Innerspring Mattresses

The most popular mattress type

Innerspring mattresses are the most popular and familiar type. They are cheaper than other mattresses, and experts at WebMD.com say they are comfortable for most people. However, a dizzying variety of brands, models and features can make shopping for an innerspring mattress confusing. Sealy, Simmons and Serta rule the market, but there are dozens of other brands out there, including Spring Air, Kingsdown and Stearns & Foster (owned by Sealy). Each manufacturer offers a variety of lines, from basic, unadorned beds costing just a few hundred dollars to fancy pillow-top mattresses with hand-stitched embroidery, which can run into the thousands. To make matters worse, manufacturers have dozens of names for models that may vary only slightly in features, allowing each store to sell a specific model as an "exclusive." The result is that it's impossible to comparison-shop based on the model name.

All innerspring mattresses share the same basic structure: one or more layers of coils, topped by padding, quilting (the top layer of padding) and ticking (the outer cover of the mattress). Differences between less expensive models and more expensive innersprings include qualities you can see, such as pillow tops (an extra layer of cushioning on top of the mattress), mattress height and ticking fabric. But it is the details that don't show -- such as coil gauge, coil count and upholstery materials -- that determine firmness, durability and overall comfort. Most mattress stores display cross sections of mattresses so you can see their interior components, but what should you be looking for when you analyze a mattress's construction?

The core of any innerspring mattresses is the springs, which give support and make the mattress firm or soft. Springs come in four basic shapes:

• Hourglass-shaped springs, which are joined by spiral wires, compress easily when new. But as the springs compress over time, the mattress becomes firmer. Mattresses made with hourglass springs are cheaper than other types. Budget mattresses like the Sealy traditional innerspring (*Est. $400 and up for a queen size set with box spring) use hourglass springs.

• Continuous-coil springing is an arrangement of coils formed from a single length of wire. This allows manufacturers to increase the density of the coils, providing more support. However, because the springs move as a single unit, they transmit motion easily between two people sleeping in the same bed. Continuous-coil springs also tend to wear out more quickly than pocket springs. Serta's Perfect Sleeper series (*Est. $1,800, queen size) uses continuous coils.

• Open-coil springs are joined together by wire close to the middle of the spring, rather than at the top and bottom. This means that the end of each looped spring can compress independently, adjusting to the weight on top of it. Open-coil mattresses contain more wire than continuous-coil mattresses, and therefore cost more. Most Sealy Posturepedic mattresses (*Est. $600 and up for a queen-size set, with box spring) use open-coil springs.

• Pocket springs are the most expensive type. Each individual coil is sewn into its own fabric pocket and can react individually to pressure, without affecting the springs around it. Because the springs move independently, they transmit motion less, making this mattress type a good choice for couples. They can also be a good choice for side sleepers, as this position puts different amounts of pressure on different parts of the spine. Simmons' Beautyrest Classic (*Est. $1,420, queen size) mattresses use pocket springs, and Sealy announced in January 2011 that it would adopt the technology in a new line of Posturepedic mattresses.

Springs don't just differ in shape; they also differ in strength, or wire gauge. A lower gauge translates to thicker wires, which in turn make a stiffer mattress. Higher gauges mean thinner wires, which provide a springier mattress. Heavy-gauge coils are more durable than light ones, and they provide more support. However, a mattress with a smaller number of lower-gauge springs will become lumpy faster than one with more and lighter springs. Spring distribution throughout the mattress may also vary. Some manufacturers put firmer springs in the central part of the bed, since that is where the body needs the most support. Others add firmer springs along the edges of the mattress for the times when you sit on the edge of the bed. Stearns & Foster innerspring beds (*Est. $1,300 and up for a queen set) are known for good edge support.

Mattresses can have as many as 700 individual coils, but you don't need such a high coil count to get a quality mattress. Editors at Choice magazine say a good mattress should have a minimum of 300 coils in a full-size bed, 375 in a queen size and 450 in a king size. Beyond that, they claim, more coils aren't necessarily better. Editors at WhatsTheBest-Mattress.com say that in general, a mattress with a higher coil count will provide more support, but they add that some people find a less supportive mattress more comfortable.

Other components of innerspring mattresses

Coils: The coils determine how much support your mattress gives you as you sleep, but the upholstery has the biggest impact on how comfortable it feels while you are awake. Some manufacturers use the same spring system in all of their mattresses, but use a variety of filling materials, which can significantly affect comfort, durability and price. Cheaper mattresses might use materials such as lower-grade foam, coconut fibers or reclaimed cotton, which can break apart or form lumps and pockets, losing the ability to spring back. Deluxe mattresses might include layers of wool, cashmere, latex, goose down or memory foam. Luxury layers such as these add significantly to the price. Higher-priced mattresses will typically hold up better, but a mattress that costs twice as much won't necessarily last twice as long. The extra cost is for extra comfort rather than increased longevity.

