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Memory Foam Guide: A Buyer’s Guide to Choosing Memory Foam
How to Choose a Memory Foam Mattress or Memory Foam Topper Pad
There are many reasons to choose a memory foam mattress. Once you have decided
to buy a memory foam mattress or mattress pad topper please use our simple guide
to help you in your selection. Here are the major areas of consideration:
• Reasons to choose memory foam: memory foam has been engineered for
comfort.
• The density of the memory foam: The density of the memory foam
determines the foams quality and feel.
• The height of the memory foam: Different heights are more appropriate for
those who weigh more.
• How much you weigh: Memory foam is not ideal for those who weigh over
250 lbs.
• Warranty issues: Most memory foam products come with a warranty.

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The Development of Visco­Elastic Memory Foam and It's Uses
Memory foam was first developed by NASA,
the National Aeronautics and Space
Administration. They describe their
purpose as "NASA's mission is to pioneer
the future in space exploration, scientific
discovery and aeronautics research". They
required a seating material that would
reduce the impact of the g‐forces at the
time of take‐off and cushion the astronauts
during their long journey into space and
back again. Visco‐elastic memory foam was
a scientific discovery made by NASA to
fulfill this objective.
The foam was then adapted by the Tempur‐
Pedic® Company for special needs hospital
patients such as those who had been
bedridden for long periods of time, as well
as for other patients in hospital burns units
who needed additional cushioning.
From this "special needs" use it was eventually adapted and offered to the public as
a specialty mattress product. Tempur‐Pedic promoted it as a bedding product for
those who wanted relief from "pressure points" which includes those who suffer
from arthritis.
By now everyone has seen the Tempur‐Pedic advertisements showing a child
jumping up and down on a bed next to a wine glass that doesn't move or spill. This
demonstration showed that memory foam, unlike regular inner‐spring mattresses,
deflects motion. If one partner moves on the bed, the movement is not transferred
to the other partner. This deflection of motion is another advantage of memory foam
over conventional mattresses.
In addition, visco‐elastic foam gently supports the body just where it needs
supporting. It is thermal sensitive and responds to the body temperature of the
sleeper. The foam "gives" right where it needs to "give" and offers support where it
needs to offer support.
The Memory Foam Experience
Those who have slept on a memory foam mattress report they feel “like I am
sleeping on a cloud of comfort.” This is why there is the claim that memory foam

4. gives relief from pressure points. They report that they have slept in pain for many
years and are now not experiencing pain and pressure throughout the entire night.
In addition, it gives good orthopedic support contributing to the floating experience
often reported. This is the reason customers say that they don’t “toss and turn” so
much in the night.
Because memory foam is a temperature sensitive material it can be heat generating.
For this reason it is not ideal for those who "sleep hot". But there are certain
patented fabrics which help to neutralize the heat of the memory foam, such as
CoolMax® fabric. Cotton sheets are also recommended. And some memory foam
have been engineered to produce a slightly more cool temperature.
Wikipedia Definition of Memory Foam
“Memory foam is made from polyurethane with additional chemicals that increase its
viscosity level, thereby increasing its density. It is often referred to as visco­elastic
polyurethane foam. Depending on the chemicals used and its overall density, it is
firmer in cool temperatures and softer when warm.
Higher density memory foam reacts to body heat which allows it to mould itself to the
shape of a warm body within a few minutes. A lower density memory foam is pressure­
sensitive and will mould more quickly to the shape of the body. The example often used
to demonstrate its properties is that a hand pressed into the foam and then removed
will leave a clear impression in the foam.”
IDF: Indentation Force Deflection
In order to arrive at a simple qualitative indicator, Indentation Force Deflection
(IFD) was coined as the technical ‘softness’ or ‘hardness’ of a given piece of foam.

5. This was formerly known as the ILD or Indentation Load Deflection. IFD measures
the pounds of force required to indent a 4‐inch‐thick sample of foam 25% of its
thickness. This is the most accurate number to look at for gauging firmness but it is
usually not available.
This is because constructed bedding complicates the rating systems. A
manufactured mattress or piece of furniture may be composed of several different
foams encased in a specific stretch‐tight cover. The combination of foams with
different IFD’s, quilting products and stretch‐tight fabric covers will give an adjusted
or effective IFD for the finished product, but such measurements are not always
practical because each single product style would require its own specialized
measurement. This makes it difficult to compare one mattress to another. For
practical purposes, it is easier to compare memory foam by comparing the density
of the memory foam.
Different Types of Memory Foam: An Explanation of Memory Foam Density
The difference in memory foam quality basically comes down to differences in the
density of the foam. Different densities produce different experiences of the
cushioning effect of the foam. The foam generally comes in densities ranging from 2
lb density to 5 lb density, though there are some 6 lb to 8 lb density foams available

