By Wesley Vaughn
When adjustable beds became available for home use, they were commonly called “hospital beds.” This was only natural, since until that time adjustable beds were primarily used in hospitals.
The first adjustable beds were beds with adjustable side rails, first used in English hospitals in the early 1800s. Then beds could be tilted with either the foot high (Trendelenburg position) or the head high (anti-Trendelenburg). In 1874 the first articulated bed was patented by Andrew Wurst & Son, a Cincinnati mattress manufacturer. This bed was hinged in the middle so the head could be raised. Then the 3-part hospital bed was developed at the Indiana University School of Medicine in the early 1900s.
Up to this time, all beds were adjusted manually. At first, the elevated part was lifted by hand and fixed in place. Later, they were adjusted with cranks and gears. Then motors were added for lifting and lowering the bed and tilting its sections. In 1945 a motorized hospital bed with push-button controls was patented.
Care of patients was the original reason for adjustable beds. Side rails were for safety, as well as an aid for a patient trying to sit up. The Trendelenburg position was for abdominal surgery. Raising the head and torso to a sitting position eased stress on the abdomen. More available positions meant better positions for the patient’s health and comfort. And raising or lowering the bed as a whole made caring for patients easier.
The first adjustable beds sold for home use were hospital beds, intended for home care of patients. For some people, this was the only way they could be at home. My grandfather spent the last couple of years of his life at home in a hospital bed after suffering massive strokes.
In 1974, 100 years after the invention of the articulated bed, Craftmatic began selling adjustable beds designed specifically for home use. These were not hospital beds, but were designed to be used for one’s health. Customers bought them not only for their backs and necks and for better breathing, but also for comfort. My parents had a Craftmatic bed.
Following this, a number of manufacturers began making and marketing adjustable beds for the home. Some were already producing hospital beds. Some started with the home market. Now there are at least a dozen manufacturers of home use adjustable beds. Among the leading producers are Craftmatic, Leggett & Platt, Reverie, and Ergomotion.
Beyond health and comfort, manufacturers and retailers are now marketing adjustable beds for convenience and lifestyle. Even the term is often changed to adjustable “base” or “foundation.” They can be used for more than sleeping or therapy. “Your bedroom is now your den,” they say. “The positions of the bed make it suitable for reading, watching TV, writing, working on your laptop or tablet, or just visiting.” The sides of many adjustable bases have pockets for various items, outlets for your devices, USB ports, under-the-bed night lights, etc. And style—today’s adjustable foundations are upholstered to match the mattress and/or coördinate with the room décor.
As the market for adjustable beds/bases/foundations has increased, so has the number of features. Many models now have massage functions, operating in pulses, waves or combinations. Some have heaters. Remote control handsets were wired at first. Some still are, but now most are wireless, many programmable. The newest remotes are digital, even wi-fi and Bluetooth capable, controlling room functions such as lights and fans. With available apps, users can control their adjustables from their smart phones or tablets.
The bottom line is that adjustable beds are still beds. That is their primary function, however they are otherwise used or marketed. So when you consider buying an adjustable foundation for your new mattress (or a complete adjustable bed), first look at how it functions as a bed. Will the positions help me sleep? Would this really help with my back? My asthma? My acid reflux? What are the safety features? And, of course, the multi-thousand-dollar question: Is this worth the cost? If with these features you will really be adjusting for health and comfort, and you can afford the price, it may be.
Select Adjustable Bed Manufacturers
(Ones reviewed on Beds colored blue)
Flex-A-Bed – http://www.flexabed.com/
Med-Lift – http://www.medlift.com/
Reverie (Ascion) – http://www.reverie.com/
Leggett and Platt – http://www.lpadjustablebeds.com/
Mantua (Rize) – http://bedframes.com/rize
Ergomotion – http://www.ergomotion.com/
Craftmatic – http://www.craftmatic.com/
Tempur-Ergo [designed by Tempur-Pedic] – http://www.tempurpedic.com/tempur-ergo-adjustable-bases/tempur-ergo-adjustable-bases.asp
Electropedic – http://www.electropedicbeds.com/
Customatic – http://www.customaticbeds.com/
Christeli - http://www.christeli.com/adjustable-beds
Sleep Science - http://www.southbayinternational.com/index.php
By Wesley Vaughn
Ever since the transition from woven sleeping mats, mattresses have been covered. Whether filled with sawdust, straw, or feathers, a cover—also called ticking—defined the shapes and dimensions of the earliest mattresses. The role of the cover was to hold the loose materials in place.
