Choosing a mattress
The mattress for the comfortable user
The mattress is a personal thing. It's like shoes. Just as shoe size is strictly related to the size of the sole, the mattress is strictly related to the height, weight, constitution and health issues of whomever sleeps on it.
The purpose of a mattress is to provide support and comfort to the people who sleep on it. The support comes from bottom layer of the mattress, and the comfort comes from the top layer.
The relevant factors in deciding what mattress to choose are: your body type and particularities, your health particularities, your budget, the quality of the mattress. The mattress type (springs, latex, memory foam, or polyurethane foam) isn't such a factor.
It can not be stated more firmly (pun intended) that the saying "a firm mattress is good for the back" is an evil advice which should only be given to enemies. If you are slim then choose a soft mattress, if your weight is average then choose a medium firmness mattress, if you are overweight then choose a firm mattress.
To choose a mattress, go to the store, lie in your preferred positions on as many mattresses as you like, stay there for as much time as you can, and buy the one that feels best for you and that you can afford to pay without living your life to pay for it. When testing, follow the advice below.
A bed isn't tested by sitting on its edge, not for sleeping, anyway. When sitting, the entire weight of the body presses on your bottom (which then presses on the mattress), whereas during sleep only the weight of the bottom presses on the mattress, which means that this kind of testing makes the mattress feel much softer. Also, the edges of a mattress are its softest spots.
Is lying for a few minutes on a mattress a guarantee that you will make a good choice? No, but not lying on a mattress at all is more likely to lead to choosing a wrong mattress.
When laying on your back, your bottom and the middle of your back have to push in the mattress, and your head has to push in the pillow, all without causing pressure / pain to your bottom, lower back, middle of your back and neck; "middle of back" is about at nipple level, where the backbone is curved the most outward.
When you lie on a mattress that's too firm for you, your bottom sinks very little in the mattress, and your lower back stays too high to touch the mattress. This creates a gravitational pressure in your lower back, pressure which will cause pain after years or decades of sleeping like this. If you can't replace the mattress, a way to reduce this effect is to put some pillows under your calves or knees.
When you lie on a mattress that's too soft for you, your bottom sinks in mattress until your lower back starts pushing in the mattress. Therefore, your lower back has to support more pressure, and this will cause pain after years or decades of sleeping like this. This effect is reduced on a memory foam mattress because this is also deformed (= kept down) by your heat; still, if your bottom is too heavy for the mattress, the effect will still be there.
When laying on your side, your hip and shoulder have to push in the mattress, and your head has to lie on the pillow, all without causing pressure / pain to your hip, lower back, side chest and neck; "side chest" is about at nipple level.
You must use a pillow which fits both your body and the mattress that you are lying on. Try multiple pillows with the same mattress.
If while you relax on a mattress you start to feel sleepy after a few minutes, the mattress is a good candidate for the final decision.
Do this several times, weeks or even months apart, so that your body and mind adapt to all the mattresses.
A mattress should have:
According to this survey, the general opinion is that the highest owner satisfaction is for memory foam (81%) and latex (80%) mattresses, while the lowest is for spring (64%) mattresses.
There are mattresses with several zones of different levels of firmness. However, these zones are fixed in size, position and firmness, so they might not fit your body's height, structure and sleeping positions. The more zones there are, the easier it's for you to lay on the zones which are the opposite of what you need. If the cover is not removable so you can see where each zone goes, the issue is compounded.
When you consider the cost of a mattress (and of any accessories), think at the price that you are willing to pay each month for a mattress which will literally have your back.
You will probably change your mattress every 5 to 10 years, maybe with an average of 7. There are 7 * 12 = 84 months in that period, so multiple this with the amount of money that you are willing to pay each month. This should be the maximum price of your mattress.
See this for a way to determine if you can afford things in general.
Hygiene studies for different types of mattresses are conflicting, so don't choose your mattress type based on hygiene claims for that type.
For example, this study has found that foam mattresses contain more dust mites than spring mattresses. However, the authors recognize that another study has reached the opposite conclusion.
