Differences in Memory Foam Toppers

Density

• The density of a memory foam topper indicates the topper's performance perhaps more than any other aspect. Measured in pounds per cubic feet, memory foam densities range from a 1.5-lb. density to an 8-lb. density. A higher density memory foam topper (5 lbs. and up) supplies greater pressure relief, support and memory and is more durable than less dense models. Higher density toppers, however, are also inclined to run hotter, feel stiff and cost more. Conversely, toppers with less than a 3-lb. density provide insufficient support and memory. Most people prefer 3- to 5-lb. density memory foam.

Firmness

• The indentation load deflection (ILD) reflects the firmness level, or the springiness, of a memory foam topper. ILD is calculated by dividing the topper's weight by the foam compression percentage. While the ILDs of available toppers range from eight to 20, most people find an ILD between 12 (medium soft) and 15 (medium hard) to be optimal. ILDs below 10 tend to be too soft to be supportive, while ILDs of 16 and up are considered too hard. Note that room temperature often affects a topper's ILD.

Thickness

• Memory foam toppers come in several thicknesses which typically range from 1 inch to 4 inches, with 2-inch to 4-inch being preferred the most. When evaluating topper thicknesses, consider how much cushioning your particular body needs. A heavier person runs the risk of sinking through a thinner topper, while a thick topper might not adequately support a petite person.

  Sleep style is another important aspect in choosing topper thickness, as side sleepers frequently prefer thicker toppers than back and stomach sleepers. Finally, remember that the additional height of a topper may necessitate extra deep sheets.

Composition

• Not all toppers are composed of pure polyurethane memory foam; some manufacturers add fillers. Generally, such added materials cause the memory foam to break down faster and result in hotter sleep. Added materials may also reduce the topper's responsiveness to body temperature, particularly if the topper includes a quilted microfiber cover, which further buffers the body from the memory foam. However, the addition of latex to a memory foam topper may increase support. Some toppers also feature gel beads to promote cool sleep.

Other Design Attributes

• Many memory foam manufacturers address the material's shortcomings by implementing design attributes and technologies into their toppers. To increase airflow and promote a cooler sleep surface, some toppers feature ventilation channels or special open-cell technology. Textured patterns adorn some toppers' surfaces to enhance pressure point relief and evenly distribute weight. For germ protection, different anti-microbial treatments are applied to toppers. Finally, some newer products attempt to soften the strong, chemical-like odor that typically accompanies memory foam with green tea and other natural, fresh-smelling additives.