The first cover materials were whatever was available where the mattresses were made, whether linen, wool, cotton, or some other fiber. The first requirement was durability. The fabric had to be strong enough to hold the fill under the sleeper without rupturing, spilling the contents and losing its support. The grain of the fabric had to be close enough to keep the cushioning materials from leaking through. With small caliber loose fill material, a tight weave was preferred over knit. With the invention of innerspring mattresses, the cover held padding against the springs to cushion sleepers against the ends of the coils.
In the United States, mattresses were first made locally. Thanks to the U.S. cotton industry, the almost universal mattress cover material was heavy cotton canvas. Some luxury mattresses were covered with linen. Early commercial cushioning materials were cotton or wool batting and horsehair. Then, toward the end of the 19th Century, wagon seat springs were modified for the first innerspring mattresses as Bonnell coils, and padding served as cushioning over the springs. Mattresses still needed covers, and sturdy cotton continued to be the expected material.
When synthetic fibers became more widely used in clothing, they also began to be used in covering mattresses, usually polyester in a blend with cotton. Polyester increased durability, reduced shrinkage, and lowered the cost.
Mattress cover fabrics were generally woven, though the contents were no longer loose materials. But with the introduction of memory foam mattresses by Tempur-Pedic with memory foam’s conformability, knit fabrics were preferred because they could stretch with the surface of the foam. Several fabric forms are available now: damask, jacquard, terry, velour, microsuede, flocked, and others.
Beginning with manufacturers of luxury mattresses, such as ES Kluft and Aireloom, silk and cashmere joined linen as luxury mattress cover fabrics. Then the quest for healthier and environmentally responsible materials led to new mattress coverings, such as bamboo, wool. Wool is advertised as coming from several sources. OMI stresses its use of domestic wool, while others cite wool from France, New Zealand or some other country. For some of its models, Carolina Mattress Guild uses Repreve, fibers made from recycled plastics, such as beverage bottles.
Rayon is used in covers, too, not only as the cover fabric, but more often as the fire barrier just below the fabric. Since rayon naturally impedes the spread of flames, mattresses can meet federal flammability standards without using chemicals. Several mattress makers are using organic materials as much as possible. These include organic cotton, grown without pesticides, and untreated wool. There are several blends of fibers in cover fabrics. The most used are polyester-cotton, silk & wool, and bamboo & cotton.
On early mattresses, the entire cover was of the same material. Now the sides are covered differently. And with one-sided mattresses, the bottom panel differs from the top panel.
Temperature control also produces new mattress coverings. The first applications are for breathability. The use of foams made mattresses warmer, sometimes too hot. The initial solution was airflow. When the cover is breathable, air flows through it better, carrying heat away. The Space Age produced Outlast, a material developed for use in space suits. Outlast uses phase change materials to absorb extra heat when too hot and releases heat when it is too cool. Now several mattress models by different manufacturers are covered around the border (the sides) with mesh to allow grater airflow for cooling.
Other fabric materials such as CoolMax are profiled to channel moisture away from the surface, keeping it both cool and dry. This brings about an irony. Horsehair was among the early mattress cushioning materials. Now Stearns & Foster uses Mongolian horsehair in the covers of its Golden Elegance mattresses for moisture wicking.
Fabrics are often treated to make them more healthful or aesthetically pleasing. Some of the treatments are aloe vera, lavender, gel, silver, and vitamins.
Mattress covers can be quilted or non-quilted, tufted or non-tufted. In quilted covers, the quilting materials share billing with the cover fabric. Quilting foams may be polyurethane, memory foam or latex. Sometimes these are gel-infused to enhance cooling. Quilting fibers are also used, such as polyester, Dacron, rayon, cotton, various kinds of wool, cashmere, etc. The functions of quilting materials can be cushioning, softness, warmth, coolness, and breathability. In SpringAir’s reintroduced Four Seasons line, the quilted topper is reversible. One side has a Joma wool quilted cover for warmth. The other is quilted with silk & fibers for cooling. Whatever the firmness level of a mattress, a quilted cover is perceived as luxurious, even though it is fairly common now.
There are several considerations used by mattress designers in selecting cover materials. Among these are comfort areas such as surface texture, conformity, breathability, and how warm the underlying material gets. Health issues include allergies, mold & mildew, pathogenic microbes, and pests (such as bedbugs). There are also the economic issues of durability and cost. Besides these are considerations of environmental impact, aesthetics, and class appeal. The goal of designing the cover of a mattress is to optimize the balance of these considerations for the best mattresses in the designated price range.
