.

Polyfoam GradeTrade NameDensity (Pounds per Cubic Foot)Compression Modulus
High-gradeHR Polyfoam2.5 lbs/ft3 or higher2.4 or higher
Medium-gradeHD polyfoam1.8 to 2.5 lbs/ft32.1 to 2.3
Low-gradeConventional polyfoam1.8 lbs/ft3 or lower1.8 to 2.0

One thing to keep in mind: According to the International Association of Bedding and Furniture Law Officials (IABFLO), any mattress sold as HR polyfoam must have a density of at least 2.5 pounds and a compression modulus of at least 2.4. .

Polyfoam is soft to a degree, but it will not conform to your body or target pressure points in the same manner as latex or memory foam. If you prefer a contoured fit or have chronic back or joint pain, then you should check the polyfoam content of any mattress you’d like to buy. A good rule of thumb: avoid mattresses with more than one inch of conventional polyfoam. One thing to remember: many mattresses labeled as ‘latex’ or ‘memory foam’ contain polyfoam layers, so it’s always best to inquire about these components before you buy.

Green certification is another issue with polyfoam. Most polyfoam mattresses will carry the CertiPUR-US® certification, which is awarded by a nonprofit organization named the Alliance for Flexible Polyurethane Foam, Inc. This certification ensures the foam doesn’t contain mercury, lead, heavy metals, formaldehyde and other hazardous materials, and that the manufacturing process produces low VOC emission levels. However, CertiPUR-US® has been criticized over its connection to the polyurethane industry, and the certification does not carry the same weight as third-party or independent eco-labels like Oeko-Tex 100 or Eco Institut; these certifications are usually only awarded to natural and, in some cases, synthetic latex.

On the other hand, a polyfoam mattress will be suitable for anyone who does not have any special sleep preferences. Polyfoam is found in most mattress models, so the price will vary by brand; expect to pay between $800 and $2,000 for a polyfoam mattress, depending on the brand and the density grade.

Before buying a mattress with a polyfoam comfort layer, here are some important considerations to make:

  • What is the polyfoam grade? Conventional polyfoam may deteriorate in less than a year, while HD and HR polyfoam have longer lifespans. Remember to check the density and compression modulus of the foam to determine the grade, regardless of what the label says. Also ask about the thickness of low-grade polyfoam layers; you may want to steer clear of mattresses with conventional polyfoam layers that measure more than one inch thick.
  • What is the polyfoam content? Since polyfoam is so inexpensive, mattress manufacturers will often use the material in mattress comfort layers. This is even true of mattress models sold as ‘latex’ or ‘memory foam’.
 

Memory Foam

Memory foam (also known as viscoelastic foam) bridges the gap between polyfoam and latex. While technically a polyurethane-based material, memory foam is treated with additional chemicals for an exceptionally soft and malleable surface. Sleepers who use memory foam report a conforming fit and targeted pressure relief reminiscent of natural latex. Memory foam is widely used for mattress toppers and pillows, as well.

Memory foam is designed to conform around your figure for a customized fit.

Memory foam is engineered to respond to temperature. When you are lying on memory foam, your body heat essentially melts the foam, creating a contoured impression in the mattress than can help spinal alignment and relieve pressure points. Then, once you get up, the mattress will cool and become firmer as the memory foam retains its original shape. Mattresses known as memory foam hybrids are designed with both an innerspring and memory foam layers measuring at least two inches in height. Hybrid options are suitable for sleepers who enjoy memory foam’s conforming qualities but also prefer to sleep on an innerspring.

Many varieties of memory foam are available on the market. Most mattresses feature open-cell memory foam, which is designed for breathability and quick shape retention. However, some mattresses are made with closed-cell memory foam, which is firmer and less breathable. Memory foam may be marketed as ‘100% organic’ or ‘natural’ by some manufacturers and retailers, but the accuracy of these labels has been widely debunked.

Like polyfoam, memory foam is categorized into three grades. The table below features a detailed breakdown of these three categories.