A foam's density is independent from its firmness. High density foams can be produced to be very soft, and low density foams can be made to be very firm.
For latex, the firmness is mostly proportional with the density. The firmness varies from extra-soft for a density of 65 kg / m3, up to extra-firm for a density of 95 kg / m3. However, for the same density, the firmness varies depending on the manufacturing process, and from manufacturer to manufacturer.
Density directly affects the durability, and therefore the support properties, of foam. A very high density foam (like latex) is much more durable than a very low density foam (like polyurethane).
Latex and memory foam density should be at least 65 kg / m3.
Foam firmness is described using a standard measurement value called IFD (Indentation Force Deflection), and is the number of kilograms of force required to indent a foam sample by a specified percentage (usually 25%) of its original thickness.
For example, to measure IFD, a 20 cm (= 8 in) metal disc presses a 10 cm (= 4 in) thick sample of foam until a 2.5 cm (= 1 inch) high indentation is created. The force in kilograms required to obtain this indentation is the IFD.
Lower IFD numbers indicate a softer foam, while higher values indicate a firmer foam.
The compression modulus (also called "support factor") is for IFD what acceleration is for speed.
The compression modulus is determined by dividing the IFD required to obtain a 65% tall indentation in the foam, to the IFD required to obtain a 25% tall indentation in the foam.
A common compression modulus for high quality foams is 2.5. This means that the firmness of the foam is higher the more it is compressed.
The surface firmness (at 25% tall indentation) shows the comfort feel of the foam, while the deep firmness (at 65% tall indentation) shows the support feel of the foam for the body (that is, the foam's ability to prevent the body from reaching the bottom of the mattress).
Bounciness and stability
Springs, latex, and non-memory foams have bounciness, that is, once the body moves on them they instantly change their shape. For side sleepers, this may lead to muscular activity and body movements to find a stable position, and this may result in a less deep sleep. Something similar happens if the mattress or pillow is too firm.
The slowness with which memory foam reacts when it's exposed to heat, both when deforming and when regaining its factory cast shape, leads to a lack of bounciness, and, for side sleepers, this provide very good stability to the body.
The lack of bounciness of memory foam affects sex because thrusting has no feedback / bounciness.
Heat retention is body heat which is retained by a mattress when you lie on it; because this heat is not absorbed by the mattress, it creates a discomfort by overheating the person who lies on it.
Foam mattresses are generally affected by this problem, with memory foam mattresses being affected the most. Heat retention is in fact the biggest disadvantage of memory foam mattresses, toppers and pillows.
Heat retention can be reduced a bit during the manufacture process by reducing the memory effect, or by drilling narrow, vertical tubes through the mattress.
Heat retention can be reduced by sleeping on a mattress cover made with bamboo fibers.
If you feel that your mattress retains heat, you could try to sleep with very thin pajamas or none at all, and cover yourself with only a sheet (not a blanket or duvet).
Spring mattresses are theoretically immune to this issue since they are mostly empty around the springs. However, modern spring mattresses have a foam layer at the top, layer which retains heat.
Why does heat retention happen? Why do some mattresses feel cool while others feel hot?
You may hear it has to do with ventilation / air circulation, but the actual reason is thermal comfort, specifically, heat balance (= body generated versus lost through materials).
Thermal comfort depends on how much heat your body is generating and how much heat it loses through the various materials that cover you. It also depends on what the temperature is beyond the materials that cover you, and on how fast the room you are in loses heat to the outside (which, again, depends on the temperatures inside and outside, and on the thermal insulation of the home).
Specifically, thermal comfort depends on the thermal conductivity of the materials, that is, on the thermally insulating properties of the materials that cover you (where the mattress is covering your back).
Foam is a good thermal insulator because it traps air inside, air that can't easily circulate to escape to the outside (or come in contact with the mattress cover). A good thermal insulator has a low thermal conductivity, which means that it transmits little heat from you to it and then to the outside.
You can read more about thermal comfort here.
Latex is a rubber with excellent elastic properties, which can be used for both the support and comfort layers.