Sample list of cover materials by source
Plant origin –
Animal origin –
Treatments and other materials –
By Scott Braddam
Since about 2004, when I bought my current memory foam bed, I’ve been sold on the benefits of memory foam. There is truly no other feeling in the world which is close to sleeping on memory foam. Memory foam is like sleeping on silk sheets, unless you’ve done it, you can’t possibly understand why people rave about it. My bed is a pure foam bed, meaning no springs or framework of any kind, just layers of foam bonded together to create the mattress. I believe this is the best format, but memory foam on top of a spring base or adjustable air chamber can be good too. The bottom line is that if you have the option to use memory foam, I recommend that you do it.
I have had a lot of questions about memory foam over the years, first from friends and family and now from our readers, and the most common has to be about the most popular name brand. Tempur-Pedic was the first to introduce a memory foam bed in the United States, and has spent millions of dollars in research and development to refine their beds into the models available today. This is why they are the standard for memory foam beds, the benchmark by which all other companies are judged.
When I look at a mattress, I see so much more than just a name brand. With Tempur-Pedic, I see premium grade foams which excellent craftsmanship and durability. What I also see is room for improvement. One area for improvement is the cover used on most, if not all, of their beds. The cover is designed to be water resistant, which also means that it will not transfer air as well as a more breathable material. Basically, the cover material is woven onto a plastic sheet. This can create an overwhelming hot feel as you sleep. Tempur-Pedic does employ an airflow system which is actually two different ventilation areas in the base foam layers of the bed. This can help air circulation in the mattress itself.
Other mattress makers combat this in many ways. One way that I have seen which seems really attractive to me is the TempFlow. The TempFlow uses a breathable, non-water-resistant cover over a dual airflow system. Basically the top layers have a series of tiny holes which are vertical, and then the base foam is eggcrate which promotes horizontal airflow. This should increase the overall airflow in the mattress greatly.
Now, I do want to take a moment and let you know that I am not here to plug any mattress. I simply used these two brands to illustrate some concerns with memory foam beds. There are dozens of mattress manufacturers which use memory foam in their products. Which is the best?
Here are some things to think about if you plan to look at if you plan to shop for a memory foam bed.
Consider the foam density – Density is usually measured in the weight of the foam per cubic foot (in pounds). Tempur-Pedic uses a 5.3-lb density foam. Memory foam used in mattresses can be found in almost any increment from about 3-lb to 8-lb. The manufacturing process of the foam generally dictates that the heavier the foam is, the more expensive the mattress will be. A budget memory foam bed will have an average density of 3.5-lbs to 4-lbs. High quality memory foam mattress manufacturers will use the 5-lb to 8-lb memory foams more often, and the 8-lb foam is usually found on their top-of-the-line mattress models.
Consider the foam source – Memory foam is primarily produced overseas. Very few mattress manufacturers produce their own memory foam, but the number is growing. Tempur-Pedic makes their own foam. Some imported foams are very poor quality and suffer from irregularities, such as lumpy hard spots. These poor quality memory foams can vary in density from one area of the mattress to another. These mattresses may even state that the memory foam density is an “average” density. Foams made in the U.S.A. and the foams used by Tempur-Pedic are the best quality I have personally seen.
Consider the cover – Covers vary wildly. Look for cover options which give you breathability and durability. Exotic materials, like bamboo and silk may be the best, but good ole cotton and wool is a great place to start. Don’t be fooled by waterproof covers, they may add to the heat of the foam.
Consider the price – There’s an old adage which says “If something sounds too good to be true, it usually is”. A memory foam bed which boasts all of the features I have listed for $299 in a queen size is likely to be hiding something. The other side of the shopper adage above is, “You get what you pay for”. If you want to get a quality memory foam bed, make sure to plan on spending $700-$1,000 or more.
Consider the customer service – I preach on warranty and return period heavily. In my mind, if I am going to write a check with a comma, I need to know about what to do to get that money back if I am not satisfied. Sleep trial duration and qualifications, warranty coverage, terms, and requirements are all things that I will know well before I even consider the purchase. This ain’t no pack of gum here kids, you can’t just throw it away if you don’t like it.
Consider the usage – Ever seen a movie where the kid has an ultra tiny apartment and a huge TV or stereo? Well, I have seen it too many times in reference to a bed in a bedroom. Here’s a great rule of thumb for you – try to shop for the smallest size which will suit you, not the largest. Yes, a king bed will fit into a 10×10 room, but you will have less than 2 feet on either side and less than 4 feet at the end of the bed. This is not exactly what I would define as “practical”.
