Coil Mattress Explained

Coil Mattress Explained

When it comes to purchasing a mattress, a very important factor to keep in mind is the type and number of coils in a particular mattress.

Mattress coils are present inside a mattress and are there to enhance the comfort of the mattress, and by extension, the quality of sleep that the user gets.

However, not many consumers are aware of what coil mattresses are and the importance they hold.

In this article, we will look into what coil mattresses are, the pros and cons of coil mattresses, different types of coil mattresses, and lots more.

If you’d like to see a graphical breakdown of the coil mattress, we got you covered:

Coil Mattress

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What Exactly Are Coil Mattresses?

springs in mattress

Coil mattresses are one of the first few modern mattresses that were introduced in the late 19th century.

They were invented by a German architect – Berliner Heinrich Westphal. The accomplished designer used metal coils that were used in the seats of horse-drawn carriages at that time.

Coil mattresses didn’t receive attention right away but eventually became popular in the 20th century thanks to the level of comfort they provide.

As the name suggests, coil mattresses are manufactured with coils inside. That’s not the only name that this mattress goes by, though. A coil mattress is known by multiple names, such as mattress springs, coil springs, innerspring, etc.

The mattress is usually designed with metal coils that are placed vertically throughout the mattress. Since the mattress is made of coils, it is known to have a springy feel.

Due to its bouncy nature, alternative names of the mattress have the word “spring” attached to them. The coils are used in the middle of the mattress to offer optimum support.

Over the years, coil mattresses have evolved considerably.

In more modern coil mattresses, tiny micro-coils are used in the top layer of the mattress, along with a coil core or other core types to elevate the level of comfort that the user feels.

Different Types of Coils Used

Coils are the basic elements of a mattress.

Since they were first developed, many varieties of them have come about. They have gone through many changes and have replaced the older and less functional ones.

Today, you’ll see that there are many different types of coils used in the design of a mattress. Here are all the types of coils discussed in detail:

1. Hourglass Coils

mattress with hourglass springs

Hourglass coils are one of the most common types of mattress coils.

They are shaped like an hourglass and come in two major types – Bonnell and Offset hourglass coils.

Bonnell Coils

Bonnell coils, as a sub-type of an hourglass coil, are characterized by an hourglass shape. They are the oldest type of springs and are used in entry-level spring mattresses.

As compared to others, Bonnell coils are the least expensive ones and also the least reliable. They have a shorter lifespan and easily suffer from wear and tear if not properly looked after.

Bonnell coils were used for the first time in the 19th century. They were used to pad carriage seats and offered great comfort and support to passengers.

Over time, the manufacturer of the coil realized that the versatile coil could be used in mattresses as well, which is how Bonnell coil mattresses came into being. 

Usually, this coil type is found in the least expensive mattresses. Bonnell coil mattresses should be used sporadically to ensure the item’s longevity. Mattresses with these coils usually last for three to five years at best.

They are a great option for mattresses that are used once in a while, such as guest room mattresses.

Not all Bonnell coil mattresses are designed the same. Different Bonnell coil mattresses use different kinds of coils and offer differing levels of comfort and support.  

Offset Hourglass Coils

bonnell springs

Offset hourglass coils are similar to Bonnell coils, but they are slightly flat on the top and bottom rather than being completely round. This change in design creates a hinging action within the core of the mattress.

This design also allows the mattress to adjust better to your body and creates less noise. The offset coils are all connected through helical – wire segments attached from top to bottom of the mattress.

This prevents the coils from moving from side to side when compressed. The offset coils are more flexible and aim to relieve pressure from the hips and shoulders.

As compared to Bonnell coils, this coil type offers better support and firmness. Offset coils are often found in slightly expensive mattresses.

They were quite a thing when they were first invented in the early 1900s by Frank Karr – the founder of the Spring Air Mattress Company. Due to this reason, offset coils are also called Karr coils.  

Offset hourglass coils come in two major types – knotted offset coils and un-knotted offset coils.

Knotted coils are more stable and smooth, while un-knotted ones are more flexible. Owing to their complex mechanisms, offset coils require high-end components, and thus, the end product is costlier than its counterpart – Bonnell coils.

2. Continuous Coils

Continuous coils also known as Mira coils

Continuous coils, also known as Mira coils, are s-shaped coils. They are made from one long piece of steel that runs from the head to the foot of the mattress.

