Initially developed by NASA researchers in the 1970s, memory foam is today one of the most popular comfort layer materials on the market. Memory foam is also commonly known as ‘viscoelastic polyurethane foam’ or ‘low-resilience polyurethane foam (LRPu)’. However, it’s important to note that not all memory foam mattresses are strictly polyurethane-based (see next section for more details). In addition to mattresses, memory foam is also commonly found in pillows and mattress toppers.
Memory foam bridges the gap for mattress comfort layers. It combines the low cost and shape retention of traditional polyfoam with the superior support and body-contouring of a latex comfort layer. An important characteristic of memory foam is that it is viscoelastic, meaning that it changes shape when pressure is applied, and then returns to its original form once the pressure is released. Memory foam is also designed to respond to temperature. When you are lying on memory foam, your body heat will cause the foam to become softer, which allows the material to conform to your figure. After you get up, the memory foam will cool down and return to its original, firmer shape.
Memory foam mattresses are ideal for certain types of sleepers. Side sleepers, for instance, benefit from an exceptionally soft comfort layer because it allows their hips and shoulders to sink into the mattress properly. Side sleeping on a mattress that is too firm can lead to aches and pains caused by spinal misalignment. Memory foam can also help sleepers with chronic back or shoulder pain. The material is designed to conform to your figure and alleviate pressure points, leading to a comfortable, relatively painless night’s sleep. Additionally, memory foam is engineered for low motion transfer — and may be ideal for light sleepers who easily awaken when their partner moves or shifts positions. For those requiring a firmer feel, hybrid memory foam mattresses are constructed with a memory foam comfort layer and an innerspring support core.
Read on to learn more about memory foam. You can go directly to learn about memory foam mattresses with the highest customer satisfaction rates, or scroll down to check out our detailed consumer guide.
Types of Memory Foam Mattresses
You’ll find several varieties of memory foam mattress available on the market. Some of the most popular models include:
Traditional(or viscoelastic) memory foam is the most widely available variety of the material. It is polyurethane-based, and categorized as a type of polyfoam.
Plant-basedmemory foam is manufactured using a combination of petrochemicals and botanical ingredients. Plant-based foam layers are designed in an open-cell configuration, making them more breathable and cooler for sleeping than standard memory foams.
Gel-infusedmemory foam is a relatively new material, and is not as widely available as other memory foam types. The addition of cooling gel helps reduce heat and keep you sleeping comfortably. The shape retention of gel-infused memory foam is comparable to traditional memory foam.
Copper-infusedmemory foam, another relatively new version of the material, features beads lined with thin copper wire placed throughout the foam. Like gel, the copper components will help you sleep cooler throughout the night. This material is also designed to help sleepers with joint pain and stiffness, since copper is known to aid with blood circulation.
The Feel of Memory Foam
The popularity of memory foam is largely due to its ‘customized’ feel. Let’s explore some key qualities of memory foam mattresses:
Memory foam will contour to a sleeper’s body, resulting in a ‘just right’ feeling for most people. This ensures that individuals will receive adequate body support — no matter what type of body they have — and this can help them maintain proper spinal alignment and prevent or reduce back pain.
Because the foam compresses based on the amount of applied pressure, the material feels more responsive to your figure than other mattress types. Some have likened this responsiveness to receiving a ‘hug’ from their mattress, while others describe the feeling as ‘sinking’ into the bed.
Memory foam is one of the softest mattress materials available, which is ideal for lightweight people but may not be comfortable for people who weigh more than 230 pounds.
Density and ILD
Two important considerations regarding memory foam mattresses are density and indentationload-deflection (ILD).
Density is measured in pounds per cubic foot, and is used to indicate how well the mattress will support your body weight. Most memory foam comfort layers range in density from 2.5 pounds per cubic foot to 8 pounds per cubic foot. A common industry benchmark for a high-quality memory foam mattress is a density of 4-5 pounds per cubic foot. Density is used to categorize memory foam into three grades: low, medium and high. The table below features a detailed breakdown of memory foam density.