Originally posted in 2010 by Scott Braddam
What are innerspring coils made of? “Steel,” we say. Other options are: Stainless steel, titanium steel, titanium alloy, or some other metal alloy. That is it! Or it was—until now. Among the new mattress companies at the Winter Las Vegas Market in January 2014 is VitalWOOD USA, the U.S. distributor for VitalWOOD, a division of Hungarian manufacturer Bio-Textima.
This family-owned firm developed the wooden coil as an alternative to metal springs, releasing it in 2011. VitalWOOD touts their “metal-free mattress” as not contributing to electromagnetic pollution, because the wood does not resonate with electromagnetic radiation (otherwise known as radio waves). I remember the stories of old-style steel beds and springs acting as AM radio receivers, so there must be something to this claim.
Besides being free of electromagnetic pollution, VitalWOOD’s wooden springs are also made from a sustainable, renewable resource. There is also less environmental impact processing wood than in the making of steel (even recycled steel).
When I first read about springs made of wood, my question was, “How do they do that?” VitalWOOD has a video on their site showing how this is done. Knowing a little about woodworking, it did not surprise me. First of all, if someone doubts that wood can be a spring, point them to wood archery bows. Then in the mattress industry, European wood slat foundations work like box springs, because the carefully selected and crafted wooden slats are resilient. So the real question is, “How do they make the wood into coils?” Heat and moisture make the wood pliable enough to wind into coils. Watch the video, and see for yourself.
If selling mattresses and box springs with wooden coils is successful in the United States, especially if it cuts deeply into the mattress market, look for other manufacturers to develop their own alternative material coils. One or more domestic manufacturers will develop their own wood coil manufacturing process (or license it from VitalWOOD).
I have one more question: “What Will They Make Springs from Next?” If wooden innerspring coils prove a successful alternative to metal, expect other non-metal coils for mattresses to be developed. Already, spring coils for very light applications are being made of synthetic materials, such as nylon.
VitalWOOD – www.vitalwood.com
“This is how wooden-spring is made” – http://vitalwood.com/download/this-is-how-wooden-spring-is-made-vitalwood.avi
Bio-Textima – http://www.bio-textima.hu/en/
“Bio-Textima , the only mattresses in a metal-free design,” Sleep Tech Magazine, May 8, 2013 – http://www.sleeptechmagazine.com/bio-textima-the-only-mattresses-in-a-metal-free-design/
Perry, David, “Prana, Juel, SensorPedic lead Vegas newcomer list,” Furniture Today, Jan 24, 2014 – http://www.furnituretoday.com/blog/Bedding_Today/43878-Prana_Juel_SensorPedic_lead_Vegas_newcomer_list.php
“New Exhibitors At Specialty Sleep Association Las Vegas Market Showroom,” Furniture World, December 26, 2013 – http://new.furninfo.com/Furniture%20Industry%20News/2602
Microcoils (or minicoils) are coils which are smaller than standard innerspring coils. Innersprings are usually 6” to 8” high. Some microcoils are 4” high, but most are much shorter, usually 1” to 2½” high. They are also narrower and made with lighter gauge wire. Some microcoils are only ¾” tall. At least one supplier calls the shorter ones mini-microcoils.
Innersprings are designed for primary support, but microcoils are designed for comfort. The lighter wire gives them a softer feel, and more coils in a given area make them feel smoother.
Microcoils are the latest major development in mattress springs, but there is already a great deal of variety. Among their developers and manufacturers are major players such as Leggett & Platt, Hickory Springs Manufacturing and Spinks Springs.
Microcoils are sometimes called “micro-pocket coils,” because they are usually pocket coils, individual coils wrapped in fabric pockets, a design now often found in innersprings. Because each coil responds independently, a pocket coil layer conforms to body contours, helping to relieve pressure and dampen motion transfer. The pockets are sewn, glued or “welded” together. Welding at one point on a seam allows the coils to move sideways as well as up-and-down. Mattress makers call this “three-way stretch.” It makes the microcoil layer even more conforming.
Microcoils are sold to mattress manufacturers in sheets or layers covered top and bottom. The major advantage of microcoils is that since they are thinner than innersprings, they can be placed higher in the mattress, among the comfort layers. Several mattresses alternate layers of foam and microcoils.
One benefit of microcoils is that they are cooler than foam. They are open, allowing air to flow through, making them much cooler than memory foam. Some microcoil layers are covered with mesh to let even more air through.
