What’s the difference between Latex and Memory Foam?

They’re both fancy, foamy, and generally expensive, but what’s the difference between the two?

By sight, latex mattress and memory foam mattresses look very similar. Once you lie down on them, however, you’ll notice some big differences that will greatly affect the quality of your sleep.

Physics Mini-Lesson

Memory foam is a visco-elastic material, meaning that it has a bit of bounce, and a bit of flow. When it is compressed, it deforms, and then gradually “flows” back to its original shape. The warmer it is, the less elastic, and more fluid-like it becomes. Because it behaves a little like a fluid, it will “flow” away from heavy contours, and into lighter ones – that’s why it’s ideal for use in applications where distributed, even force is required over uneven objects (like your body).

Latex foam is purely elastic. In fact, if you drop a piece of latex foam on the floor, it bounces exactly like a rubber bouncing ball (latex is a type of rubber). Because it has no viscous properties, it doesn’t “flow” around uneven surfaces, and therefore provides uneven force against uneven objects (like your body).

Latex is also a closed-cell (tiny, sealed air-filled cells) material that doesn’t naturally breath. That’s good for some applications, but is a major challenge for its use in sleep surfaces. In the above picture, you can see the breathing holes in a high-end latex mattress. Even with these holes, which not all latex mattresses have, latex is known for being hot.

Memory foam, like all urethane-based mattress foams, is open-cell (tiny air-filled cells, each with small holes). It is a naturally breathable material.

So what does all this mean for you?

How They Feel

When you lie on a memory foam mattress, your heavier parts will displace more of the foam than your lighters parts. The foam will almost “flow” around you, filling the contours of your body. Because of its visco-elastic properties, the pressure on all parts of your body will remain the the same.

When you lie on a latex foam mattress, the heavier parts of your body will displace foam, taking with it the foam under the lighter parts of your body. The pressure on your body will be uneven, and very similar in feel to a $300 spring-based mattress. Dissimilar to a spring mattress, however, your body heat will be reflected back at you, making your sleeps uncomfortably warm in most cases.

What Makes Them So Different?

Memory foam is made by combining materials that expand to form an inert, open-cell polyurethane foam (read more about how memory foam is made).

Most people think that latex mattresses are made using natural materials derived from rubber trees, but in reality, the majority are made from industrial chemicals to make production cheaper. In fact, for a short period during the 1960’s, latex mattresses were very popular since they were believed to contain natural ingredients. They quickly went out of style when people discovered that they were, in fact, bad for the environment and that they’re generally uncomfortable.

Both memory foam and latex foam are hypo-allergenic and anti-microbial, which is a great solution for people with strong allergies. Bed bugs and dust mites have a hard time living in both types of mattresses, which is assuring whether you have allergies or not.

High-end memory foam and latex mattresses both use a supportive base layer typically made from a high density polyurethane foam.

The Verdict

Memory foam mattresses have been gaining in popularity since the day they first hit the market in the early 1990s. That’s a two-decade track record of increased acceptance and recognition with no sign of slowing in sight. Memory foam was a fundamental step in mattress technology, and has given millions of people a better night’s sleep.

Latex mattresses go in and out of style every few years, and don’t offer a fundamental improvement over existing technologies.