Rest of the Sleep Disorders Forum Posting

Posted by Honest Expert on April 01, 2002 at 18:19:15:

In Reply to: Tempurpedic clone posted by merr on March 31, 2002 at 13:59:36:

Hi Merr,

Well, you have asked a handful of questions there!

I'll try to shed some light on your questions, even though I may not quite answer some of the more specific ones.

First off, Tempur-pedic is made of a foam commonly called "memory foam." More accurately, it is called Visco-elastic foam.

"Memory foam" comes in two distinct categories: Temperature sensitive and non-temperature sensitive. The temperature sensitive versions are somewhat more costly, unfortunately.

(But here's a warning: I have come across a brand of "memory foam" pillows that state in bold letters on ther packaging that they are "temperature sensitive." And they are! But they will not soften until they reach 140F, which, of course, is way hotter than any person should ever get! When I say "temperature sensitive," I mean it will have a significant softening effect at body temperature.)

Part of the attractiveness of Tempur-pedic (and I say this without any attempt to endorse their product!) is the definite softening at body temperature. This makes their foam have a gentler touch on the body than some others, while the density of the foam still provides good support.

So, with "memory foam," the ability to soften at body temperature -- and how much it softens -- is a very important part of the equation. Generally speaking, the lower the price of the foam, the less it will soften. (This is not exactly true, but true often enough to be a fair guideline.)

The next property to compare is density. As you have seen, some brands have a lighter density foam than others: 4.0 lbs per cubic foot vs. 5.3 lbs per cubic foot, etc.

At the International Sleep Products Association show in Denver, I had the chance to talk to half a dozen foam manufacturers about foam properties. One of the things that seemed universal amongst them was expressing the (informed) opinion that more foam density was directly related to performance and durability.

Of course, the quality of the resin used to make the foam will have a bearing on this, too, but I received an interesting response when I asked about this: I was told, "There is a limited market for the high-density/low resiliency foams. No one is going to invest the research dollars needed to make a cheap foam from cheap resins when the research is already done to make a good one from expensive resins, and the demand is still high."

From this I interpret that any foam of high density will be a pretty good product, with -- generally speaking -- the higher densities being better performing. Unfortuantely, manufacturing variables in quality control can have a great bearing on this, since consistency could be poor. When I see a less expensive foam, I wonder where the manufacturer -- either of the foam or of the mattresses -- found the savings.

A third property of foam to be aware of is ILD/IFD, which are interchangable terms for the ability of a foam to push back against force. (The letters stand for Impression Load Deflection/Impression Force Deflection, in case you were curious.)

ILD is measured by taking a disc and pressing into the foam. The more strength the foam has to push the disc back up is its ILD, which is stated as a number value. The higher the number, the stronger the push, so a 30 ILD is stronger than a 15 ILD.

ILD determines how easily a foam will shape to your body and how much support it is capable of giving. Very low ILD foams are wonderfully cushy on the body, but provide very little support.

Now, the significance of Visco-elastic foam is its ability to CHANGE ILDs at body temperature! So, when comparing "memory foams," one must understand both the ILD at cooler temperatures -- since this is where support is going to come from -- and at warmer temperatures -- since this is where the gentle touch on the body is going to come from.

I will tell you there isn't one person in a hundred who could tell you how their product compares to another in this property, including Tempur-pedic. But this is the very basis for support and comfort from a "memory foam!"

The last thing I'm going to mention (bore you with?) is mattress construction. Many of the brands making "memory foam" mattresses do not -- in my opinion -- understand the way the stuff works!

"Memory foam" feels best when it softens at body temperature. "Memory foam" supports best at higher densities. But at higher densities, "memory foam" will trap more heat, which can be very uncomfortable for some people. In fact, it is the number one complaint about "memory foam."

Many manufacturers, in an attempt to minimize their complaint levels -- especially when they are selling sight-unseen by mail order or the internet -- have started using pillowtops or heavier fiberfill padding over the "memory foam" to make it cooler to sleep on. Yet while this DOES reduce those complaints, it ALSO means the "memory foam" cannot react the best it possibly could to body temperature, because the foam is now insulated from the body!

The end result is a somewhat firmer mattress that WON'T soften to become more gentle, because the body heat cannot get to it. As a result, some companies have gone to a 2.5 lb foam to allow it to conform better to the body ... trying to recapture some of the gentleness that was lost by insulating the foam from the body heat. Of course, then they lose some support!

So, what is the bottom line in all this?

"Memory foam" mattresses that have a higher density foam will probably perform better AS LONG AS: 1) the foam is the BODY-TEMPERATURE sensitive type, and 2) the construction of the mattress has not insulated you from the foam and reduced its performance.

I believe most 4.0 lb foams are adequate for good durability, if the other components involved are also of good quality. But I think a denser foam ~may~ have some advantages ... that only YOUR BODY will define.

Then, of course, you have to love the feel of the mattress. There is no point in buying a mattress -- regardless of price -- that you don't love!

Unfortunately, I find it difficult to support online shopping for mattresses. I believe FEEL is king when it comes to mattresses, and no one can accurately convey how a mattress will feel ... TO YOU ... in an online description or a phone call. Likewise, I find it difficult to suggest shopping at a local store -- using their assets, money and time -- with the intent of buying online. It costs the store money to have the location where you can try out a product; money the online guy is not having to spend. I struggle with the idea of the retailer spending the money to help someone, only to have the online guy receive a paycheck for it. This is nothing but my own standard of ethics, mine you; just an opinion.

I hope this has been some help. Hopefully, you will be armed to do some comparing and ready to challenge a seller -- be it online or "live" -- to give you the info you need to make the best choice.

Good Luck. Feel free to ask any questions you may have. I am here to help.

Honest Expert

Follow Ups:

• Re: Tempurpedic clone liekohazel 16:59 5/14/02 (2)
  • Re: Tempurpedic clone Been There 11:45 7/01/02 (0)
  • Re: Tempurpedic clone Honest Expert 09:12 5/20/02 (0)

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