Mattresses without coils are specialty sleep beds. Therapedic a manufacturer of specialty sleep products, now has a mattress collection with springs. Ágility models have microcoils and mini-microcoils, with heights of ¾, 1 ½ and 4 inches. The trend seem to be that more foam mattresses will also include microcoils.
Because of their flexibility and versatility, the use of microcoils in mattresses will grow. The advantages are durability, conformability and coolness. As microcoils and mini-microcoils are developed further, there will be a greater variety of design as well as sizes, yielding additional benefits. In this sense, smaller will be bigger.
Polyurethane (PU) foam is made by linking large molecules, usually isocyanates, to each other with modified oil molecules called polyols, usually petroleum-derived. Polyurethane foam is very durable and supportive.
Most of the issues with polyurethane foam are related to its manufacture. Isocyanates are toxic before becoming part of the PU foam. I used to work on a line making foam-filled panels for garage doors. Two liquids were injected between the sheet metal skins of the doors. They immediate blended and swelled into foam, which cured to become firm. One of the liquids was an isocyanate, and we had to be extremely cautious around it.
Another issue is outgassing. For some time after it is made, polyurethane releases gasses with an unpleasant odor. Careful selection of ingredients reduces the outgassing and the odor.
Many mattress manufacturers use “plant-based” polyurethane foam. From 15% to 20% of the polyols in this foam are from plant-derived oils. At the current level of technology. No more plant oils can be used and still have a high quality polyurethane. With further research & development, this may change. The plant-based polyols used are most often from soy oil, but other hydrocarbons, such as coconut oil and palm oil, are sometimes used. Further technological development may see the use of many other plant oils.
As stated above, memory foam was developed from polyurethane. It is denser than polyurethane. Visco-elastic foam also is more sensitive to heat. When someone sits or lies on it, the memory foam becomes softer, allowing the person to sink into it. This way it conforms to a sitter’s or sleeper’s body contours. The memory foam can be formulated to be more or less heat sensitive, therefore more or less conforming. With memory foam beds now widely available, manufacturers are competing to make the best memory foam mattress.
One drawback of memory foam is its heat build-up. When it absorbs heat, it becomes warmer. For a sleeper, this can become uncomfortable. Over time, several ways have been used to cool memory foam.
The first solution was to promote air flow to make memory foam breathable. Ventilating the foam by perforation or by cutting channels in its surface allowed air to flow through it and by it.
Then manufacturers began to make the cells in the foam open and more connected to make the foam itself permeable to air. Open-cell memory foam is more breathable than closed cell foam.
Now it is common practice to infuse the memory foam with gel. The gel acts as a heat sink, carrying heat away to where it can dissipate. The most common method of gel infusion is to stir beads of microencapsulated gel into the liquid used to make the memory foam. Variations of this are the size of the beads and the kind of gel. Another method used by a few manufacturers is to swirl liquid gel into the memory foam mixture. This memory foam has streaks of gel. Additionally, a layer of gel itself may be embedded in the layer of memory foam. Some models use this is for lumbar support.
Since memory foam is basically a kind of polyurethane, there may be some emissions. Using more plant-derived oils reduces this. However, memory foam has to be cut more slowly because of its “memory.” And it has to have time to recover before the next cut. This extra time allows the foam to air out more before being put into a mattress then packaged for shipping.
Formerly called “foam rubber,” latex foam is made in a number of ways. Foam rubber was first made by Dunlop, a tire manufacturer. Foaming agents were used to whipped liquid synthetic rubber into foam. Then rubber tree sap (natural latex) was whipped and cured into foam. Now there are several kinds of latex foam, depending on the proportion of natural latex and the composition of other ingredients. All natural latex foam is (or should be) made from 100% natural latex sap. Natural latex foam is partly synthetic. Then there is synthetic latex foam. Synthetic ingredients can be petroleum derived or natural ingredients, such as soy oil.
Latex foam is highly resilient. Its recovery time from pressure is virtually instantaneous. Latex is conformable, not as much as memory foam, but it is more durable. Its durability partly depends on the manufacturing process. Latex is used in some mattresses for the support core.
The oldest method is the Dunlop process. Liquid latex is mixed with the foaming agents and poured into molds to cure. The cured latex foam then is cut to specification.
Another common manufacturing method for latex foam is the Talalay process. The liquid latex is fed into a closed mold from which air has been removed. Freezing and insertion of carbon dioxide are used in expanding the foam, and heat is used to cure it. This is a more costly process, but it can be done without toxic ingredients or agents. Also, parts can be molded in their final form.
