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Mattress Glossary & Terminology


Air beds are a broad category of beds in which air is used to support the sleeper. Small motors pump air into mattress bladders to create different levels of firmness. The advantage of air beds is that you can adjust the firmness to suit you, and your partner can do the same. The disadvantages are that some of the pumps are noisy and require maintenance, and the air bladders can develop leaks. These beds are usually racetracked (see below), so spouses may not feel comfortable cuddling in the middle. The biggest names in air beds are Select Comfort™, Nautilus®, and Comfortaire®. Select Comfort™ came up with the Sleep by Number™ bed.

Body impressions are indentations in a mattress that are created when the mattress compresses over time. People may call them valleys or compressions or holes; a couple creates two. When you notice compression, it’s time to change your mattress.

Box springs are a flexible-framed surface used to support a mattress. Typically box springs are placed on top of a steel frame. The box springs raise the mattress higher off the floor. You can often replace a mattress only, without replacing the box springs, but it is important that a new mattress be placed on the proper surface. Sometimes new “box springs” are made without any springs in them. These are called foundations. Foundations, unlike flexible box springs, are rigid.

Carding is a cleaning and stretching procedure used in wool production. It is a superior process to garneting. Carding involves pulling apart the strands of wool fiber and stretching them side-by-side to achieve the cleanest and best-performing wool. All the attributes commonly applied to wool–strong, durable, good loft, aridity–are possible with wool that is well carded. The same is not true of garneted wool.

Cotton fabric (sheeting) is a soft, natural product and is excellent for clothing and bedding, materials that are close to your skin. Conventional cotton growing uses fertilizers and pesticides and the product is normally treated with fire retardants. Organic cotton is grown without chemicals, and is untreated. Beyond “organic”, the most important thing to know about cotton when you choose a mattress is the distinction between cotton fiber vs. cotton fabric.

Cotton fiber is an inferior mattress material because it absorbs moisture, is a haven for dust mites, and compresses with use. Even organic cotton fiber will still absorb moisture, compress, and attract dust mites; and it can become moldy. We use organic cotton fabric as a soft outer cover for our mattress casings, but Savvy Rest does not use any cotton fiber in its products.

Density is a measurement of the mass per unit volume. Measured and expressed in pounds per cubic foot (pcf) or kilograms per cubic meter (kg/m3), density is one of the most important of properties of foam. Density is a function of both the chemistry used to produce the foam and additives included in the foam formula. Density affects foam’s durability and support. Typically, the higher the polymer density, the better the foam will retain its original properties and provide the support and comfort it was originally designed to produce.

Dust mites are microscopic insects in the arachnid family that includes spiders, scorpions and ticks. They are a common component of house dust. Dust mites feed on dead skin that sloughs constantly from our bodies, and collect in carpets, pillows and mattresses. They can enter any porous material, including woven fabrics, with openings of 10 microns or greater. A mattress encasement or “allergy cover” with a pore diameter of less than 10 microns will block mites and their feces–the most significant mite-associated allergen. Unlike a mattress pad, an allergy covers encases the entire mattress. Although cleanliness is critical for allergen control, vacuuming or changing bedding stirs up mites into the room’s air, where they are then inhaled. In general, however, experts recommend minimizing soft, upholstered surfaces and vacuuming frequently. HEPA air filtration systems and HEPA vacuum cleaners will greatly diminish mites’ numbers.

Duvet is a French word for “cover.” A duvet can be made like a comforter, or it may have a removable cover similar to that of a pillowtop mattress.

Fiber refers to strands of material made from cotton, polyester, wool, or silk. Fiber is used extensively in mattresses. Strands of fiber trap air between them. Fiber always compresses over time.

Foundations perform a function similar to that of box springs in supporting mattresses, except that the surface is rigid rather than flexible. They normally are covered with the same quilting as the matching mattress.

Futon is a bendable, foldable mattress that will fit into an upright frame. When the frame is in upright position, it is used as a couch; when folded out, it makes a bed. Futons vary widely in price. A frame and mattress and cover can range from $200 — $1000 and up. These days some futons are very comfortable, unlike most of those made prior to year 2000.