GradeDensity (Pounds per Cubic Foot)Qualities
Low2.5 to 3.9 lbs/ft3Good motion isolation, some contouring and retains original shape rather quickly
Medium4.0 to 5.4 lbs/ft3Very good motion isolation, adequate contouring and retains original shape rather slowly
High5.5 lbs/ft3 and higherExcellent motion isolation, excellent contouring and retains shape very slowly

Identifying your most important criteria is key to selecting a memory foam mattress, as each grade carries noticeable perks and drawbacks. Low-density memory foam is the least expensive option, and this material will also retain its original shape in the least time. However, this grade is also characterized by middling motion isolation, poor contouring and a relatively short lifespan. Alternatively, high-density memory foam will carry a hefty price tag and is slow to retain shape, but this grade is considered the best memory foam option in terms of motion isolation, conforming and longevity. Medium-density memory foam, as the name implies, is a middle-of-the-road option that ranks between the two other density grades for virtually all criteria.

Due to its complex composition and similarities to latex, memory foam is also measured for ILD. In most memory foam mattresses sold today, the ILD ranges between 10 and 20; an ILD of 13 to 15 is considered optimal for the average sleeper. You may find some memory foam models with an ILD lower than 10, but beware: these mattresses will be too soft and prone to sinking for most people, particularly heavy-set individuals. Likewise, any memory foam mattress with an ILD of more than 20 will probably be too firm.

Reviews for memory foam mattresses are somewhat mixed. Although most users rate memory foam higher than polyfoam in terms of comfort and overall support, the material still carries a few drawbacks. One major issue is odor. Like polyfoam, memory foam can produce high levels of off-gassing. This quality is common to all three memory foam grades, although the most persistent off-gassing smells have been reported in high-density memory foam.

Memory foam is also considered significantly less durable than latex. A common complaint among long-term users is that their memory foam mattress will sag in certain places over time (depending on their sleeping position). This can cause sleeper discomfort, and in some cases may exacerbate chronic back or joint pain. Regardless of density, most memory foam mattresses have a lifespan of six to eight years; the lower the memory foam’s density, the shorter the lifespan. Premature sinking is less common in mattresses that contain thin layers of memory foam.

Finally, memory foam has been criticized for poor heat retention. Even low-density memory foam is thick enough to trap your body heat while you sleep, but ‘sleeping hot’ complaints are most commonly associated with medium- and high-density memory foam mattresses.  In recent years, memory foam infused with gel beads ― known simply as gel foam ― has become a popular alternative to traditional memory foam because it sleeps cooler. Gel foam may be a suitable option if you tend to become too hot when you sleep.

Memory foam mattresses vary considerably in terms of price. A standard memory foam model will cost anywhere from a few hundred dollars to several thousand, although most buyers pay less than $1,500 for a new mattress. Memory foam hybrids tend to be a bit costlier; you should expect to pay at least $2,000, although luxury brand models may cost more than twice that much.

If you are considering a memory foam mattress, here are a few questions to ask.

  • What is the density? The density of a memory foam mattress will affect contouring, motion isolation, heat retention, shape recovery, off-gassing levels and price. First determine which density most closely aligns with your needs and preferences, and then you can decide which brands and models will work best. Also keep in mind that memory foam mattresses with low density will have a shorter lifespan than high-density mattresses.
  • What is the ILD? Although an ILD of 13 to 15 is considered optimal, every sleeper has different preferences when its comes to softness and firmness.
  • How thick are the memory foam layers? Mattresses with thin memory foam layers are more resilient and less prone to sagging, while thick layers are associated with poor shape recovery and a short lifespan.
 

Natural Fibers

In addition to latex, other natural fibers may be included in your mattress comfort layer. These include cotton, wool, silk, horsehair and horsetail, bamboo, hemp and coconut fibers. These components are usually found in the quilting of your comfort layer ― and in some cases, more than one natural fiber will be present. Let’s look at the specific characteristics, benefits and drawbacks associated with each of these natural components.

Cotton is a natural fiber that is commonly used in mattress construction

Cotton is a popular comfort layer material due to its natural softness and breathability. Cotton is also widely available; more than 20 million tons are produced on an annual basis, and roughly 2.5% of the world’s cultivated land is used to grow it. Organic cotton is also used in mattresses as a green alternative to standard cotton, since the former is not grown with chemical fertilizers or pesticides.

Wool has been noted for year-round comfort. The naturally absorbent fibers keep you cool during the hot times of the year, and insulate from the cold when temperatures are lower. Wool is also quite stretchy ― much more so than cotton and other natural fibers ― creating a springy, flexible sleep surface. And because it resists fire and will self-extinguish flames, wool is considered a natural fire retardant. Organic wool is found in high-end mattresses, as well.