Density (pounds per cubic foot)
2.5 to 3.9 lbs/ft3
Retains original shape very quickly; offers good motion isolation and some contouring
4.0 to 5.9 lbs/ft3
Retains original shape somewhat slowly; offers very good motion isolation and good contouring
5.5 lbs/ft3 and higher
Retains shape very slowly; offers excellent motion isolation and contouring
While density measures the supportiveness of memory foam, ILD is used to gauge the firmness of a mattress. ILD indicates how much pressure is required to make a four-inch indentation on the top surface of a mattress. The higher the ILD number, the firmer the mattress. Some mattresses carry an ILD range, rather than a single number, because the firmness may be influenced by other factors, such as room temperature. Most memory foam mattresses on the market have a comfort layer with an ILD number that falls between 8 and 20; as a general rule, look for memory foam mattresses with an ILD of at least 10. The table below explores ILD numbers in-depth.
Most sleepers experience significant sinking
Most sleepers find this to be the ideal softness/firmness level for a memory foam mattress
Minimal sinking, and less contouring than mattresses with lower ILD ratings
Memory foam is also available in a wide range of ILD ratings. Exceptionally soft memory foam will conform to your body more easily, but may also create a ‘sinking’ feeling that some sleepers find uncomfortable. On the other hand, ultra-firm memory foam provides a more stable sleep surface but is not as effective at alleviating pressure points.
Because the material is so soft, a ‘memory foam mattress’ is not entirely made of memory foam. Rather, the comfort layer (usually 25% to 40% of the mattress) is made of memory foam, while the larger support core is constructed from a sturdier material — usually high-density polyfoam or innersprings — to prevent you from completely sinking into the mattress.
Other Important Considerations
In addition to the density, ILD number and mattress construction, there are several other factors to consider when shopping for the right memory foam mattress.
Cooling elements:Due to the contouring effects of memory foam, many people find that these mattresses sleep warm to the point of discomfort. Cooling components (like the gel and copper-infused foams mentioned above) are designed to reduce this effect — although the extent to which they reduce heat has been debated.
Thickness of the top memory foam layer: Memory foam mattresses will vary based on the thickness of the top memory foam layer. A thicker top layer may provide added support for certain sleepers, such as heavier people who feel they need extra contouring.
Mattress cover: The top cover — located above the comfort layer — will also vary in its thickness, as well as the material used to make it. Covers that are thicker or constructed from less breathable materials may cause you to sleep hot, and also may affect the responsiveness of the memory layer.
Mattress composition: Many foams are made from flame retardants and other chemicals. While these materials are generally regarded as safe, they are not necessarily eco-friendly — and you may prefer a mattress made of plant-based foam or foam certified by organizations like CertiPUR-US.
Pros and Cons of Memory Foam
Memory Foam Mattresses
Contours to the sleeper’s body for spinal support and pressure relief
Memory foam can create a ‘sinking’ feeling that some sleepers may not like
Evenly distributes the sleeper’s weight for added comfort
Poor heat retention due to lack of breathability means that the mattresses often ‘sleep hot’
Motion isolation reduces nighttime disruptions for sleepers that share a bed with someone else
Lack of responsiveness in the mattress surface can make sex less enjoyable
Mattresses are compressible, which makes shipping easier
Off-gassing smells are common with viscoelastic memory foam and other foams not made from organic materials
Memory foam has been touted for its signature hugging and contouring properties, and the material’s ability to evenly distribute weight. The result is a fit that feels customized to your specific dimensions. Memory foam also targets pressure points throughout your body. This can improve your spinal alignment and alleviate aches and pains.
Motion isolation is another perk. This term refers to the fact that pressure applied to one area of a memory foam mattress will not affect other parts. For couples, motion isolation can reduce nighttime disruptions caused when one person gets up or shifts their position in bed.
Finally, memory foam mattresses are usually compressed for shipping. This allows customers to easily order them online without the need of a truck. The foam’s full shape will begin to recover as soon as the mattress is removed from its shipping container.
While there are many benefits to using a memory foam mattress, these models also carry drawbacks for certain sleepers.