Like memory foam, latex is sometimes infused with gel for cooling. Latex foam is naturally breathable, and it is cooler than memory foam, but the addition of gel is seen as an added value for cooling and its smoother support. Latex is naturally resistant to bacteria, mold, mildew and dust mites. Properly washed latex foam is hypoallergenic, since allergens have been washed away.
Several mattresses on the market today use several kinds of foams, selected, sized and placed to optimize the use of their characteristics. Gel foams are usually at or near the top of the mattress where cooling is most needed. Firmer, more resilient foams are usually at or near the bottom to provide basic support. Layers in between tailor the comfort level of the mattress as a whole.
Most of us appreciate some cushioning when sitting or lying on a hard surface for very long. This has been true for thousands of years, with cushions for sitting and sleeping. Mattresses began with fiber sleeping mats laid out on a floor. At some point, long cushions or pillows were made, filled with wool, straw, feathers, sawdust, horsehair—anything to soften a hard surface.
In the middle of the 19th Century, coiled springs were invented for buggy and wagon seats. Later, these coiled springs were adapted for use in mattresses, what we call the Bonnell innerspring. For most of the 20th Century, the majority of mattresses were innerspring models.
The most durable innersprings are also very firm. Mattress manufacturers cushioned this with batting, usually cotton, sometimes wool or other fibers. But with the introduction of polyurethane and foam rubber, foam began to be used for seat cushions, then as cushioning on innerspring mattresses. Various configurations were introduced, including convoluted (or “egg crate”) foam.
With manned space flight, better padding was needed to cushion astronauts against high G forces at launch. NASA contractors modified polyurethane foam to produce visco-elastic foam. This was further developed by corporate firms for consumer use, becoming memory foam.
First used for seat cushions, memory foam began to be used in pillows, mattress toppers and mattress cushioning. Eventually, all-foam mattresses were introduced, with high-density polyurethane foam as the support core. These non-spring mattresses are collectively called “specialty sleep products.”
The three major kinds of foam uses in mattresses are polyurethane foam, visco-elastic memory foam, and latex foam. Each kind of foam has variations. First, there are different ingredients in these foams. Then there are different densities and firmness levels. Now gel is infused into different foams to add desired characteristics.
Foams for bedding are rated by density and Indentation Force Deflection (IFD). Density measures pounds per cubic foot. IFD measures how many pounds it takes to make a 1” indentation.
Part 2 will cover the different kinds of mattress foams
What kinds of springs are in your mattress?
The best selling mattresses over time have been innerspring mattresses. The first mattress springs were adapted from buggy seat springs. These springs are called Bonnell coils. For a long time, they were the only kind of springs used in mattresses. Now there are several types of innerspring coils. The major kinds are Bonnell, Offset, Continuous and Pocket. Within these kinds are variations. Each type of innerspring has its own advantages and disadvantages.
These are the oldest type of mattress innerspring coils. Adapted from buggy seat springs, they were patented by Louis Andrew Vargha in the 1800′s (1). They are shaped like an hourglass and tied together with small helical wires. Less expensive to make, they are usually found in inexpensive mattresses. They are initially very supportive, but are not very durable unless made of heavy-gauge tempered wire, especially when using special alloys. Therefore, they do not usually have a long lifetime.
One advantage which is also a disadvantage is the hourglass shape. This makes the Bonnell coil very flexible, but it a weak point which can give way and sag. This is why Bonnell coil mattresses usually have shorter warranty periods. Another disadvantage is that weight on one part of the innerspring pulls down a large area of the surface. When one sleeper moves, the other sleeper feels it. This is called “motion transfer.”
A Bonnell coil mattress may be a good low-price choice if it is well made with heavy-gauge coils, and the cost is small enough that you can replace it by the end of the warranty period.
Offset coils, sometimes called Karr coils, were developed from Bonnell coils. They were invented early in the 20th Century by Frank Karr, the founder of mattress manufacturer Spring Air.
The ends of the offset coil are not circular in shape like the Bonnell, but are squared-off on opposite sides. Each squared side of an offset coil is tied to that of another coil by a short helical wire. This connection is like a hinge, allowing the surface of the innerspring to be more flexible than the Bonnell. This means less motion transfer.
Often, offset coils are described as “alternating.” The coils alternate in the direction they turn; one turns to the right, the next to the left.
Offset coils are more durable than Bonnells. The hourglass shape is less pronounced, and the wider middle is stronger. Offset coils are more likely to be found in more expensive innerspring models, both because of the higher quality and durability and because of the higher manufacturing cost.