Garneting is a process used in processing cotton or wool. It tears the material apart, cleaning from it waste and other residue. Garneting is inferior to the carding process, because in garneting, the wool fibers become tangled instead of being stretched out.

Hi-density foam is foam with a measured density greater than 1.8.

Hi-resiliency foam is also called HR Foam. It has a measured density greater than 1.8.

ILD (Indentation Load Deflection) is a measurement of foam firmness. Firmness is independent of foam density, although it is often thought that higher-density foams are firmer. It is possible to have high-density foams that are soft or low-density foams that are firm, depending on the ILD specification. ILD specification relates to comfort. It is a measurement of the surface feel of the foam. ILD is measured by indenting (compressing) a foam sample to 25 percent of its original height. The amount of force (in pounds) required to indent the foam is its 25 percent ILD measurement. The more force required, the firmer the foam. Flexible foam ILD measurements range from 10 pounds (super-soft) to about 80 pounds (very firm).

Insomnia is a sleep disorder. It refers to being unable to fall asleep or the problem of too-early waking. Everyone experiences periods of insomnia in life. If these periods are prolonged and you feel daytime sleepiness, however, it is recommended that you consult a physician.

Knockoff means a copy of the original. Kleenex® was the first company to come out with facial tissue, for example. Other companies make knockoffs of the Kleenex® brand, some good, some not so good.

Latex comes from the rubber tree, which grows only within about 700 miles of the equator. Latex is used in a wide variety of products from rubber bands to rubber gloves to mattresses.

Loft is a term used to describe the thickness of a mattress top, a duvet, a quilt, or similar item that is filled with compressible material. What creates loft is air around the strands of the filling material.

Memory foam is synonymous with visco-elastic foam. Tempur-Pedic™ was the first company to use memory foam in mattresses. Many companies have begun copying the material and using its generic name. This is an open-celled foam that responds to the weight and heat of your body and relieves pressure. It comes in many thicknesses, densities, and different levels of softness and firmness (see ILD).

Natural latex is pure and natural latex is made by processing serum collected from ducts beneath the bark of the rubber tree. The sap is harvested, processed in a centrifuge, poured into a mold, and baked. Real, non-synthetic latex is by far the most resilient material used in mattresses today. It is more resilient than any fiber or any other foam, including memory foam.

Pillowtop is a mattress with a separate little mattress on the top. This concept was introduced in the 1970s when soft waterbeds became popular. When all beds were firm, the pillowtop idea made it possible to make a firm bed with a soft top to compete with soft waterbeds. Often filled with fiber, it is common for conventional pillowtops to take body impressions and to compress. Often these body impressions are not under warranty. Pillowtop mattresses are normally sewn right to the mattress.

Platform bed is a type of bed familiar to the futon industry. A wooden frame is made with slats that go across from side to side. When you use a platform bed, you don’t need a box spring or a foundation. You can place a latex or memory foam mattress directly on the slats.

Pressure relief is the capacity of a mattress to relieve pressure on your body. Traditional mattresses produce upward pressure, while your body exerts downward pressure through gravity. Where the two meet, especially at the shoulders and hips, you can experience pain from prolonged pressure, which reduces circulation. The result can be stiffness, numbness, or soreness upon awakening. A truly pressure-relieving mattress will yield more in places where the most pressure is exerted, relieving those spots.

PureTouch™ is the brand name used by Ther-a-pedic™ for all of their pure and natural latex beds. With so many chemicals flooding the market and polluting our landfills, PureTouch™ mattresses are a welcome relief, as well as a wonderful line of natural mattresses.

Quilting is the process used to sew a cover to the top of a mattress. Quilting is done in different shapes; sometimes logos are sewn into the cover.

Racetracking is a term for using firm foam around the perimeter of a bed. Sellers of this type of bed will tell you the advantage is that you can easily sit on the side of the bed and put your socks on. True. Sometimes it is packaged as “perimeter support.” The real reason it is done is because it is cheap, and they can use less material on the core part of the bed, which is normally more expensive. Racetracking makes air beds and waterbeds less susceptible to the “wave” type of motion transfer—because there is less bed. The disadvantage is that it reduces the sleeping surface area by 15% – 25%.