The benefits of latex are: it's supportive yet flexible, has excellent bounciness (which people like during sex), it's lifetime is much longer than polyurethane's, doesn't have the heat retention of memory foam (so it feels cooler during sleep).
Latex quality varies significantly. Something which is called "100% latex" could contain less than a third natural latex, while the rest is synthetic latex (to reduce the price); you can't see the difference just by looking at latex because all the components are blended. Considering that a slab that's made from 100% natural organic latex costs, for example, 4 times more than a cheap latex slab, you can see why most people shouldn't reject latex which is not all natural.
Beware that just because something is labeled "natural" doesn't mean that it is, especially if it's cheap (to attract buyers).
Latex, natural or synthetic, emits a bad smell, like foams generally do. The intensity of the smell depends on the quality of the foam, with high quality foams having the least intense smell.
Some manufacturers call their mattresses "latex" even though they have only a thin layer a latex. In order to benefit from the comfort properties of latex, it should be used in a layer that's at least 15 cm (6 in) thick.
Before you spend the money, make sure that you are not allergic to latex!
Memory foam (also called viscoelastic foam) is a foam which slowly reacts to heat in the sense that it slowly deforms to take the shape of a body which sits on it, slowly recasting itself to the shape of the body, and slowly regaining its factory cast shape once the (heat of the) body moves away. As the body moves on the mattress, the memory foam slowly adapts to the new position of the body, not instantly like in non-memory foams.
A memory foam mattresses is not made entirely from memory foam because while it provides good comfort, it lacks supportive properties (= has a low compression modulus). Memory foam is normally used only for a thin layer (5...10 cm, 2...4 in) at the top.
People who first try a memory foam mattress may find its motion stabilization to be unpleasant. When the memory foam takes the shape of the body, the depression which occurs in the mattress may be too deep (depending on how thick and reactive the memory foam is). Because of this depression formed under the body, moving around and getting up from the mattress requires more effort than on a non-memory foam mattress.
This gives a feeling of being in a caught in a hole (in the ground). However, after a few weeks the body adapts to the new feeling and it starts to enjoy the stability.
Not all memory foams are equal. Some react more intensely than others at the same amount of heat. As the reaction to heat increases, so does the heat retention of the foam, and heat retention is unpleasant in a warm environment. Tempurpedic mattresses are known as having the highest memory effect, but also the highest heat retention. I had a Tempurpedic (memory foam) pillow which made my nape sweat during the summer, but my current Magniflex (memory foam) pillow only feels warm (but not hot).
Humidity, either from the air or from perspiration, is absorbed by memory foam, which causes it to sag.
Stomach sleepers should avoid memory foam because they would sink in the middle, which would put pressure on the back.
Polyurethane foam has a bad reputation for being toxic compared to 100% natural latex, but its quality varies greatly.
Polyurethane foam is much cheaper than latex and memory foam.
A common density of polyurethane foam is 25...35 kg / m3, so it's much lighter than latex and memory foam.
Memory foam is a type of polyurethane foam that contains additional chemicals to increase its viscosity and density.
Fancy-named foams that are not latex, are some type of polyurethane.
This tutorial is mostly referring to foam mattresses because they are easy to describe through the characteristics of foam. Spring mattresses contain springs made of steel (some are made of wood), and the mechanical characteristics of steel are not found on mattress labels, so they can't be described.
Foam mattresses are not better than spring mattresses; each type has it strengths and weaknesses. Arguments that make foam mattresses look generally superior to spring mattresses are made in order to profit from your lack of knowledge.
The only comfort-related disadvantage that spring mattresses have is that they contain low density foam (like polyurethane) and low density textile (like cotton), layer that breaks much faster than the springs below. Steel is the last thing to break since it's much more durable than any foam or textile material.
If you want a durable spring mattress, look for one whose springs are covered only with felt (which is a very high density textile). It's likely that you will not find one like this, so look for a spring bed foundation (/ box spring); sadly, even these contain polyurethane, nowadays. On top of this, put a (latex) mattress. This will allow you to change the mattress when it no longer provides you comfort, without throwing away the springs.
