Density is a measure of quality which tells you how much one cubic foot of memory foam weighs. Density is a measure of quality and not firmness. The most common density is 5 lb. memory foam and that is where the confusion begins. Tempur material was the first memory foam to come onto the market and its density is 5.3 lbs. per cubic foot. This quickly has become the standard for measuring quality in memory foam products. For a topper, 3 lb. memory foam or better will normally suffice. For a mattress, 4 lb. memory foam or better is recommended. If the density is less than 4 lbs. per cubic foot, the mattress will not last very long. You can easily expect a 4 lb. or better mattress to last you for more than 10 years. There is a new type of memory foam that weighs in at an 8 lb. density. Tempurpedic has a new mattress coming that uses a 7.2 lb. density. These super-high density memory foams are an interesting product that will create new trends in the foam bedding industry.
ILD is a measure of firmness with foam products. It can be extremely confusing to understand how the measuring process works, so I will try my best to explain it in plain english. The easiest way to understand ILD is to use a sliding scale. With memory foam products the most common ILD ratings are from 8-20. 8 is plush and 20 is firm. Tempur material has an ILD of 14 and has a medium firmness level. Memory Foam with an ILD rating of 10 is plush and supportive with a rating of 5 lb. density. ILD is the MOST important thing to consider when buying memory foam products anywhere.
Creating memory foam
Memory Foam is created in 3 main ways
1. The first way to create memory foam is with a molding process. This is the way Tempurpedic creates their memory foam. The process uses chemicals that all other memory foam manufacturer’s use, but it is honestly a subpar way to create memory foam that results in inconsistencies to the way each mattress feels. Test this for yourself and you'll find that some Tempurpedic mattresses that are the same model will feel different when tested.
2. The second way to produce memory foam is in a vacuum sealed chamber. This is the way foamex creates their memory foam and it provides a solid feel and a consistent product.
3. The last way to create memory foam products is perhaps the most disturbing. This is the way most Chinese memory foam is created. They create closed cell foam and then they crush it to create open celled memory foam. This leads to a feel that is fairly consistent and is honestly not as awful as it sounds. Chinese memory foam has improved in quality dramatically in the last few years and can be a decent value at much lower prices than some of the common brand names.
On Ebay, 85% of listings are set up by only two different companies. One company is completely dishonest about their products and the other uses their other IDs to mislead customers into seeing false competition. Be careful when buying memory foam on Ebay and don't become a victim.