Early mattresses contained a variety of materials including straw, feathers or horse hair. In the first half of the 20th century, a typical mattress sold in North America had an innerspring core and cotton batting or fiberfill. Modern mattresses usually contain either an inner spring core or materials such as latex or other flexible polyurethane foams. Other fill components include insulator pads over the coils that prevent the bed's upholstery layers from cupping down into the innerspring, as well as polyester fiberfill in the bed's top upholstery layers. In 1899 James Marshall introduced the first individually wrapped pocketed spring coil mattress.
In North America the typical mattress sold today is an innerspring; however there is increasing interest in all-foam beds and so-called hybrid beds, which include both an innerspring and high-end foams such as visco-elastic or latex in the comfort layers. In Europe, polyurethane foam cores and latex cores have long been popular and make up a much larger proportion of the mattresses sold.
A conventional mattress consists of two primary sections, a core or "support layer" and the upholstery or "comfort layer," wrapped in a thick fabric called the ticking. The upholstery layer consists of three parts: the insulator, the middle upholstery, and the quilt.
Innerspring mattresses commonly consist of just the spring core, and the top and bottom upholstery layers. The gauge of the coils is another factor which determines firmness and support. Coils are measured in quarter increments. The lower the number, the thicker the spring. In general, higher-quality mattress coils have a 14-gauge (1.63 mm) diameter. Coils of 14 to 15.5-gauge (1.63 to 1.37 mm) give more easily under pressure, while a 12.5-gauge (1.94 mm) coil, the thickest typically available, feels quite firm. Most coils are connected by interconnecting wires; encased coils are not connected, but the fabric encasement helps preserve the mattress shape.
There are four types of mattress coils:
Bonnell coils are the oldest and most common. First adapted from buggy seat springs of the 19th century, they are still prevalent in mid-priced mattresses. Bonnell springs are a knotted, round-top, hourglass-shaped steel wire coil. When laced together with cross wires, these coils form the simplest innerspring unit.
Offset coils are an hourglass type coil on which portions of the top and bottom convolutions have been flattened. These flat segments of wire are hinged together with wires. The hinging effect is designed to conform to body shape.
Continuous coils are an innerspring configuration in which the rows of coils are formed from a single piece of wire. They work in a hinging effect similar to that of offset coils.
Marshall coils, also known as wrapped or encased coils or pocket springs, are thin-gauge, barrel-shaped, knotless coils individually encased in fabric pockets—normally a fabric from man-made, non-woven fiber. As the springs are not wired together, they work more or less independently: the weight on one spring does not affect its neighbors. More than half the consumers who participated in a survey had chosen to buy pocket spring mattresses.
The insulator separates the mattress core from the middle upholstery. It is usually made of fiber or mesh and is intended to keep the middle upholstery in place.
The middle upholstery comprises all the material between the insulator and the quilt. It is usually made from materials which are intended to provide comfort to the sleeper, including flexible polyurethane foam, latex foam, felt, polyester fiber, cotton fiber, wool fiber and nonwoven fiber pads. In Europe and North America, mattress makers have begun incorporating gel-infused foams, soft-solid gels layered over foam, and poured gels in the top comfort layer of the bed.
The quilt is the top layer of the mattress. Made of light foam or fibrers stitched to the underside of the ticking, it provides a soft surface texture to the mattress and can be found in varying degrees of firmness.
There are three main types of foundation:
A traditional box spring consists of a rigid frame containing extra heavy duty springs. This foundation is often paired with an innerspring mattress.
An all-wood foundation usually has seven or eight support slats disposed below paperboard or beaverboard. All-wood foundations have become increasingly prevalent as U.S. mattress makers shifted to super-thick, one-sided mattresses.
A grid-top foundation is a combination of steel and wood.
Ticking is the protective fabric cover used to encase mattresses and foundations. Mattress fabrics can be knits, damask or printed wovens, or inexpensive non-wovens. Most ticking is made with polyester yarns. More expensive mattress fabrics may contain a combination of polyester with rayon, cotton, silk, wool or other natural yarns.
Foam mattress use different weights and densities of petrochemical-based flexible polyurethane foams or memory foam, and latex rubber foams. Memory foam mattresses offer different feels and comfort levels by varying the thickness, weight and formulation of the foams.
Memory foam is affected by temperature. In a cool bedroom, a memory foam mattress will feel firmer than it does in a warm bedroom. Memory softens and conforms to the sleeper in response to body temperature and body weight. Traditional memory foam molds to the body creating a depression the sleeper must roll out of when changing sleep positions. Mattress manufacturers have responded to this issue by using "faster response" memory foams. They spring back more quickly when the sleeper moves. Foam mattresses are also known to generally "sleep warmer" than innerspring mattresses. Mattress makers have addressed the issue with "open-cell" memory foams, pinhole cored memory foam, gel-infused memory foams, channel-cut foam cores, reticulated foam support layers and other technologies to improve air circulation through all-foam beds.