A disadvantage not related to the comfort of spring mattresses is that generally they are not vacuum packed (in small packages), like foam mattresses are, although some are.
Another disadvantage not related to the comfort of spring mattresses is that they are a bit noisier than foam mattresses. This is due to the noise made by steel when it's (de)compressed.
Modern spring mattresses are made with pocket springs where each spring is individually wrapped in a textile pocket. Since there is no steel connecting the individual springs, such a mattress is very good at keeping motion in the place where it happens, instead of propagating it on the other side of the mattress, meaning that if you get up during the night, your partner will be less likely to be awoken by the movement of the mattress.
There are manufacturers which have mattresses that have separate foam layers which can be swapped to provide you the firmness that you need.
There are manufacturers which have mattresses that are split in half, one half for each person that sleeps on the mattress. You can unzip the cover of such a mattress and expose its internal foam layers. You can then flip over either half (or even both), so that each person has a half-mattress with a different firmness than the other person. The foam layers are usually glued together, so you can't swap them around.
In order for the two halves to feel as a single mattress rather than two smaller ones, the mattress cover has a foam padding layer which is thick enough to bridge the gap between the two halves.
If you think that this padding is not enough, it's possible to buy a mattress bridge, but these are normally thick and can be felt. A mattress bridge is a filler plank made from a soft material, which is put in and above the gap between two mattresses, under the cover.
A split mattress also gives you the possibility to replace only half of it at a time. For example, you can start by buying a 180 * 200 cm (72 * 80 inches) mattress; later you can replace half of it by buying a 90 * 200 cm (36 * 80 inches) mattress (and taking its cover off).
A split mattress is important for people who sleep together and have significantly different physical constitutions, but also for people who either sell or rent an apartment / house which includes the mattress.
Here is how you can make your own mattress from parts.
Would a DIY mattress cost you less than a ready-made one that's bought from a store? Probably not, at least not when you first start doing this, but since you can change the parts individually, it's likely to cost you less in the (very) long term. Another advantage is that you can customize it very precisely to your needs, without wasting time going around through the stores to test countless mattresses and still not finding the right one.
You will have to buy several layers of latex, each with a different density (60...95 kg / m3). Remember that for latex the firmness increases with its density.
You should buy the layers one at a time in order to keep the cost as low as possible (because you can stop buying when you reach your target), and to help you when you don't know the density / firmness of the latex.
If you can't find bare latex cores, you could buy normal mattresses that have their entire core made from a slab of latex. This means that while you would pay extra for the cover, you could either keep or remove the cover off the mattress.
If the mattress is for 2 people, the bottom layers could be split in half (= made from 2 parts), one for each person. This way, each part could have a different density / firmness, and could be changed separately if it becomes damaged, which in turn would reduce waste and long term costs. This also allows you to stack the halves on top of each other in order to see how it feels to have a much thicker layer with the same density, before you buy the rest of the layers.
If the bottom layers are split in half, the top layer should be full size in order to bridge the split below it; this top layer should be at least 7 cm (3 in) thick. Memory foam doesn't provide support, so there must be a full size latex layer under it.
The thickness of a layer is not important because you can use fewer or more of layers. If you can find thin latex layers which are 5...8 cm (2...3 in) thick and have different densities, you could fine tune the feel of the mattress by interlacing several of them.
First buy a layer of latex whose density depends on your weight distribution:
Side sleepers should prefer softer layers. Stomach sleepers should prefer firmer layers.
Once you lay on this layer, if you think that its firmness is:
Once you lay on these two layers, and you switch them around to see which combination is better, if you think that their firmness is:
Once you're done with the latex layers, if you like the motion stabilization feel of memory foam, add a top layer of memory foam. Its thickness should be 4...7 cm (2...3 in). Stomach sleepers should avoid memory foam because they would sink in the middle, which would put pressure on the back.
How thick should the mattress be? For me, a slim person, when laying on a 16 cm (6 in) thick latex slab with a density of 65 kg / m3, I can feel the slats of the bed foundation. If there are 2 such slabs on top of each other, the floating sensation is spectacular.
