Lifespan of memory foam and base layer of polyfoam

I believe I have read one thread where Phoenix was touting SelectFoam over Novosbed (in the battle between good and good), with one of the reasons being SelectFoam uses a higher quality base (support) layer of polyurethane foam. I think the numbers given were SelectFoam at 2.5lbs/cubic ft vs Novosbed at 2.0lbs/cubic ft.

Does this really make absolute difference in terms of lifespan of the bed (or in any other area)?. I seem to remember another thread where it was stated that anything over a 2 lb density in the base layer was good.

Also I have read that the average lifespan of medium to high quality memory foam mattress seems to be 7-11 years (which is also kind of amusing since I always hear people planning on having their bed for the next 20-25 years). Would it be fair to say that a reasonable estimated use I will get out of a Novosbed or Selectfoam (having maybe a 4 inch total memory foam layers) would be somewhere in this 7-11 year range?

I know Phoenix would say that everybody is different and what may be still in the acceptable range for one person over time might not be acceptable for another, but it would be helpful to get a general idea of how long I can reasonably expect to use the bed that I am spending money on, so I can make an educated decision based upon the value.

In other words, there is no point in paying double the amount of money if two mattresses are similar in comfort and similar in expected lifespan. Does 2.5 density vs 2.0 equate to something tangible…

Hi bmbsqd,

You can read about the many factors that are involved in the durability of a mattress (one of which is foam density) in post #4 here.

The comfort layers are typically the “weak link” of a mattress because they are subject to much more of the compression forces of sleeping and the quality of the comfort layers is a much bigger factor in the durability of a mattress than the base layers.

This would also depend on the weight of the person and the thickness of the comfort layers and how much you “go through” them into the base layers below.

In most cases … the useable lifespan of a mattress for most people will be much more dependent on the comfort layers than on the base layers.


Hi bmbsqd,

The support layers in our mattresses are 2lb, which is structurally very sound.

I fully agree with Phoenix that density in the comfort layer is much more important as long as the support foam exceeds a certain minimum quality (in our experience, anything above 1.8lb foam is sufficient).

An important point is that increasing density in a support layer is far cheaper than increasing it in a comfort layer: standard poly-foam is much less expensive than the memory/gel foams used in the comfort layers. Some companies tout this higher-density support as an effective substitute for a lower-quality comfort layer. Typically these companies offer shorter warranties.

All the best in your mattress search!