Similar to memory foam mattresses, a high density foam mattress uses a more compact foam typically made from polyurethane. High density foam mattresses offer comfort and longevity because they are more dense than a traditional foam mattress.
The U.S. Consumer Product Safety Commission advises consumers not to let infants sleep on air mattresses. This is motivated by reports of deaths, mostly infants younger than 8 months of age, who were placed to sleep on air mattresses, and either suffocated in a face down position on an air mattress or died due to suffocation after falling into gaps between the mattress and bed frame, or the mattress and adjacent furniture or wall.
Mattresses deteriorate over time, and the lifespan of a mattress depends on a variety of factors, notably materials, manufacturing quality, care, and how vigorously it is used.
A poor quality foam comfort layer can deteriorate in one year, while a quality latex core can last 20 years or more. Innerspring cores typically last around 10 years.
The comfort layer is almost invariably the first area to fail, which is why mattresses are often double-sided, to extend the lifespan. In the United States, mattress warranties are typically for 10 years or 20 years, sometimes 25 years, though this specifically addresses manufacturing defects and faster-than-normal deterioration, not expected deterioration with time. In the United States, as of 2008 there is a general expectation that mattresses should last about 10 years, and this is the average number of years Americans keep mattresses, though this varies by age group. This expectation is based on a number of factors, including: sales pitches; the expectation that mattresses will last the length of their warranty, hence 10 years or 20 years, accordingly; and comparison with other household items. The mattress industry has a financial incentive to shorten the replacement cycle which on current television ads is eight years. International Sleep Products Association (ISPA) established the Better Sleep Council (BSC) in 1979 with the stated goal to shorten the mattress replacement cycle and to encourage people to invest in better bedding.
The main wear problems that can occur with a mattress are sagging, mildew, and staining. These are prevented by proper support, rotation and flipping, keeping it dry, and using a mattress pad or protector.
Mattresses require a solid foundation which does not itself sag. Consistently sleeping in the same place and body position causes excessive wear, and thus rotating or flipping mattresses is used to reduce this. Flipping or rotation schedules are typically recommended monthly for the first six months and every two or three months thereafter. Foundations should also be rotated, if possible, though less frequently – rotating box springs twice a year is recommended.
Mattresses require ventilation to remain dry and prevent mildew and should not be placed directly on the floor or on a solid surface. Additional ventilation is recommended for natural materials, in which case leaving the mattress naked after stripping sheets is recommended. If a mattress gets damp is mildew may develop inside the upholstery; cleaning with a vacuum cleaner or mild surface cleanser and a slightly damp cloth is recommended.
Mattresses absorb fluids and stains readily, notably from sweating (result...a yellow stain) and other bodily fluids. These visibly stain the ticking, and seep through into lower layers. You shed millions of skin cells per day, and since you spend about one third of each day sleeping a significant portion of them end up in the bed. You also sweat while sleeping, anywhere from a several milliliters to one liter nightly. In addition to being unhygienic, hard to launder, and unsightly, such stains typically void a warranty. Thus a mattress protector is recommended.
In the U.S. mattresses are mostly the same and are often sold under different brand names. Serta and Simmons, for example, are owned by the same company. In 2012, Sealy Corporation was purchased by Tempur-Pedic.
Innerspring mattresses are sold the most, accounting for an estimated 80% of mattress sales. But, they also have the lowest overall satisfaction ratings. Only 63 percent of innerspring mattress owners report being satisfied, compared to around 80 percent of memory foam and latex owners.
Mattresses can conceal thousands of microscopic dust mites and their excrement. Dust mites exist just about anywhere there are fabrics and carpet plus animals or people, especially in more humid environments. They feed on shed skin cells, and while they don’t bite or pose disease risks, they can exacerbate allergies and asthma. Pillows are another favorite hangout for dust mites (and skin oils and saliva) so replace your pillow at least every year and a half.
The best way to minimize dust mites is to use allergen-resistant mattress and pillow covers and wash all bedding in hot water once a week.
Recycling mattresses is growing industry and many states and organizations are pushing the development of mattress recycling to reduce waste. California, Rhode Island and Connecticut have all passed laws that will now require mattress recycling. Springs and metal, wood, fibers and foams can be recycled.
One of the number one places that home robbers look for hidden money and other possessions is under the mattress.
A Kingston University study found that an unmade bed might be a little healthier. The idea is that when you make your bed and cover the mattress with the comforter, sweat and moisture is trapped within creating the ideal environment for dust mites. Leaving sheets exposed to the air and sunlight dries out the environment which can help kill of mites.
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