Padding: A mattress has several layers of padding. Insulation padding lies directly on top of the springs, preventing you from feeling them. Most innerspring mattresses use man-made foam for padding, but some use natural materials such as horsehair or wool. The editors of Which? magazine stress that more layers of padding aren't necessarily better; the support provided by the springs is more important. However, the editors of Choice magazine note that the way the padding is assembled can make a difference. Top-of-the-line mattresses stitch each individual layer of padding in place by hand -- a process called hand-tufting -- to prevent the layers from shifting around.

On top of the insulation padding you'll find a layer of padding, or quilting, usually made of polyurethane foam. This layer may also include polyester batting, which helps wick away perspiration and makes the mattress feel softer. The editors of ConsumerReports.org also note that egg crate foam, which has a dimpled pattern, feels softer than flat foam. Traditional mattresses had the same quilting on both sides, so either side could serve as the sleep surface. This made it possible to prolong the mattress's life by regularly flipping and rotating it. Today, many mattresses have only one sleep surface, so they can't be flipped, although they can still be rotated.

Some mattresses also include a pillow top, a cushy upper layer that adds extra plushness. Dr. Alan Hilibrand, MD, professor of orthopaedic surgery at Jefferson Medical College in Philadelphia and a spokesman for the American Academy of Orthopaedic Surgeons, likes pillow tops because they make it possible to tolerate a firmer mattress. However, pillow-top mattresses are expensive, and several consumer sites caution that they may not be worth the extra cost. We read in three separate sources (Choice magazine, ABC News and WhatsTheBest-Mattress.com) that pillow tops tend to sag or form craters over time, which may force you to replace your mattress even though the springs are still in good shape. If you want extra padding, the editors of Choice magazine recommend buying a separate mattress topper, which can be replaced as needed.

Ticking: The outermost fabric covering of the mattress is called the ticking. Materials used in the ticking vary from basic cotton or polyester to jersey knits, wool, silk or even cashmere. The editors of Choice magazine point out that damask ticking, which has fancy patterns woven into the fabric, isn't worth the extra cost, since it will just be covered up with a sheet anyway. However, the editors of ConsumerReports.org say that while the material isn't that important, the stitching that binds the ticking to the top padding can be. A larger quilt pattern will make the mattress feel more cushioned, while a smaller pattern will feel firmer.

What about the box spring?

The final factor to consider when buying an innerspring mattress is the humble box spring. The name is somewhat misleading, since most box springs do not contain actual springs. A typical box spring is just a wooden frame containing stiff wire, covered in fabric to coordinate with the mattress. Box springs aren't actually springy; they simply support the mattress. However, although a box spring is much simpler than a mattress, it can often cost just as much. The editors of ConsumerReports.org note that manufacturers often pair mattresses in different price ranges with the same box spring, so you may be able to save on a set by buying a lower-priced foundation with a high-end mattress.

Experts disagree on whether you should always replace the box spring along with the mattress. The editors of WhatsTheBest-Mattress.com insist that the two should always be bought as a set. They admit that a new mattress will feel the same on an old box spring as it does on a new one, but they claim that using the old box spring will reduce the life of the mattress by more than half. "Most brand name mattresses these days will last 10 years on a new box spring," they say, "while a mattress on an old box spring will only last 3 to 4 years." However, the editors of ConsumerReports.org disagree, saying, "As long as it's in good shape -- no cracks, rips, warps, or dips -- the old foundation ought to provide adequate mattress support and perform as it's supposed to." The editors of Which? magazine take a middle position, saying that it's wise to buy the mattress and base as a set "if you've had your old base for many years."

Another problem with keeping your old box spring is that some manufacturers insist that the mattress and box spring be purchased as a set. Pairing a new mattress with an old foundation could void your warranty. Before buying a mattress, it's wise to check with the stores or the manufacturer to find out whether you must also buy a box spring to maintain the warranty. If you do choose to keep your old box spring, it's important to measure it to make sure it's the right size to support the new mattress.

If you don't need to purchase a box spring to maintain the warranty, you may want to consider a slatted bed base instead. A slatted base has advantages and disadvantages. The mattress may last longer on a box spring, which can take some of the load off the mattress; however, a slatted base can easily last a lifetime, while a box spring will wear out much sooner. Some bed bases have slats that are simply fixed to the frame, while others have flexible slats attached by pivots. Fixed slats work fine for innerspring mattresses, but flexible slats are preferable for foam mattresses (discussed in the next section). Ideally, slats should be no more than about 2.4 inches wide and 1.6 inches apart. This will ensure sufficient ventilation without allowing the mattress to sag.