One downside to memory foam is heat retention. Many people who use memory foam mattresses complain that the mattress ‘sleeps hot’ compared to innerspring and hybrid mattresses. This is due to multiple factors. Memory foam is not very breathable, and ultrasoft foam that causes sinking can create an uncomfortably warm feeling for sleepers. The amount of heat retention in memory foam depends on its material composition, as well as the thickness of the mattress’s comfort layer.
Another common complaint about memory foam is the smell, an issue commonly referred to as off-gassing. Particles called volatile organic compounds (VOCs) are formed when memory foam is manufactured, and are released when the mattress is removed from its packaging. Although VOCs are relatively harmless, the odor may produce a strong sensory reaction. Viscoelastic memory foam mattresses — particularly those with thick comfort layers — are known to create the harshest off-gassing smells, while plant-based memory foam produces little to no off-gassing. Other mattress types, such as innerspring and latex, also produce much less off-gassing. The good news: once a memory foam mattress is unpackaged, the off-gassing smells will go away within a few days.
Additionally, memory foam is considered less than ideal for sex. Although this varies for each couple, many find that the contouring effect makes them feel like they are ‘fighting’ the bed. The lack of bounce may also be distracting.
Memory Foam Lifespan and Mattress Warranties
The lifespan of a memory foam mattress will depend largely on the foam’s density grade. Low-density memory foam will retain its shape quickly, but the material degrades at a faster rate and has the lowest amount of motion isolation. High-density memory foam, on the other hand, offers superior body-conforming and low motion transfer — although this material is slower to retain its shape after each sleep. Medium-density memory foam provides a compromise between low- and high-density foam in terms of cost, shape retention, motion isolation and other key factors.
Most memory foam mattresses are designed to last for at least five years of regular use. In order to maximize the lifespan of your memory foam mattress, you’ll need to look carefully at the material composition of the mattress — in particular, the ratio of memory foam to cheaper types of polyfoam in the comfort layer and the support core. Also take time to inspect other aspects of the mattress, such as the type of stitching found on the cover and seams.
Additionally, you should make sure your memory foam mattress comes with a robust warranty. Although the warranty length is key, you should also understand what the warranty covers. For example, the best memory foam mattress warranties should cover sagging, one of the most common issues associated with memory foam. The warranty should also discuss in clear terms how the manufacturer handles warranty claims, turnaround time, shipping costs and mattress replacement. For more information about warranties, please visit our guide to Understanding Mattress Warranties.
Average Lifespan of a Mattress
Cost of a Memory Foam Mattress
Memory foam mattresses will vary considerable when it comes to price point. Some models cost as little as $300 to $400, while high-end and luxury memory foam mattresses will cost upwards of $3,000. Foam density is one factor that affects price; low-density foam will be the cheapest, while high-density foam is usually the most expensive. Plant-based memory foam, as well as gel- and copper-infused foam, will typically cost more than standard viscoelastic memory foam mattresses.
According to our findings, youshould expect to pay between $800 and $1,000 for an excellent memory foam mattress with a favorable warranty.
How Much Should You Pay for a New, High-Quality Mattress?
According to our data, memory foam mattresses carry a customer satisfaction rating of 72%, which matches the satisfaction rating of hybrid mattresses. The average customer is happier with a memory foam mattress than with an innerspring; these models carry a 66% satisfaction rating. However, the rating for memory foam mattresses was lower than latex (80%) and airbed (78%) mattresses.
Important Questions for Consumers
When purchasing a memory foam mattress online or in a store, make sure to inquire about the following characteristics.
What is the material composition of the foam?
How thick is the comfort layer?
What are the density and firmness (ILD rating) of the foam?
How long should I expect this mattress to perform before a replacement is needed?
Will this mattress provide adequate support and comfort, given my preferred sleep position?
For couples: will this mattress be comfortable for both of us?
Is the bed constructed from materials that will produce off-gassing smells?
Is there a trial period for testing out the mattress? If yes, then what is the return policy?
How long is the mattress covered under warranty, and what are the specific coverage terms?