Like wool, silk is an elastic, absorbent fiber that will help regulate your temperature any time of year. For this reason, silk and wool are often found together in comfort layers.

Horsehair and horsetail mattresses are noted for their durability and bounciness ― as well as their relatively high price tag. Horsehair fibers are short, whereas horsetail fibers are quite long, but both materials achieve the same effect when used in a comfort layer.

Bamboo is one of the most prevalent plants in the world, and can be easily grown in most climates. The fibers are breathable, absorbent and naturally bouncy, but can also withstand more bodily compression than other natural or synthetic materials.

Hemp, similar to bamboo, grows quickly and can handle high levels of compression before deteriorating. The material is also naturally dense, making it ideal for heavy-set sleepers.

Coconut coir, or coconut fibers, are harvested from the fruit’s outer shell. Coconut coir is springy, absorbent and flame-resistant, and the material has also been praised for its stellar heat retention.

One common drawback links all of these natural fibers: cost. Manufacturing most natural fiber comfort layers will require additional processes and treatments to ensure they reach the right balance of softness and firmness, and can withstand high levels of compression. These extra steps effectively drive up the price, even in mattresses with small amounts of natural fibers in the quilting. Expect to pay at least $2,000 for a new mattress with significant natural fiber content, and even more for models with a high percentage of natural fiber components. The high price tag is certainly warranted with most of these mattresses, but you may be able to find a cheaper foam model that addresses all of your individual sleep needs at a much lower cost.

However, there are many perks to natural fiber comfort layers, as well. These include natural flexibility and breathability, heat resistance, absorbency, pleasant smells, eco-friendliness and a significantly longer lifespan. If you are interested in mattresses with natural fiber components in the comfort layer, be sure to try out several different varieties ― and compare prices ― in order to find your best match.

Here are some considerations to make before purchasing a natural fiber mattress.

  • Which natural fiber(s) is/are used? Every natural fiber used in mattress production carries specific benefits and drawbacks.
  • Are the natural fibers organic? Organic cotton, organic wool and other organic fibers are certified to be free of chemical fertilizers and pesticides.
  • What percentage of the comfort layer is composed of natural fibers? Some mattresses are made exclusively with natural fibers, while others contain only trace amounts. Ultimately you should select the mattress that provides the most comfort and support for you, but make sure you’re not paying too much for a mattress with low amounts of wool, silk and other natural materials.
 

Microcoils and Nanocoils

Nanocoils are usually ¾ of an inch or shorter.

Today, many mattresses are manufactured with small coils placed throughout the comfort layer. Microcoils, or mini coils, are typically one to three inches long, but can be as short as 10 millimeters in length. Nanocoils are, by definition, shorter than most microcoils; most are no longer than ¾ of an inch. By comparison, support core coils found in innerspring mattresses can be up to 10 inches in length. For this reason, microcoils and nanocoils can be placed higher in the comfort layer without causing you discomfort.

Microcoils and nanocoils are usually made from thin, flexible and durable metal wire that can easily bounce back to its original shape. In recent years, 100% natural coils have appeared on the market, as well. To ensure that you cannot feel them while you’re asleep, microcoils and nanocoils are wrapped in a thin foam or fabric layer. These components are most commonly found in foam mattresses, although some innerspring mattresses feature microcoils or nanocoils layered next to the primary support core; this is known as ‘coil-on-coil’ construction.

The number of microcoils or nanocoils in a mattress will vary; some models feature more 8,000 individual coils, and may also include as many as five individual coil layers. Each coil is designed to compress and conform based on your specific bodily dimensions, resulting in a customized fit that relieves pressure points and aids chronic pain. Mattresses with coil components usually have excellent motion isolation, as well. In some mattresses, the microcoils or nanocoils will be affixed to the seams, allowing them to move from side to side, as well as up and down. This technique, known as ‘three-way stretching’, provides even more of a contoured fit. Coil comfort layers are also designed with ventilation chambers for better air circulation, which lets you sleep cool.

Microcoil and nanocoil mattresses are considered mid-range in terms of price; models generally range between $800 and $1,200. These mattresses will cost more than most polyfoam models, but are typically cheaper than mattresses made from latex, memory foam and/or natural fibers. And thanks to the resiliency of these coils, the mattresses tend to have a longer-than-average lifespan.