These are called “continuous coils because a whole row of coils is made from one strand of coil wire. Therefore the top of a coil is attached to a coil on one side, and the bottom to the one on the other side. Rows of coils usually run head-to-toe to minimize motion transfer. Several manufacturers have product lines featuring continuous coil innerspring units. One advantage they and some retailers cite is their durability.
Invented and patented in 1900 by James Marshall, pocket coils are unattached individual coils, each one in a fabric pocket. The principal advantages of pocket coils are conformability and elimination of motion transfer.
Each coil responds independently to weight placed directly on it. The coils are kept in place by stitching or welding the pockets together. This allows the coil array to closely conform to the contours of a sleeper’s body. Support is evenly distributed across the body. Wider points of the body, such as hips, shoulders, knees and elbows, do not carry more than their share of the body’s weight, so this relieves pressure points, which can be painful.
Since each coil does not pull down its neighbors, Marshall coils eliminate motion transfer. When one sleeper gets into or out of bed or moves around in bed, the other sleeper is not disturbed.
A newer development is dual coils, commonly described as coil-in-coil. The key patent for dual coils is by Sealy (Larry K. DeMoss, inventor) in 2010 (9). These are pocket coils where each coil is really a double coil, one inside the other. Each coil pair is made of one piece of wire. The outer coil is taller with fewer turns and is more responsive. The shorter inner coil has more turns and is firmer. The outer coil has the initial response, giving a soft, cushioning feel. When the shorter coil is reached, the response is firmer for underlying support. This configuration allows the innerspring to adjust to sleepers of different weights.
The latest major development in mattress coils is microcoils. These are small pocket coils, usually 1 to 2 inches high. Microcoils are used in comfort layers, even in latex and memory foam beds. Some models have several microcoil layers. Since they are pocket coils, they are very conformable. And since they are coils with internal airflow, they are cooler than foam layers. Now there are also mini-microcoils, with heights usually less than an inch. With the variance in heights and overlapping of categories, it would be helpful if manufacturers and retailers would work together on industry standard definitions for microcoils and mini-microcoils, even adding a term for the higher ones of 2 to 4 inches.
While considering the type of coils in a mattress, consider the gauge, coil count and arrangement of the coils as well as the type. Heavier gauge means more durability and firmer support. Higher coil count usually means more even support. Some innerspring cores have higher coil density and/or heavier coil gauge in the center part of the mattress, where most of the body weight is. When Some manufacturers say “nested coils,” they usually mean placed in a hexagonal array, which is more closely packed than a square grid, yielding a higher density.
1. Wikipedia, “Mattress” – http://en.wikipedia.org/wiki/Mattress
2. Utah State University, “Selecting an Innerspring Mattress” – http://extension.usu.edu/files/publications/factsheet/HI_08.pdf
3. Sleep Like the Dead – http://www.sleeplikethedead.com/mattress-reviews-coil.html
4. Sit’n'Sleep – https://www.sitnsleep.com/resources/article/all-about-mattress-coils
5. Bedrooms & More (Seattle) – http://www.howtoshopforamattress.com/mattress-coil-types.html
6. The Mattress Underground – http://www.themattressunderground.com/mattresses/support-cores/innersprings.html
7. Serta -
8. Easy Snoozing – http://www.easysnoozing.com/innerspring-mattress
9. Google, Patents, “Coil-in coil springs and innersprings: US 7908693 B2″ - http://www.google.com/patents/US7908693
A recent poll on our main website, Beds.org, showed that about 38% of our readers prefer a spring bed over all other types. While I definitely prefer a memory foam bed, obviously some people like springs better. So how do you know what to look for in a spring bed?
Personally, I am a very analytical person. I need to know what makes things tick. For that reason, I have developed a standard approach for evaluating almost anything I buy, from snacks to a house or a car. I always break the subject down into easy-to-swallow parts, and give each part a rating in my head, based on what I feel is the most important. I can apply this pattern to almost anything, including mattresses.
When considering a spring mattress, I look first at construction. Comfort is nothing without longevity. I want to know about what the springs are made of and how they are arranged. The first thing I like to examine is the spring gauge. Gauge is another word for diameter when measuring a spring. We are interested in the diameter of the steel wire used to make the spring, not the diameter of the coil formed with the wire, so to help keep the two separate, we use a different name for the wire diameter. The gauge of a spring uses a low number to signify a thick wire, and a high number to signify a thin wire. A 10 gauge wire is substantially thicker than a 20 gauge wire. When you coil this wire to make a spring, the thicker wire will last longer and reduce the likelihood of breaking down over time.