If you have to increase the height of the mattress, and you can't change the bed foundation, add at the bottom of the mattress a layer with a density which is higher than the density of the existing bottom layer; the same density is also fine.
If you don't have the budget for an all latex mattress, you could make its base from (firm) polyurethane foam. Do remember than the durability is lower for the polyurethane foam because of its much smaller density.
Is it fine to have a high density layer on top of a low density layer? Latex lifespan is getting reduced with density: low density latex has a shorter lifespan than a high density latex. Lifespan is also reduced by the strength of compression (= force applied over a small area). Since the bottom layer is constantly compressed by the top layer, some people think that it's wrong to put a high density layer on top of a low density layer.
The top layer, on which you sit directly, is compressed only over the area of your body. At the same time, the top layer takes over your direct weight and distributes it on a much wider area, which means that the compression strength of the bottom layer is significantly lower than that of the top layer, which means that its lifespan is higher than if it were the top layer (and directly compressed by your body).
While you could make a custom cover for all the layers, you could also wrap them in a mattress pad (or two) in order to protect them and hold them together better. This is important for the edges, which have a tendency to raise when you sit on the mattress, so they need something to hold them together. If you use a mattress pad, which doesn't normally cover the bottom of the mattress, you should put a thick textile layer under the mattress in order to protect the latex from humidity and from breaking into small airborne particles (due to aging).
Mattress pads made from Tencel are good at keeping humidity away from the mattress.
Make sure that your bed can support all the weight of all the mattress layers and of the people who will sleep on it.
A DIY mattress will be very difficult to turn or flip (because it has several parts and no handles).
On the other hand, smaller mattresses can be maneuvered easier than larger mattresses. A full latex mattress can easily exceed 50 kg (110 pounds), so even with a cover with handles it's difficult to maneuver.
There are various types of bed foundations: solid plank, plank with many small (vertical) holes all over it, wood slats, springs.
A bed foundation made made from a solid plank is a bad choice for any kind of mattress because it blocks any ventilation, but it's especially bad for foam mattresses.
A foam mattress should be put on a bed foundation which has good ventilation, like a plank with many small holes all over it, or one which has wood slats.
A mattress should stay on the bed foundation as flat as possible, so avoid putting a mattress on a bed foundation whose slats are spaced at a significantly greater distance than the width of the slats.
A bed foundation made with springs is meant to complement a relatively thin mattress. Because the steel of springs is much more durable than the other materials used in a mattress (like foam), when the mattress has to be replaced, the base can be kept, so the resulting waste is significantly reduced (and this also reduces the cost of the replacement).
A bed foundation should allow you to lift the mattress with ease, so make sure that the mattress handles are not covered, and that you have space which allows you to lift and turn the mattress.
The top of the mattress should be high enough so that you can get down from the bed rather than get up from the bed, that is, you should not need to force your knees to raise your body from the bed. An average height is 60...65 cm (24...26 in).
If you want to make a solid custom bed foundation, make its legs and the frame which sits on (and around) the legs from wood beams that are 8 * 8 cm (3 * 3 in) thick. Between the bottom of the legs and the frame, put small beams at 45 degrees to provide the legs resistance to longitudinal and lateral movements, like it may happen during sex. For a 2 people bed, add 2 beams, from head to toe, that are spaced equally along the width of the bed foundation. In order to provide support for the mattress but still allow it to ventilate, on top of the beams, left to right, put wood slats that are 2...3 cm (1 in) thick, 5 cm (2 in) wide and 5 cm (2 in) apart.
You might want to make a double bed foundation from two pieces instead of a single monolithic one, in order to avoid any risk that it would not fit through some area. Breaking parts of walls is not desirable.
The pillow is as important as the mattress itself, and should only be chosen in pair with the mattress.
A pillow should be made from memory foam in order to provide stability (not bounciness) to the head during sleep, and to not push back into your nape. Since memory foam is deformed by heat, it doesn't push back into your nape.
There are pillows which are solid blocks of foam, but there are also ones that imitate feather filled pillows, pillows which are filled with shredded foam. From these, you can remove some of the foam in order to adjust the pillow's height to your liking. In the case of shredded latex, the bounciness of solid latex is reduced because the latex fragments move, in part, to the side.
