The modern mattress is a relatively new invention bringing comfort and rest to humanity who, until 200 years ago had to accept pests and bugs as companions to their nightly sleep. Until that time mattresses were stuffed with hay, straw, wool, sawdust or other organic materials. Once cotton stuffing and cast iron frames were introduced, bugs became less common, and later in the century the first coil spring mattresses were invented.
Before that the springs were stretched on the frame and the mattress was laid on top of this, but the innerspring design moved the springs to within the mattress itself which then sat on a rigid base. In more recent times this design has been reworked with new materials including foam and air bladders. Of course bedding technology in other parts of the world also continued to evolve, including the futon, materials such as bamboo, water beds, and specialty beds such as fold-out sofa beds or Murphy beds, temporary air mattresses and medical beds.
The Innerspring Mattress
A modern innerspring mattress is an array of wire springs set in a wire framework and wrapped in a covering, often with an extra cushion on the top. Selling features for these mattresses focus primarily on the number of coils in the mattress. The claim is that the more coils there are, the more comfortable the mattress is, but many mattress testing and reviewing agencies insist that there is an upper limit to this. After about 400 coils there is little noticeable difference to comfort.
The springs coils themselves are a technology that has been evolving over time as well and this is probably more important than coil count as far as comfort is concerned. There are several factors to consider with coils like the thickness (gauge) of the wire used to make them and the style of construction. Thicker wire, meaning a lower gauge number, means a firmer spring and a firmer overall mattress than thinner wire.
The completed coils can also be tempered to increase their durability. Tempering is a common metallurgical technique where the metal is repeatedly heated and cooled to help the metal hold the shape. The construction of the coils comes in three general flavors: pocketed, hourglass and continuous.
Different Kinds Of Coils
The least expensive coil construction is the hourglass coil, making it the most common. Hourglass comes in two variations called Bonelli and offset. Bonelli coils are narrower in the middle and are the oldest spring design. This was later modified into the offset coil which has a hinged action and is not narrower in the middle like the hourglass.
It is open ended, meaning the wire is not twisted back around itself. Next in terms of history and expense is the continuous spring which takes the coil, turns it on its side and runs it the full length of the mattress from top to bottom. This spring is sometimes called a Mira-coil and has a hinged action like offset coils.
When looked at in cross section the spring looks like an S-shape and it is difficult to compare these continuous springs to individual coils directly, though the industry uses an equation to equate the two. The continuous spring system may be more durable than other types, leading to longer mattress life, but it is common for continuous coils to be more noisy than other types. Finally there is the pocket coil spring, which is an individual coil wrapped in a cotton bag.
The coil itself is not hourglass shaped but rather is a straight-walled shape making it a softer spring compared to an equivalent hourglass coil. The pocket coil is also called the Marshall coil after its inventor, and is the most expensive of the three spring types. The claim is that pocket coils are more independent than the other types of spring, less likely to transfer motion from one part of the bed to another.
Pocket coils also require the least amount of padding in the top layer. Some mattresses increase the coil count or stiffness around the edges of the mattress to increase firmness and reduce wear caused by sitting on the edge of the bed. Coil mattresses require a top covering to mask the rigid wire construction beneath and the thickness and material of this covering is how various brands and models distinguish themselves and help salespeople to relieve you of your money.
Solid Foam Mattresses
Perhaps the most important development in recent years is the development of solid foam mattresses. Since the 1950’s, safe foams such as polyurethane memory foam and latex foam are among the most highly rated mattresses for customer comfort and eliminating the sensation of movement from one part of the mattress to another.
Manufacturers of foam mattresses have different construction methods including layering the foam in different densities or adding a gel to the foam to help cool the body, but the main quality of these mattresses is that it softens and adjusts to your weight over time. The foam then returns to its original shape when not in use, or when you move.
This behavior means the foam is in close contact with the body, leading some to complain that they get hot while they sleep. Another complaint of memory foam is that it off-gases and produces a polyurethane smell that is unpleasant. Latex foam is an option to polyurethane and may eliminate the smell of off-gassing and may be more hypoallergenic. As with any product that off-gasses, a memory foam mattress can be left to air out to reduce the problem.
Gel layers are added to produce a cooling effect to offset the warmth of memory foam, but tests show that this feature is largely useless, especially since the gel is covered by additional layers. The popularity of foam is leveraged by coil mattresses that add a layer of foam on top of the coil, but this also is not effective other than as a marketing gimmick because they are too thin to influence the underlying coil action beneath. Foam mattresses may have a quilted top but this is not strictly necessary.