Recovery time is the amount of time it takes a piece of foam to return to its original shape. Latex foam has a short recovery time, and memory foam has a long recovery time. Along with ILD, the recovery time is one of the most important factors in determining comfort.

Sealy, Simmons, and Serta are regarded as the “big three” in bedding. Together they account for more than 95% of the bedding industry in the United States. Most of this is conventional bedding for hotels, dormitories, as well as for consumers.

Silk is a very strong material made by the silkworm. If you find this material in a mattress, most likely it is a very small amount and has little effect. An all-silk mattress would require a nation of silkworms on steroids.

Sleep by Number™ is a smart marketing idea developed by Select Comfort™, the largest manufacturer of air beds today (see air beds, above). The idea is that you can adjust the level of firmness of your mattress by pumping more or less air into the bed. It works for some people, although most people find memory foam or latex more comfortable.

Spring mattresses were developed around 1900. The spring mattress revolutionized mattresses, which formerly had been made of cotton or horsehair or other materials. The steel spring created a whole different feel as well as a different manufacturing process. In the past 15 to 20 years new ways of using springs, as well as new terminology and new marketing, have helped spring mattresses hold onto the majority of the mattress market.

Swedish foam is another term trademarked by Tempur-Pedic™. It is the same as their memory foam, which they like to call Tempur® material.

Synthetic latex is sold under many different names. Because natural latex is expensive, most companies add clay and petrochemicals to their latex to make the latex go farther. These chemicals can have harmful effects in our bodies.

Talalay is a process used to manufacture latex. In the Talalay process the air bubbles in the latex are vacuumed out. This produces a consistent texture. Most manufacturers using the Talalay process add synthetic chemicals to make the latex cheaper.

Tempur® material is the memory foam that Tempur-Pedic™ uses in their mattresses. As Tempur-Pedic™ has patented the material, they have also trademarked the name so no one else can legally use the term “Tempur® material.” This foam was inventedoriginally by NASA to relieve the pressure astronauts experienced on launch and landing.

Tempur-Pedic™ refers to the company with the same name, as well as to the Tempur-Pedic™ mattress. Tempur-Pedic™ was the first company to use memory foam or visco-elastic foam in mattresses.

Tufting is a method of attaching a mattress casing, and means that the cover is sewn from the top all the way to the bottom of the mattress. Tufting keeps layers of foam from shifting inside a futon mattress. Futons are usually tufted; traditional mattresses are quilted.

Visco-elastic foam is sometimes just called “visco” and is synonymous with memory foam. Tempur-Pedic™ was the first company to use visco-elastic foam in mattresses. Many companies have copied the material and use the generic name for it. This foam is an open-cell foam that responds to the weight and heat of your body and relieves pressure. It comes in many thicknesses, densities, and different levels of softness and firmness (see ILD).

Warranty is a statement by a manufacturer that your mattress will retain certain qualities over a certain period of time, and what they will do about it if it fails. Although it may be relevant, warranties are largely marketing techniques. Sometimes warranties cover only “defects in materials and workmanship.” Sometimes they cover body impressions, sometimes not. Warranties are either full, meaning that they will replace the entire mattress; or they are pro-rated, meaning that you will bear part of the cost of the replacement. Warranties are written to read as if they protect you. They are written by the manufacturer, however, and are designed to help sell the most product at the least cost over the long term.

Waterbed is a category of bed that became popular in the 1970s and took over 20% of the mattress market. Waterbeds altered for good the public perception that “firmer is better,” a myth generated by the mattress industry early on. Waterbeds now own a very small market percentage because of the entry of airbeds and a variety of foams, and because of problems with leaks and pumps.

Wool is the fiber or yarn made from the fleece of sheep. Some manufacturers say that wool is a supreme product for bedding because it keeps you cooler in the summer and warmer in the winter. It’s cooler in the summer because it wicks moisture and it’s warmer in the winter because it insulates. Its natural lanolin coating is repellent to dust mites.

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