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The Ultimate Mattress Coil Guide: Everything You Need to Know About Coil Types, Coil Count, and Coil

An innerspring mattress has been around since the 19th century and is still the most popular type of mattress today. In fact, about 80% of homes in the US have some model of an innerspring bed.

Innerspring mattresses use metal coils as a support system. They provide a unique bouncy feeling that offers support and comfort to sleepers of all shapes and sizes.

Luckily, today’s innerspring mattresses evolved to provide superior comfort and durability. That’s why we want to discuss the factors that affect the quality of your innerspring mattress. So, let’s go over coil types, coil count, and coil gauge and see why they are important.

Why Are Mattress Coils Important?

Mattress coils are made of metal and form a core of an innerspring mattress. They are designed to support your body while sleeping by flexing in response to pressure. When you get up, the metal coils spring back to their original position.

The great thing about these coils is that they can support sleepers of all sizes. In fact, the more pressure you put on them, the firmer support they provide. That’s why many hybrid mattresses use coil systems for the strong core layer.

Most mattress coils are made of steel that undergoes a treatment called tempering. This process improves the toughness and durability of steel, ensuring that the springs retain their shape for years.

Mattress coils are great because they are cost-effective and durable. This makes innerspring models affordable, which is why so many people choose them. In addition, coil-based mattresses are light, breathable, bouncy, comfortable, and durable.

However, coil types, gauge, and coil count play a vital role in the quality of these mattresses. Let’s see how.

Different Mattress Coil Types

There are four major types of coils used in mattresses. Each one has different characteristics, affecting the overall quality and comfort of a mattress. It’s also important to mention that there are variations of these types of coils. So, manufacturers may use different designs or materials when creating their mattresses.

Bonnell Coils

Bonnell or open coils are the basic type of coils that have been around for the longest. They are shaped like an hourglass to provide good support for sleepers of all sizes. The thinner portion of the hourglass responds to minimal pressure, while the thicker upper and bottom parts are there for heavier support.

Bonnell coils are typically wired together to make them more durable. Because of that, these mattresses don’t have good motion transfer control. So, if you share a bed with a partner, you’re most likely to feel when they switch their sleeping position. Not to mention how squeaky Bonnell coils can get with frequent use.

Mattresses with Bonnell coils are not as durable as other innerspring models. That’s why they are best suited for kids who outgrow their beds in a few years or for guest rooms, where they won’t be used every day.

The main advantage of mattresses with Bonnell coils is that they are affordable.

Offset Coils

Offset coils have an hourglass shape similar to Bonnell coils. However, their bases are square-shaped and have a hinged design that allows them to provide better support. So, even though offset coils are also interconnected, they can flex more independently, which enables them to contour to the sleeper’s body shape.

Thanks to the hinged design of offset coils, mattresses with this support system are better at preventing motion transfer. In addition, they provide superior support and reduce pressure points. That’s why these coils are typically better for everyday use compared to Bonnell coils.

Continuous Wire Coils

Continuous wire coils are made from a single piece of wire formed into a helical shape. The wire is then woven in a pattern to create a series of interlocking spirals that run the length of the mattress.

Because continuous wire coils are interconnected, they provide a stronger, more durable sleeping surface. However, these coils don’t offer good motion isolation, and the mattresses are often noisy. That’s why they may not be ideal for couples who tend to sleep lightly.

On the other hand, mattresses with continuous wire coils are affordable, durable, and offer good support.

Pocket Coils

Pocket coils, also known as Marshall coils, are made from independent steel springs encased in fabric pockets. This design allows coils to move separately from one another. They only flex when the pressure is applied directly to them, which ensures better contouring abilities of pocket coil mattresses.

Better contouring can reduce pressure points and improve spinal alignment during the night. That’s why pocket coil mattresses are a popular choice for people with back pain or discomfort.

Pocket coils also fix the number one problem of all innerspring mattresses – poor motion isolation. That’s because the individual coils can absorb and isolate movement, which reduces the motion transfer between the two sides of the bed. As a result, this coil type is popular among couples.

Does Mattress Coil Count Matter?

Yes, coil count can be a significant factor in determining the overall support and comfort of a mattress. Coil count refers to the number of coils used, and a higher number typically means a more durable and supportive mattress. However, that isn’t always the case.

For example, Bonnell and offset coils are typically larger, so they usually have a lower count. The number can vary by a lot, but the general reference is that a full-size mattress should have at least 300, a queen should have at least 400, and a king mattress should have at least 480 coils.

Keep in mind that coil count isn’t the only thing that determines how supportive or comfortable a mattress feels. The type of coil, gauge, and other factors also play an important role.

What’s a Mattress Coil Gauge?

The coil gauge refers to the thickness of the wire used to create the core of an innerspring or hybrid mattress. The bigger the number, the thinner the wire used. So, for example, a 12-gauge wire is thicker than a 14-gauge wire.

The coil gauge affects the overall firmness and support of a mattress. In general, a coil gauge between 13 and 15 is suitable for most sleepers, offering a great balance of support, comfort, and durability. However, if you like a firm sleeping surface or are on the heavier side, aim for thicker coils and a lower number.

What Type of Coils Is Best in a Mattress?

At the, we believe that pocket coils provide the most benefits, which is why we use them in our custom mattresses. Pocket coils offer excellent support and pressure point relief, which makes them a perfect choice for most sleepers.

Pocket coil mattresses are breathable and better at isolating motion than other innerspring mattresses. That’s why couples often use them for co-sleeping. In addition, pocket coils are more durable than other innerspring models.

Check out our custom-size mattresses page, where you can order a fully personalized mattress with a pocket coil core.


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