Mattress Ratings >> Memory Foam Mattress Ratings
Memory Foam Mattress Density: Higher Vs Lower → Based on Data From Over 4,380 Owners
Page last updated April 20, 2010
Memory foam density is something you've probably heard of in your shopping and research. It indicates how much the foam weighs. For example, 5 lbs./ft density foam means that a cubic foot of this foam would weigh five pounds.
A variety of densities are available in memory foam mattresses.
To help you determine which density may be right for you, we compare below, based on collected owner data, higher density
foam (namely 5 lbs./ft or higher) with less dense
foam (namely 3 lbs./ft and 4 lbs./ft.).
Comfort
Less dense memory foam mattresses rate slightly
better in regard to comfort for people as a group.
The main reasons for this are that lower density foam is at least somewhat easier to move on and has less temperature sensitivity, say owners. Also, our
data indicates that people who do not weigh much (110 pounds
or less) often do not find the higher density foam comfortable because
its properties do not allow them to sink enough into the
mattress to achieve adequate comfort.
Slight advantage: lower density
Pain Relief
All memory foam mattresses, regardless of density, rate well in regard to pain relief, including relief of back, shoulder and hip pain. However, while higher
density memory foam may be slightly less comfortable to people
as a group, it may be better for the reduction of pain, especially
back pain.
Owners of higher density mattresses, such as Tempurpedic®, report somewhat more back pain relief than do
owners of mattresses that use less dense foam. For example,
a significant number of Tempurpedic® owners who have a history
of back pain say that they experience less pain when in bed
and even during the day since they have been sleeping on their
Tempurpedic®.
Slight advantage: higher density
Durability
In regard to durability, it appears
that higher density memory foam provides somewhat
better durability / longevity.
Based on the data, owners with mattresses of higher density foam, namely 5 lbs./ft or higher, can generally expect their
mattress to remain supportive and comfortable for around 5-10 years.
About 10-20% of the time, however, higher density mattresses lose comfort and
support sooner than five years due to premature sagging and or softening.
Long-term owner data for memory foam mattresses in the 3 lbs./ft and 4 lbs./ft density range
is far less complete than is the case for higher density beds. However, based on the limited data collected, less dense memory foam beds should be expected to have a shorter lifespan, probably in the 4-8 year range. There are instances, however, of lower density beds losing comfort and
support prior to four years due to sagging and or softening.
Advantage: higher density
Price
The price of a memory foam mattress is often linked to its density. The more dense the memory foam, the more expensive the mattress usually is.
In fact, a fairly reliable and easy way to determine the density of a memory foam mattress is to look at its price.
Higher-priced brands will tend to use higher-density memory foam (5 lbs./ft or greater in significant quantity); medium-priced brands will tend to use mostly medium density (4.0 lbs./ft); and lower-priced brands will tend to use mostly lower density (3.0 lbs./ft).
Advantage: lower density
Off Gassing / Initial Odor
Our data suggests that, generally speaking, the more dense a memory foam mattress is the longer and / or more strongly it will off gas. More info: memory foam mattress off gassing.
Advantage: lower density
Sensation
Higher density memory foam slowly adjusts to one's body weight and temperature. As a result, there is often a "melting in" and strong contouring-to-the-body feeling; most owners of these mattresses like these aspects or at least learn to appreciate them. A small percentage, however, do not like it and say it is like sleeping in "mud" or "quicksand."
Less-dense foam overall, by contrast, has fewer complaints by owners in regard to its "feel" which is more conventional.
Advantage: lower density
Ease of Movement
Owners of lower density foam mattresses report less difficulty moving on the bed than owners of higher density foam beds. This is probably mainly because lower density memory foam offers less resistance and does not contour as strongly to the sleeper's body.
Advantage: lower density
Weight
Less-dense memory foam mattresses weigh less than more-dense mattresses and are therefore easier to move and transport. Changing the linens and making the bed is also easier.
Advantage: lower density
Motion Isolation
This refers to how well the bed keeps the movement of one person from being felt by another person on the bed. Both densities perform very well on this issue, but higher density isolates movement almost entirely.
Slight advantage: higher density
Sleeping Hot
Our data shows that there is about twice as many reports of high density mattresses acting as a heat trap than is the case for low density beds. In addition, low density memory foam beds are generally only somewhat more likely to "sleep hot" than other mattress types, such as innerspring and air. More info: memory foam mattress and heat.
Advantage: lower density
Reputations of Brands
A mattress brand / company usually sells either higher or lower density memory foam beds, but some sell both. Owner data suggests that you should be able to find a reputable company / brand regardless of the density you are interested in. More info: memory foam mattress reviews / ratings summary.
Advantage: tie
Warranty
More-dense memory foam beds universally have at least a 20-year warranty; and usually the the first 10 years are non prorated. Less-dense beds also may have a 20-year warranty, but a significant number of these brands provide a warranty ranging from 5-15 years.
Advantage: higher density