Microcoil and nanocoil mattresses represent a ‘best of all worlds’ option for many mattress buyers. In addition to being durable and relatively affordable, they are also designed to conform to your dimensions, keep you cool and retain their original shape.

Here are a few important considerations with microcoil and nanocoil mattresses.

  • Microcoils or nanocoils ? The difference will be insignificant to most, but some sleepers (i.e. heavy-set individuals) may be more comfortable sleeping on nanocoils.
  • How many coils are included in the mattress? Everyone will have an optimal coil count in mind. Test out multiple models to determine the right number of microcoils or nanocoils for you.
 

Buckling Column Gel

Buckling column gel

Buckling column gel, one of the newest comfort layer materials on the market, has earned praise from both consumers and critics alike. Brothers Tony and Terry Pearce created the first buckling column gel system using a hyper-elastic polymer of their own invention; they patented the idea in the mid-1990s. As the technology has evolved, different variations of the buckling column gel system have appeared over the years.

The gel itself is a dry-polymer substance with a smooth texture and a rubbery consistency. Most brands today use gel derived from mineral oil, but other acceptable options include polyurethane, silicone, PVC or acrylic gels.

Here’s how it works: these mattresses are equipped with rows of gel-filled chambers called columns, or walls, which are located throughout the comfort layer. The columns are typically round or square, but come in a variety of shapes; a top, a bottom and at least one side wall are the three key components. The number of columns is also highly variable, and some mattresses feature more than 1,000 individual chambers.

The columns respond to compression by buckling, and will sink to different levels based on weight distribution. Columns under heavy or protruding areas like the shoulders, hips, buttocks and heels will collapse, creating a contoured impression specific to your weight. Meanwhile, the columns that do not buckle will provide support to the lumbar region and other recessed or low-compression areas of your body. The top of the columns will be covered in a non-elastic fabric or material for an extra layer of firmness between the sleeper and the gel, while the bottom will be covered in elastic fabric to enhance the effects of the buckling.

As a result, comfort layers with buckling column gel offer a highly customizable fit that targets your individual pressure points and supports your spinal alignment. The ultra-stretchy construction of the columns also ensures excellent shape retention and motion isolation. These mattresses also sleep exceptionally cool, as well.

Buckling column technology is still constantly changing. In 2013, the Pearce brothers patented their newest idea: a gel-less buckling column system composed entirely of their hyper-elastic polymer. This essentially works in the same manner as gel models; the polymer frame is so stretchy that the hollow columns will collapse or remain stiff based on your body and weight distribution. In 2016, the Pearce Brothers founded Purple, a company that today provides mattresses, toppers and other cushions that utilize the gel-less buckling system.

Many users have reported a crackling sensation when they lie down on a buckling column gel mattress. Some say the feeling is soothing and adds to the experience, while others have difficulty adjusting to it. Before purchasing a buckling column gel mattress, you should definitely test it out in person to ensure you enjoy this sensation. Otherwise a gel mattress might not be right for you.

Cost is another factor, as buckling column gel mattresses are among the most expensive on the market. intelliBED, for instance, offers buckling column models starting at $2,500. Also beware: some brands may tout ‘gel mattresses’, but in some cases these will actually be memory foam models infused with gel beads (see above). These mattresses are usually much cheaper than their buckling column gel counterparts.

If you are interested in owning a buckling column gel mattress, here are a few questions to ask before you buy:

  • Does the gel mattress have buckling columns? A memory foam mattress infused with gel is not the same as a mattress with buckling columns, but labels often omit this important distinction.
  • What shape are the columns? Although all buckling column gel mattresses operate in the same fashion, you may have a different experience depending on whether the columns are square, round, hexagonal or H-shaped. Most brands specialize in beds with the same uniform chamber shape, so you may need to seek out multiple manufacturers to compare the columns.
  • Will the crackling sensation bother me? You may have a hard time adjusting to the unique feeling of sleeping on a buckling column gel mattress. Keep this in mind if you are particular about how you sleep and what position you like.

For more information about mattress composition, please check out our guide to mattress support cores along with our mattress product database.

 
Popular Reads
Stages of Sleep and Sleep Cycles

Usually sleepers pass through five stages: 1, 2, 3, 4 ...

Parent’s Guide to Healthy Sleep

Every child needs good sleep for healthy development, growth, and ...

Mattress Reviews and Comparisons 2017 – Unbiased Sleep Product Database

The research team at Tuck has put together the most ...