6. out there. The more dense the memory foam is, the heavier and the more expensive
it is.
Many people generally assume that the "best memory foam" would be the most
expensive and the most dense foam. But this is not the case. The best memory foam
is the most comfortable memory foam and the density of the most comfortable
memory foams are in the middle to high range, from 3 lb to 5 lb.
The 2 lb memory foam is generally manufactured in China and is sold in most
department stores as genuine memory foam, which it is. But it is not high quality
memory foam and will not give the true memory foam experience. In fact, it is more
similar to normal polyurethane foam with some slight “memory” properties.
The denser the memory foam is, the longer it holds impressions. This is the
"memory" feature of the memory foam. To enjoy the true memory foam experience
it is good to use memory foam that is at least 3 lb density. But the higher density
memory foam holds the impression for quite a bit longer. The more dense the
memory foam is, the longer it holds the impressions.
Some people have reported experiencing discomfort when they move from position
to position on very dense memory foam. The reason for this is that as they move
from one position to another, the foam holds the "memory" of their previous
position and as they turn they feel they are falling back into the "memory"
indentation of the old position. They feel they have to pull themselves out of one
position and into another. In addition, very dense foam generally has a stiffer,
denser feel to it.
This is NOT the experience of the 3 lb, 4 lb and 5 lb memory foams. With these
densities, as you move from position to position, the foam gently moves with you.
The gentle reaction of the foam as it moves with you gives the softer feeling of
floating often reported by those who sleep on memory foam.
How to Choose Between 3 lb, 4lb or 5 lb Memory Foam
Any of these three weights would be a good choice. But what is the difference in the
feel of each? The 3 lb and 5 lb memory foams tend to be slightly firmer, each for a
different reason. The 4 lb memory foam is softer. This is our top recommendation.
The 3lb memory foam is slightly firmer because it has a little less “memory” and
therefore doesn't have quite as much "give". The 5 lb density memory foam is a little
firmer because denser memory foam in general tends to be firmer, with a slower
"recovery" time, ie the foam does not recover as quickly as lighter foams.
The 4 lb memory foam is just right. It has just the right amount of "give" with a good
"recovery" time, so the foam moves with you as you move from one position to
another. There is also a lot of positive feed back on 5 lb memory foam. The reason

7. customers are also very happy with 5 lb memory foam is that it has the most
luxurious feel and it’s the most durable.
Memory Foam Height Considerations
Another consideration when buying a memory foam mattress or topper is the height
of the memory foam. Memory foam toppers come in heights ranging from 2 inches
to 5 inches. In the construction of memory foam mattresses 2‐5 inch memory foam
layers are also used.
Though a memory foam mattress is 10‐12 inches in height, it is not ALL memory
foam. This is because it is not necessary for a memory foam mattress to have over 4
inches of memory foam. The memory foam is always the top layer of foam in a
memory foam mattress. In addition, there will be base layers of either polyurethane
support foams or latex foam. For example, a 10 inch memory foam mattress will be
composed of 2‐4 inches of memory foam and 6‐8 inches of base foam. The most
luxurious memory foam mattresses are composed of a memory foam top layer and a
latex base foam.
A 2 inch memory foam topper adds a soft layer to a regular mattress. A 3 inch
mattress pad topper adds an even softer layer and a 4 inch layer will give a slightly
richer memory foam experience. The thicker toppers are recommended for those

8. who weigh more. NOTE: Memory Foam is not designed for those who weigh
over 250 lbs.
In terms of the “memory foam experience”, there is no difference between a 4 inch
memory foam layer and a 5 inch layer.
Whether to Choose a Memory Foam Topper or a Memory Foam Mattress?
If you are in the market for memory foam and haven't decided on whether you want
to buy a new memory foam mattress or whether you want to buy a memory foam
topper, here are a few considerations.
If you have recently purchased a new mattress or if your mattress is in very good
condition then we recommend that you add a memory foam topper to your existing
mattress rather than go to the big expense of buying a new memory foam mattress.
If your mattress is particularly firm, then choose a 3 or 4 inch memory foam topper
to go on top of it. If your mattress is softer, then a 2 or 3 inch topper should be good
enough. In addition, it will be necessary to use a mattress pad cover to cover the
new topper.
If you have a mattress with indentations then it is better to buy a new memory foam
mattress rather than to put a memory foam topper onto an old mattress.
What Do We Recommend for Those Who Weigh over 250 lbs?
Memory foam is not for everyone. It is not recommended for those who weigh over
250 lbs. This is because heavy weight will break down the foam very quickly. There
are other foams that have been engineered for heavier weights. These include very
dense polyurethane foams and latex foam.
Another recommendation for those who weigh more is to use a memory foam
topper with a latex topper underneath. The latex topper will offer added support to
the “memory foam experience”. In fact, this is the most ideal topper combination for
most people: a memory foam topper on top of a latex base topper. In the case of
heavier people, the memory foam layer will have to be replaced regularly, perhaps
as often as once a year.
Memory Foam Warranties
In general, memory foam toppers will last 5‐10 years with the denser, heavier foams
lasting up to 10 years. It is not recommended that memory foam be washed or made
wet in any way. It will spoil the material. If a memory foam mattress or topper is
exposed to water it will nullify the warranty.

9. For this reason it is always good to use a mattress pad cover with your memory
foam topper or mattress. A mattress pad cover will protect the memory foam from
exposure to moisture from body sweat or liquids. Some memory foam warranties
are nullified if the product is not used in conjunction with a mattress pad cover.
Other Memory Foam Products....
There are many other memory foam products to choose from: Including memory
foam pillows, memory foam folding guest beds, memory foam lumbar support
pillows, memory foam body pillows etc. Most of these products are designed using
the memory foam density that most suites the product. But in the case of the
memory foam pillow it is possible to choose density and standard, queen and king
size.
Most memory foam pillows are formed in a "contour " design. This design can be
used in three different ways allowing for three different positions: side sleeping,
back sleeping and stomach sleeping.
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