The coil’s design is different from Bonnell coils in that they are made from different wires.

However, this set of coils is similar to offset coils, and like the latter, they are cheap too. The interlinked coil is designed in a way that helps prevent the motion of one person ruining the sleep of the other person sleeping on the same bed.

The continuous coil system is also quite durable and provides necessary support to the lower back. Mattresses made from continuous coils are suitable for people that suffer from lower back pain.

Continuous coils are more stable and durable as compared to others. Therefore, they are often the first choice for many manufacturing companies.

3. Pocketed Coils

pocketed coils

Commonly known as Marshall Coils or encased coils, pocketed coils are usually used in high-end mattresses as they are expensive to manufacture.

Due to their excellent quality and durability, these coils have become more popular over the years. Pocketed coils were invented by an English engineer – James Marshall, in 1899.

Marshall started his own company, the Marshall Mattress Company, and used these spring coils in the making of his mattresses.

Pocket coils feature springs wrapped in a fabric that allows the coil to react to the pressure separately rather than all together.

This minimizes the movement and pressure points for optimum comfort. Since the coils are encased in fabric, they are safer and longer-lasting.

Benefits of Coil Mattresses

Coil mattresses are popular for a reason.

They are one of the most common types of mattresses and boast a wide variety of benefits.

Full mattresses require a minimum of 300 coils, queen mattresses need around 400 coils, and king mattresses need approximately 480 coils.

Customers should know that mattresses with coils are pricier than the standard ones, and for good reason.

They offer a level of excellence that ordinary mattresses don’t. Continue reading this post to find out some of the benefits of coil mattresses.

1. Optimum Support

A support core layer is a layer that provides support to the mattress. It is also considered to be the core of a mattress.

The support core layers are crucial when it comes to providing sleepers with an adequate amount of support for their body.

Coil mattresses are designed from robust support layers to ensure the proper alignment of the body and spine. This makes them ideal for heavier people.

They also provide comfort to relieve pressure from the body.

Different coil mattresses support different types of support core layers. Of all of them, pocketed coil mattresses offer the best support. 

2. Offers a Lot of Comfort

comfortable coil mattress bed

Another great advantage of coil mattresses is their ability to offer optimum comfort to the sleeper.

They are shock-absorbers and aim to relieve the body of any and all pressure. They feel soft but firm.

3. Avoid Motion Transfer

Motion transfer is a huge nuisance, especially for those that share their coil mattress with someone else. This is a common problem in flexible mattresses as they jump every time someone moves.

Motion transfer is a major problem at nighttime and may disturb your sleep if the other person moves around too much in their sleep.

However, coil mattresses such as pocketed coils have the least amount of flexibility, and therefore, transfer little to no motion.

A pocketed coil mattress ensures that the movement caused by you or your partner is restricted to the coils only.

Unlike other mattresses, the movement doesn’t spread to the entire bed. This allows you and your partner to sleep more comfortably throughout the night.

4. Improved Durability

As compared to innerspring coils, encased coils are more durable and long-lasting.

Since these coils are wrapped in a protective fabric, they provide an additional layer of protection to the mattress and offer endless comfort and support to the sleeper.

Owing to the fabric around the coils, the mattress also tends to last for a long time.

5. Peaceful Sleep

Coil mattresses, especially the pocketed coil ones, allow air to flow through the bed.

This creates a cool surface that allows the sleeper to have a good night’s rest.

Cons of Coil Mattresses

1. Wear Down Faster

teared down mattress

As compared to other types of mattresses, coil mattresses tend to wear down faster.

This is especially true for hourglass coil mattresses. The excessive use of this kind of mattress spoils the coils, and they lose the ability to offer support.

That being said, many coil mattresses do not wear down as fast – pocketed coil mattresses are the best example of durable coil mattresses.

2. Heavy

Coil mattresses are entirely made from steel. Since they feature a strong metal body, they tend to be heavier than other types of mattresses.

The coils are independent of each other and therefore weigh more. Another reason that coil mattresses weigh more is because of the trapped heat, dirt, and pests.

Owing to these reasons, lifting, moving, or setting the coil mattress can be quite a chore.

