What Is the Difference Between 3-lb. and 4-lb. Visco Memory Foam?

History

• The National Aeronautics and Space Administration, also known as NASA, required a material to protect astronauts from impact when a shuttle exited or returned to Earth's atmosphere. In 1966, NASA developed a material known as memory foam to suit that purpose.

Types

• Memory foam is available in multiple densities. According to the Memory Foam Guide, densities in the 2- to 5-pound range are most common. However, memory foam products may also have a 6- to 8-pound density.

Function

• The higher the density rating (poundage), the firmer the memory foam will be. Therefore, 4-pound memory foam is softer than 5-pound memory foam, and 2- or 3-pound memory foam will be softer still. Additionally, a higher rated density indicates that the foam will have a longer recovery time, meaning that impressions will remain in the foam longer.

Significance

• Persons who require firmer memory foam mattresses for physical health and comfort may choose 5-pound memory foam over 4-pound.

Considerations

• While a consumer may prefer a visco-elastic memory foam mattress or mattress topper that has a density rating of 5 pounds, this will cause the mattress or topper to have a greater weight than comparable 4-pound memory foam.

Warning

• Because memory foam responds to heat, manufacturers do not recommend memory foam products for persons who weight over 250 pounds. Heavier people will product more body heat that can increase the breakdown of a memory foam product.