Mattress

A mattress is a mat or pad, usually placed on top of a bed, upon which to sleep or lie. hough a mattress may be placed directly on the floor, it is usually placed on top of a platform (such as a platform bed or a metal box spring or a slatted foundation) to be further from the ground. Historically, mattresses have been filled with a variety of natural materials, including straw and feathers. Modern mattresses usually contain either an inner spring core or materials such as latex, viscoelastic, or other polyurethane-type foams. Mattresses may also be filled with air or water, or a variety of natural fibres, such as in futons.

Bonnell coils are the oldest and most common. First adapted from buggy seat springs of the 19th century, they are still prevalent in less expensive mattresses. Bonnell coils are hourglass-shaped, and the ends of the wire are knotted or wrapped around the top and bottom circular portion of the coil and self-tied. Marshall coils are each wrapped in a fabric encasement and usually are tempered, or in the case of Beautyrest Simmons Bedding Company high carbon magnesium is added while the steel itself remains untempered." Some manufacturers pre-compress these coils, which makes the mattress firmer and allows for motion separation between the sides of the bed.

Air mattresses use one or more air chambers instead of springs to provide support. Quality and price can range from inexpensive ones used occasionally for camping, all the way up to high-end luxury beds. Air mattresses designed for typical bedroom use cost about the same as inner-spring mattresses with comparable features. Several companies currently produce adjustable firmness air mattresses. In 1981, Comfortaire began manufacturing and marketing air mattresses that looked conventional but allowed users to adjust the firmness. Select Comfort patented a variant and began marketing them in 1987.

Foam mattresses use shape-conforming latex or viscoelastic memory foam rather than springs to provide support. Mattresses manufactured using memory foam or latex are generally hypoallergenic. Since foam varies in quality, prices can vary widely. Most mattress manufacturers offer a line of memory foam mattresses. A quality innerspring mattress should last between 10 and 15 years before it needs to be replaced. Memory foam and latex models should last between 15 and 20 years depending on the manufacturer and the quality of the bedding. This is an approximation, as many factors affect the lifespan of a mattress.