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Originally used to pad the seats of horse-drawn carriages, innerspring cushioning was first developed for bedding by inventor Berliner Heinrich Westphal in the early 1870s. The design was revolutionary: a firm sleep surface insulated with rows of metal coils to help withstand compression and provide bodily support. The innerspring mattress was patented in the United States two decades later, and has dominated the American sales market since the 1930s. In recent years, the innerspring has competed against newer mattress types, such as polyfoam/memory foam, latex, hybrid, and airbed models. However, innerspring construction is still found in the majority of mattresses sold nationwide — roughly two-thirds of overall industry sales, according to recent estimates.
The popularity of innerspring mattresses (also known as coil mattresses) has endured for several reasons. These mattresses are the most widely available and typically the most affordable, making them relatively cheap and easy to buy compared to other mattress models. Some types of innerspring are also well-suited to certain sleepers, such as stomach sleepers, people with moderate back pain and individuals who weigh more than 250 pounds. However, several criticisms about innersprings still persist. These include premature sagging, lack of motion isolation and a short lifespan. The majority of innerspring owners have reported fair to low satisfaction levels, and these scores are significantly lower than other mattress types. As a result, innersprings have managed to become both the most popular, widely sold mattresses in the country — and the least liked.
You can jump directly to our 2017 reviews and comparisons guide to learn about innerspring mattresses with the highest customer satisfaction ratings, or read on to peruse our comprehensive innerspring guide.
The term ‘innerspring’ does not refer to the entire mattress, but rather the support core. This innermost layer of a mattress is designed to provide spinal support and pressure relief for sleepers while also withstanding compression and preventing the mattress from completely collapsing. The support core works in tandem with the topmost layer, or comfort layer, which is constructed from softer, more responsive material in order to provide a suitable sleep surface. Most innersprings have comfort layers made of polyfoam or memory foam.
An innerspring support core consists of metal springs, or coils, that are evenly spaced throughout the core to maximize support and ensure proper weight distribution. In most cases, coils are molded from tempered steel, which is considered more resilient than non-tempered steel or other metals. Coils situated at the borders of a mattress are often reinforced with foam, webbing or other sturdy materials for added longevity and performance, since the edges of innerspring mattresses are more prone to sagging than the central area.
Today’s innerspring mattresses are distinguished by the type of coils, which fall into one of four different categories.
Bonnell coils are the oldest coil type used today, and also cheaper and more widely available compared to other innersprings. Molded from tempered steel in an hourglass shape, bonnell coils are joined together with spiral-shaped wires known as helicals and often reinforced with thick, low-gauge wire. As a result, bonnells can withstand high levels of compression without shifting or falling apart. You will often find bonnell coils in mattresses used in places that accommodate a steady stream of sleepers, such as hotels, dorms and nursing homes.
Similar to bonnell coils, offset coils are made of tempered steel, shaped like hourglasses and joined together with helicals. However, the bottom of an offset coil is straightened to create a hinging effect when the mattress is compressed. Two variations of the offset coil are also common. Double offset coils are straightened at both the top and bottom for extra hinging and more support. The free arm offset coil, on the other hand, is not joined with neighboring coils. Offset, double offset and free arm offset coils are considered highly durable — and as a result, these mattresses tend to run on the expensive side.
Innersprings with continuous wire coils feature several rows of long, singular wires that are molded into circular shapes and joined by helicals on both sides. This creates a hinging motion that is similar to that of offset coils. Although noted for its stability and resilience, this arrangement cannot contour to your figure like other innerspring types. The result, in most cases, is a mattress with a long lifespan that provides minimal levels of spinal support.
Pocket or pocketed coils, also known as Marshall coils or encased coils, are wrapped in cloth, and connected to neighboring coils by strands of fabric attached with hot glue; no helicals or additional wire attachments are used. Compared to other innerspring configurations, pocket coils enhance the mattress’s contouring effects and cut down on motion transfer. Not surprisingly, these mattresses tend to be the most expensive models available. However, many pocket coils are made of thin, non-tempered steel, giving these mattresses a shorter lifespan than other innersprings.
According to our findings, innerspring owners and users have reported the following experiences:
The firmness of a mattress is somewhat linked to the gauge, or thickness, of the innerspring coils and wires. Gauge is measured in numerals that represent different widths. Most innersprings sold today range in gauge from 18 (thinnest) to 12 (thickest). The lower (thicker) the gauge of the wires and coils, the firmer the mattress will feel. You can also evaluate innerspring firmness using pitch, or the angle of the coils/wires in relation to the top surface of the mattress.
In addition to the coil type, material and gauge, coil count is another factor that may affect the way an innerspring mattress feels. The coil count of most mattresses falls between 500 and 1,000, although this number can range from 300 on the low end to more than 2,000. To a point, the coil count can be used to evaluate the contouring ability and lifespan of a mattress; models with a high coil count also tend to be the priciest, while those with low coil counts are usually the cheapest.
However, you should avoid judging the overall quality of a mattress based on coil count alone — and in some cases, the number is merely a marketing gimmick. Today’s experts note that the best innerspring mattresses on the market have a coil count ranging between 600 and 1,000 individual coils. Coil counts in excess of 1,000 are not necessarily linked to increased levels of support, comfort and mattress performance. A good rule-of-thumb when evaluating an innerspring: coil type, coil material, wire gauge and coil count, as well as the comfort layer, should all be taken into consideration.