The 1980’s saw the introduction of the air bed which has evolved into the modern adjustable air mattress. Anyone who has used a temporary inflatable mattress knows that they are not a serious permanent solution as they transfer motion to all parts of the bed like a water bed does, and unless you add blankets to the surface they can wick the heat away from your body and leave you cold and stiff in the morning.
While adjustable air mattresses use air pockets to provide support, they are not to be confused with inflatable guest mattresses. They contain multiple air bladders that isolate movement and come with an electric pump that is used to adjust the firmness.
Air mattresses have a foam or quilted layer to provide the comfort expected from a traditional mattress and in fact look no different from other types of mattresses. Adjustable air mattresses are unique in that they are one of the only mattress types that allow the two sides of the bed to have different firmness settings for partners with different needs. One thing to watch with air mattresses is to maintain the inflation pressure, otherwise the bed can become very soft and cause pain on waking.
What To Look For
When shopping for a mattress you must balance your budget, mattress life, and any special needs that you may have. Although the impulse of frugality dictates that you look for a mattress that will last the longest compared to others, this logic breaks down for at least a couple of reasons. First of all the premium mattresses that will last the longest are also the most expensive initial investment.
Secondly there are good reasons to plan to keep a mattress for only a limited time. For one thing, your body will change over time, as will other factors such as the coming and going of sleeping partners who have their own needs.
You may move to a new home or apartment and need to change the size of your bed. Mattresses accumulate dirt, wear, stains, smells and host a variety of biological life including dust mites. A major factor to consider when balancing the short and long term investment of a mattress is whether the mattress is one or two sided. This is referred to as flip versus no-flip.
The traditional way to extend the life of an innerspring mattress was to rotate and flip the mattress periodically, allowing the most-used parts of the mattress to recover and generally spreading wear out evenly (think of it as doing regular tire rotation on your car). No-flip mattresses have come to dominate the market and feature a top layer on only one side of the mattress. Other features, largely found to be useless, such as having different firmness zones from top to bottom for lumbar support also make the rotating of mattresses theoretically impossible.
A savvy consumer should instantly recognize this as planned obsolescence and might want to seriously consider buying a cheaper innerspring mattress that is intended to be regularly flipped and rotated if long mattress life at low initial cost is a priority. Separate mattress toppers can be purchased and can be added to even a very minimal innerspring mattress, and can be kept when the mattress is replaced. Toppers can be of the air mattress type which brings some of the benefits of air mattresses to even an inexpensive innerspring mattress.
Foam mattresses are less prone to wear from body impressions and unless they have an elaborate top layer can be flipped and rotated as well. In general spending more on an innerspring mattress will not make much difference to your comfort.
Special requirements may force you to invest in a more costly mattress that employs some of the more advanced construction technologies covered so far. Foam and adjustable air mattresses are going to be the best option for couples who have different sleep needs or behaviors. People who suffer from lower back pain have reviewed firmer mattresses more positively than softer ones. Most people even without back problems rate beds of median firmness as being best.
Memory foam mattresses reduce pain and adjust to pressure points better than other types and are best for people who suffer from muscle pain, joint or back pain, or conditions like chronic fatigue. If you need a firm mattress consider a latex foam mattress.
People who are overweight may benefit best from an innerspring mattress which offers the best support for heavy bodies and makes getting in and out of bed easier. Mattresses for adjustable beds such as medical beds require mattresses that are flexible and can withstand the wear of changing shape and folding. Mattresses in campers, RVs and boats are predominantly foam, as are mattresses made for folding sofa beds.
It is difficult to shop around for a mattress. Retailers carry limited makes of each mattress and many manufacturers construct their various models differently for different regions making it difficult to compare them. When going mattress shopping bring a pillow and dress comfortably and plan to spend about 15 minutes resting on the mattresses you are seriously considering. Remember that mattress sales is a competitive and often commission driven industry.
Avoid being talked into a more expensive model in the same line that offers more features that you may never even notice. Check the internet for mattress reviews and consumer reports and consider buying a mattress on-line.
Mattresses are no longer the specialty of department stores and you can buy foam directly from foam retailers or even wholesalers cut exactly to your requirements. A big selling point for mattresses is the warranty and the trial period it comes with. Some manufacturers offer up to 100 days of grace during which you can return the mattress if you are not satisfied.
If the warranty does not require you to buy the matching box-spring then consider using your old box spring to save up to several hundred dollars. Delivery may be included or added at a cost and when your mattress arrives inspect it for signs of having been used previously or having been damaged during shipping, and check to see that the mattress label is intact.