Next, I look at the spring layout. I will leave this in simple terms since there are so many options available here. The two primary types of bed springs are individually pocketed coils and what I refer to as spring networks. Individually pocketed coils are single springs which live inside of a pocket, exactly as the name suggests. Individual springs typically will not show the same longevity of a spring network using the same gauge springs, since each spring acts on its own and does not get assistance in bearing the load applied from nearby springs. The pockets which hold each spring are usually sewn together, but the springs themselves are not connected to each other. Generally this type of spring shows a great reduction in transferred motion over a spring network.
Spring networks have each spring connected to a platform at the top and bottom. The top and bottom platforms are also wire or spring steel. This is more durable in the long run since each spring uses the resistance of the springs next to it to handle the weight applied. The downside of this network is that you won’t see your weight being distributed quite as well as individually pocketed coils and that any movement on the bed is transferred easily to the entire mattress.
Now I consider what type of comfort layers the bed has. The comfort layers are generally what will determine the feel of the bed. Most manufacturers use the same spring base for a whole series of mattresses, and simply adjust the type and amount of comfort padding to create a new mattress feel. More padding and softer padding will obviously create a softer mattress. Some beds may have an 18 inch overall profile, but use a 6 inch spring. This does not really mean that there are 12 inches of padding. If the mattress is a double-top design (meant to be flipped over periodically) then you will split the padding thickness between the two sides of the mattress. Using a pillowtop or euro-top design also adds a little bulk. What you may actually see in this case is a 6 inch spring base, then 5 inches of padding on each side of the mattress. The remaining 2 inches will be absorbed by the material used to encase the comfort layers, such as the quilted cover. There is no doubt that a mattress with 5 inches of padding will be a soft bed overall, unless it is specifically designed to be both thick (for aesthetic reasons) and firm. In these padding layers you might see batting (loose-fill cotton or wool, typically quilted in a mattress cover), polyurethane foam, memory foam, latex foam, or other trademark-named foams (SealyFoam for example).
Of course there are other important factors, like price, warranty, return period, and so forth. I feel it is very important to know all about how to return, exchange, and replace a bad bed before I buy it. I always recommend (well, preach is more like it) that you do the same. It is much easier to learn about it in advance rather than to swear about it after a problem arises. In my experience, a good spring bed will have a 10-20 year warranty period. The sleep trial can be different on the same model of bed sold at different outlets, as this depends more on the retailer than the manufacturer. A good sleep trial will be 30-90 days.
By: Scott Braddam
A bed is something more than just furniture to sleep on. If this were the case, a mattress on the floor would be a bed. A bed is really a statement, a comfort, and art all at the same time. Personally, I am a minimalist. I like platform beds, and the simpler the bed, the better. My logic is that the less I have to coordinate my furniture, the more options I will have when I add new furniture to my bedroom. This is a perfect example of minimal yet functional furniture. As a bonus, this platform bed features storage drawers for whatever you may need to store there.
The platform bed pictured here is from South Shore, but represents a style used by many different manufacturers for this simple and effective design. The mattress sits atop a solid wood base (solid versus slatted, some platform beds use a type of plywood for this surface which is still a solid piece), and under this base are several drawers. The drawers make use of the ample space available under the bed without the hazard of things getting pushed so far under the bad that you would need to get on your hands and knees to get them out.
This particular design is about 1 inch wider on each side and 1 inch longer on each end that the mattress size it is intended for. I consider this a hazard, since walking too close to the corner of the bed late at night could prompt you to want to keep band-aids on your nightstand. Personally I own a very similar design to this one, only the platform is actually ½ inch smaller all the way around than the mattress, so if I bump the corner, I bump the foam, not the wood.
What I love most about the simplicity of a platform bed is the number of options you have for décor in your room. With a good platform, you can focus on linens and bedding, drapes and curtains, and fixtures in the room without the hassle of the coordinating the headboard or footboard design. In my case, the headboard is semi-custom, and makes no impact on the overall décor of the room. I coordinated the oak curtain hardware with oak dressers, a pair of oak nightstands, and finished out the room with antique brass lamps and hardware. If I (or more appropriately, my wife) decided to change the furniture in our room, a simple replacement headboard would suffice, for around $200-$300. This could save us $1000 or more on a complete new bed.
Tags: bedroom furniture, beds, furniture, platform beds, simple beds.