A wavy pillow is designed to have its middle thinner than the top and bottom sides. This allows the head to sink in the pillow more than the neck, and so the head, neck and backbone stay straight in line. Usually, the sides of the pillow have different thicknesses so that if one of them doesn't fit your neck, the other might.
For pillow's made of solid foam (rather than small pieces), for people who sleep mostly on their back the pillow height around 8...12 cm (3...5 in), and for people who mostly sleep on their side the pillow height around 10...12 cm (4...5 in).
A little story about bouncy-foam pillows
For about 8 years I have slept on a latex pillow. The pillow was great, it had no irreversible deformations; it only got a little yellow and a bit more brittle.
From some point onward, occasionally, I started having extreme neck pain manifesting as hot stabbing flashes when I was turning my head. If the movement was very slow, the pain was reduced significantly.
After 8 years I've replaced this pillow with a memory foam pillow. The pain virtually disappeared.
I tried again the latex pillow and the pain reappeared the next day. I then realized that the latex was pushing into my nape, so this may have been the cause of the pain. Another possible cause was that the bounciness of the latex was forcing me to turn my head in order to find a stable position, turning which led me to sleep with my neck twisted.
The odd thing was that the latex pillow was much more comfortable than the memory foam pillow when I put my head on it, yet it had an invisible opposite effect on the long term.
I've repeated the experiment with a pillow which had one half made of memory foam and one half made of bouncy foam, and the result was the same: when I was sleeping on the bouncy part, the pain reappeared.
The moral of the story is that if you have neck, back, hip, shoulder or even knee pain, be sure to pay attention to how you sleep, on what you sleep and what is the position of your body for long periods of time on the bed, sofa, chairs, and even toilet (if you sit for long times on it).
For instance, if you sleep on your side, on a firm mattress, the hip on which you usually lie may start hurting.
Never assume that a comfortable position is a correct position. Because the skeleton is a connected mechanism that acts as a whole; for example, a wrong position on one end of the backbone may have a bad effect on the other end. A too firm or too soft mattress or pillow may also be the cause of your problems.
Lower back pain can occur because you sit the wrong way on a chair, like with the sole of a foot on the chair, therefore forcing your backbone to bend laterally.
Sitting with the calf or ankle of one foot over the knee of the other (which rests on the floor) may cause pain in the knee of the twisted foot, but also in the calf of the foot which is resting on the floor.
The biggest problem in understanding the cause of your problems is that the pain may occur much later than the cause. For instance, you may be sleeping in a bad position, but the pain may start occurring only years later.
You could also think that back or neck pain is age related even though it may be your bad posture or mattress / pillow, something to which you may be accustomed and say that it's good for you. Being accustomed to it doesn't mean that it's good for your body, even if it's comfortable for the moment.
Avoid sleeping on your stomach because this position puts great pressure on your neck due to the fact that you need to keep your face turned 90 degrees relative to your backbone (in order to be able to breath).
Generally, the user satisfaction increases as the thickness of the mattress increases. For the average adult, the thickness of a mattress should be at least 20 cm (8 inches).
Your mattress must have a firmness which fits your body, and must not be sagging, that is, it must not have permanently depressed areas (especially where your bottom is).
If your back or neck hurts, it may be that your mattress is bad, or that your sleeping position is bad. You have to sleep with your body straight. If you are used to sleep on your side, the mattress has to be soft so that your hip and shoulder can easily sink in it and therefore allow your backbone to be straight. The way you sit on chairs may also be a cause of back or neck problems; you have to sit with your back and neck straight and with your soles on the ground.
A mattress topper should have 5 to 10 cm (2 to 4 inches). More than this would give you an unpleasant sinking feeling because a topper is made to provide comfort, not support to the body.
If you use separate mattresses for each person, you may feel the separation between them even if you use a mattress topper. In this case you can use a mattress bridge.
You should buy a mattress only if it has a removable cover so that you can see what the layers inside are, and to be able to wash the cover in order to remove the bad smell released by foam and trapped by the cover.