The table below looks at coil count, wire gauge and other important factors related to the four primary innerspring mattress types.
|Coil Type||Shape||Joiner||Wire Gauge||Coil Count||Price Point|
|Bonnell||Rounded hourglass||Helicals and low-gauge wire||Low to High||300 to 600||$|
|Offset||Hourglass with straightened end(s)||Helicals||Low to medium||600 to 2,000||$$|
|Continuous||Straight line||Helicals||Medium to High||400 to 800||$|
|Pocketed||Spiral with cloth encasement||Hot-melt glue||High||800 to 1,200||$$$|
|Widely available in brick-and-mortar stores and online, allowing customers to draw from a broader selection.||Premature sagging is a common complaint with innersprings and the average lifespan is relatively short.|
|Innersprings are usually the most affordable mattress option, compared to latex, foam and airbed models.||Innersprings cannot contour to a sleeper’s body and target pressure points like latex and memory foam mattresses can.|
|Low heat retention allows sleepers to remain cool and comfortable throughout the night.||The bounciness of innerspring mattresses leaves them prone to motion transfer, which can lead to nighttime disruptions.|
|The bouncy, non-sinking surfaces of most innersprings are conducive for sex…||…but these mattresses are also noisy, and this may lead to awkward encounters.|
Innerspring mattresses are ideal for shoppers who are on a budget. With the exception of select luxury and high-end models, a new innerspring will cost a fraction of what you’ll pay for a new latex or memory foam mattress (scroll down to see our innerspring cost analysis). Widespread availability also means that you will be able to browse and test out a large selection of innersprings at any good-sized mattress store in order to find one that matches your personal preferences.
While other types of mattresses are more effective at alleviating pain and bodily pressure, some innersprings can provide adequate relief for certain sleepers. Medium-firm innersprings with resilient coils, for example, are considered the best option for people with moderate back pain. Stomach sleepers are also well-suited for medium-firm innersprings, and may find optimal comfort by sleeping with a flat pillow between the mattress surface and their stomach/hips. People who weigh 250 pounds or more may receive adequate support from firm, low-gauge innersprings.
Innersprings are considered the best mattress option in terms of heat retention. Latex and foam mattresses tend to sleep hot, which may result in sleeper discomfort and poor temperature regulation. Innersprings usually sleep much cooler because the mattress does not retain as much sleeper body heat.
Although lack of motion isolation can be a drawback (see next section), there is one notable upside to bouncy innerspring construction. Roughly 74% of innerspring owners claim that this is the best type of mattress for sex.
Innerspring mattresses have been criticized for several reasons. One common complaint is premature sagging, particularly around the edges where coils are more susceptible to indentation. Innersprings have the shortest average lifespan of any mattress type (see next section).
Another notable drawback: innersprings simply aren’t designed to contour to your figure and target pressure points in the same way as latex and memory foam mattresses. As a result, these types are considered the best options for people who require high levels of comfort and support. Innersprings — particularly those with low-gauge wire — are often criticized for being too firm.
Innersprings are also noisy and prone to motion transfer. This can mean nighttime disruptions for couples whenever one person gets up or shifts positions in bed. Additionally, some couples complain that innersprings are too loud during sex.
The lifespan of an innerspring mattress will depend on several factors. These include coil gauge and composition. Low-gauge wire is more resilient than high-gauge wire; likewise, coils made of tempered steel will have a longer lifespan than those made of non-tempered steel. For this reason, pocketed coils — made of high-gauge, non-tempered steel — have the shortest lifespan of all innerspring types. Continuous wire coils are built to withstand more compression, although they are usually made of medium- to high-gauge wire. Bonnell and offset coils, both made of tempered steel that is often low- or medium-gauge, are considered the most resilient.
That being said, our findings indicate that innerspring mattresses have an average lifespan of five and a half years, the lowest among all mattress types. Warranties are crucial for innerspring owners because they often include coverage for sagging. When a sagging claim is filed, then the manufacturer will replace the mattress free-of-charge if the indentation reaches a certain depth; otherwise, replacement expenses will fall on the mattress owner.
Warranty length is also important. Although innerspring mattresses usually last up to five and a half years, warranties may run as high as 20 years in length. The warranty will be divided into non-prorated and prorated periods; owners must pay more out-of-pocket expenses during the prorated period, which is typically the longest of the two. Also take time to learn about the manufacturer’s process for addressing warranty claims, as well as any additional fees or shipping costs for replacing a damaged mattress. Check out our guide to Understanding Mattress Warranties for more information ab this topic.
Coil type can partially determine the cost of an innerspring mattress. Pocketed coils tend to be the least expensive option; offset coils are considered mid-range; and bonnell and continuous wire coils are usually the cheapest. Regardless of coil configuration, innersprings are by and large the cheapest mattress option on the market. The cost of some premium innerspring models ranges between $1,000 to more than $2,500. On the low end, a new innerspring may cost less than $200.
Based on our findings, you can expect to find a top-quality innerspring mattress for $600. One thing to note: because innersprings cannot be compressed for shipping, online orders may include additional transport fees of up to $100.
According to our data, innerspring mattresses carry a customer satisfaction rating of 65% — the lowest of all other mattress types. By comparison, airbed (79.2%), latex (76.4%),memory foam (72.5%) and hybrid (71.0%) mattresses have all earned higher customer satisfaction ratings.
When shopping for a new innerspring mattress online or in a store, make sure to inquire about the following topics:
Although they are widely available and more affordable than other mattress models, innersprings may not be the best option for you. Be sure to check out our guides to memory foam mattresses, latex mattresses and mattress firmness for more information on choosing the right mattress.
For more information on innersprings and other mattress materials, please visit the following pages on our site:
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