There is often a lot of confusion about what memory foam density is and what the differences in densities mean. Take a look around at the available memory foam mattresses for sale and you'll more than likely uncover a lot of conflicting information depending on which manufacturer you listen to. So, let's take a better look at memory foam density and explain everything you need to know.
Memory Foam Density Explained
When manufacturers talk about density they are often referring to the top visco-elastic memory foam layer, rather than the entire mattress. This is because the base layer is usually a highly-resilient polyurethane foam, and the top layer is the memory foam that will ultimately be the most important for providing support and as a result will be the mostly costly to produce.
The density rating of the memory foam mattress topper or mattress is the amount of visco-elastic memory foam that is present within the foam layer of the product. A memory foam layer that has higher density will be heavier than one with lower density. The weight isn't something that means the mattress will be more or less supportive or comfortable, but what it does mean is that the air cavities and cells will be greater in number, closer together and smaller. This is what influences the extent of support the mattress will provide for the following reasons...
- The cells are more resilient to breaking down preventing the mattress from sagging over time.
- More closely knitted cells means greater skeletal and muscular support for the body.
- More cells means the mattress is likely to have a greater life expectancy, providing you restful supportive sleep for many more years.
As a comparison, less density means that there is not as much visco foam in the supportive layer, so the cells are bigger and air cavities too. As a general rule, the higher the density of the mattress' memory foam layer, the greater the support it can provide and more expensive it is to manufacture. This is why most cheap memory foam mattresses have less density (visco-elastic foam) than models from some of the best memory foam mattress brands such as Tempurpedic.
Calculating Memory Foam Density
The calculation of density rating is made by weighing a cubic meter of memory foam. The measurement is given as a weight and you will find the density provided in kilogram per cubic meter or in pounds. For instance some manufacturers will provide the rating as 85kg/m3 for example, whereas others may provide it as 5.3lb.
Some of the cheap models use as little as 40kg/m3 of memory foam, but there are mattress models that contain amounts of over double this.
Noticing the Difference of High Density Memory Foam
It can sometimes be difficult to tell the difference between memory foam mattresses by purely sitting on them for a few minutes. Higher-density memory foam mattresses will generally feel more full-bodied than lower-density mattresses, but the firmness shouldn't always be relied upon. Cheap or discount memory foam mattresses can be made to feel firm in order to make the mattress seem that it's higher density. However, because it is actually not high density, you will notice sagging and break down in a shorter period of time.
A good way of telling the true quality of a mattress is by researching what type of warranty comes with the mattress. Top brands usually provide a long and extensive warranty period as they back their product. Cheap knockoffs have minimal or no warranty in most cases.
The highest density memory foam mattresses aren't suited to everyone. Many people prefer the combination of comfort and support that some of the lesser dense mattresses provide. Obviously it's essential to avoid the mattresses on the very lower end of the density scale though for the reasons mentioned above.
As a rule of thumb, high density memory foam mattresses have a number of characteristics:
- Better durability and longevity.
- Cost more to buy in general.
- Better pressure relief, support and body contouring.
- Weigh more.
- Better motion isolation for sleeping partners.
- More comprehensive warranty.