3. Susceptible to Dust Mites

Coil mattresses tend to be least suitable for people who suffer from various allergies. That’s because the mattress is prone to dust mite attacks.  

These eight-legged species thrive inside the mattress because of its open-air spring system.

Dust mites lay their eggs and dispose of their feces inside the mattress, and this may cause health issues among sleepers.

People that are allergic to dust mites may experience symptoms such as itching, sneezing, red skin spots, and watery eyes. Because of this reason, people prefer foam mattresses over coil ones.

4. May Feel Warm

Coil mattresses tend to trap body heat and easily become warm.

Due to this reason, these mattresses can be a source of great discomfort in the summer season. The heat build-up makes the entire mattress hot and impossible to rest or sleep on.

However, pocketed mattresses are considered cooler than others.

The Lifetime of Coil Mattress

lifetime of coil mattress

The average lifespan of a mattress is anywhere from 7 to 10 years.

However, mattresses have a different lifespan, depending on the type. Since mattresses can be expensive to replace, buyers always aim for a mattress that lives for a long time.

When it comes to the lifespan of an innerspring mattress, it is difficult to make a comprehensive remark.

This is because the lifespan of an innerspring mattress is highly dependent on various factors – the number of springs it has, the thickness of those springs, the number of times the mattress is used, etc.

The thickness of the coil is presented in its gauge rating – ranging from 12 – 15 gauges. The thicker the coil or the lower the gauge, the long-lasting the mattress proves to be.

To ensure the longest possible lifespan, a coil mattress with a lower gauge – not more than 12 – is a good choice.

Generally, innerspring mattresses usually last for eight years. However, continuous coil ones tend to last longer as they are made from a single coil and thus are less likely to break easily.

Coil Mattress VS Other Types of Mattresses

Spring Mattresses VS Memory Foam Mattresses

comparison of spring and memory foam mattress

Memory foam mattresses are made from polyurethane foam or low-resilience polyurethane foam.

The fabric is considered to be very durable and offers a great amount of support and pressure relief – more so if it has a high density. In this aspect, memory foam mattresses are considered better than spring mattresses.

Spring mattresses begin to sag in a year or two and lose about 16% of their support. These mattresses, for this reason, fail to provide long-term support and pressure relief like memory foam mattresses can.

Since memory foams are more durable and long-lasting, they tend to be more expensive than spring mattresses.

Spring Mattresses VS Gel Memory Foam Mattresses

Gel memory foam mattresses are designed using a special technology that allows the sleeper to get a cool and comfortable night’s sleep.

Unlike coil mattresses, they do not trap body heat and keep the mattress cool all night long. In this way, you can enjoy a more peaceful and comfortable night’s sleep.

What’s better is that gel memory foams are not susceptible to dust mites or any other pesky creatures.

This reason alone makes the mattress the best choice for people with skin allergies. Gel memory foam mattresses boast a longer lifespan.

These excellent mattresses tend to outlive the spring ones as they last for around 10 – 15 years.

Spring Mattresses VS Latex Mattresses

In contrast to a spring mattress, a latex mattress has no coil or spring in it. Instead, the mattress is made entirely of a natural product that is extracted from the sap of a rubber tree.

That product is called latex. The milky sap is processed into mattress blocks, which naturally possess bounciness and offer excellent spinal support.

While spring mattresses feel firm and supportive, latex mattresses give a soft sinking feeling followed by comfortable support.

As compared to spring mattresses, latex mattresses are costlier. However, they offer comfort, firmness, and durability like no other mattress.  

Spring Mattresses VS Hybrid Mattresses

A hybrid mattress is a combination of foam and pocket springs and thus offers the best of both worlds.

It offers the additional support of the pocket coils and the pressure relief of the foam. On the other hand, spring mattresses are strictly made of coils and offer an adequate amount of support.


Spring mattresses are the oldest kinds of mattresses and have been around for centuries. Over the years, these coil mattresses have evolved and developed into many kinds.

Each coil mattress differs in terms of its properties; the most popular type of coil mattress is undoubtedly the pocketed ones.

They are considered to be the best for their ability to offer maximum support and comfort to all sorts of sleepers.

Other than coil mattresses, there are other great mattress options, too, including latex mattresses, hybrid mattresses, memory foam, and gel memory foam mattresses.

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