You should always use a mattress protector (which is like a moisture resistant sheet) to protect the mattress from body humidity.
Oeko-Tex 100 is a certification for the chemical safety of textiles for people.
If you want to sleep well and feel relaxed in the morning then remove stress from your life, do physical exercise, eat properly, and sleep 7...9 hours a day (depending on your body's needs); "sleep" means sleeping, not just laying (consciously) in bed. The muscular tension created by stress can't be reduced by a mattress, no matter how expensive.
I've heard that brand X makes super-mega-ultra great mattresses that make you fall asleep in the showroom as you try one, and have features Y, Z and W that I've heard I really need. Should I buy one?
You know what mattress is good for you? The one that you lie on, and out of the tens that you've tried feels the best to you, fits in your budget and has a warranty which fits your needs (if the manufacturer fulfills that warranty, especially for its inner layers). Keep in mind that, usually, the lifespan is much shorter than the warranty, and it's generally between 5 and 10 years; make sure that you read this about warranties and lifespan.
Also, buy from a manufacturer which describes in as much detail as possible the internal structure of its mattresses, and the materials that they use.
How can I ensure that a mattress has Oeko-Tex certification?
Textile manufacturers and their products can have Oeko-Tex certifications. These certifications are different things.
To be certified, a mattress must have a label (with green, orange and black text) stitched on it, label which represents the Oeko-Tex certificate. This label contains the text "Confidence in textiles". If the label contains the text "0904046.O", it means that the mattress is class 2 certified, meaning that it's not expressly certified as being safe for babies.
Oeko-Tex says that in order to get their certification it's required that all the components of an item meet the required criteria without exception (meaning, the outer material, sewing threads, linings, prints, buttons, zip fasteners, rivets).
If you want to verify that a manufacturer is not falsely attaching an Oeko-Tex label to their products, verify that their name is on the Oeko-Text website.
Are metal beds and mattresses harmful to people because they amplify radiowaves?
There is no scientific evidence of this happening.
The people who claim that metal is harmful are usually using a guest blog article and its linked study. They usually have something to sell you: foam mattresses, wood beds and even devices that protect you from radiation.
The study itself is only a correlation of other studies, not a direct study, and is analyzed here.
If you look at the actual study, you'll see a weak correlation between the bias of the sleeping positions in bed and the bias of the cancer-correlated sleeping positions. Specifically, the bias of the sleeping positions in bed is about 1.38 for women and 1.96 for men. The bias of the cancer-correlated sleeping positions is about 1.07 for women and 1.13 for men, so far away from the same ratios.
A proper study would directly look at how many people sleep on foam and spring mattresses, in the same geographical location, and how many people in each category have cancer.
For details, read the Skirts don't cause cancer principle.
Sleep Like the Dead = Information about anything related to sleep, review aggregations.
Most of the companies below sell mattresses through the Internet, which allows them to avoid paying some costs, so they claim to have much lower prices than in a showroom, at the same quality.
DiyMattress = Latex for DIY mattresses. Uses Latexco cores.
EuropeanBedding = Latex mattresses. Great information about mattress. Uses Latexco cores.
John Ryan = Great information about the mattress construction and industry.
Magniflex = Mattresses that are split in two halves which can be flipped over independently. I have verified their Oeko-Tex certification (though, sadly, not helped by the manufacturer), using the manufacturer's name, not the brand name.
SleepingOrganic = Latex mattresses. You can create your own latex mattress from 2, 3 or 4 layers, each either full size or split in half.
Rest Performance = Smart mattresses which use electronics to monitor who sleeps on them, and to adjust their firmness.
Sleep by Number = Smart mattresses which use electronics to monitor who sleeps on them, and to adjust their firmness.
Artilat = Latex core manufacturer.
GommaGomma = Foam core manufacturer.
Latexco = Latex core manufacturer.
LatexGreen = Latex core manufacturer.
TalalayGlobal = Latex core manufacturer.
Tencel = Textile fabric manufacturer.
VitaTalalay = Latex core manufacturer.