Buddy Knowledge on Innersprings
This is probably the most common material found in support cores today. These steel springs, or coils, that are evenly placed throughout the core for optimal, consistent support. Coils are usually rendered from steel and undergo tempering, which softens the metal for extra flexibility. The longevity of a coil’s springiness is known as temper memory. Coils located on the borders are often reinforced with foam, netting or other durable materials to protect against wear.
The coil count of most mattresses falls between 300 and 1,000; this amount also can be used to determine the level of support and contouring of a given mattress. Coil count is also tied to lifespan and overall cost. Mattresses with a high coil count tend to be more resilient, and thus more expensive, while those with fewer coils are usually cheaper. Though, coil count alone should not be used to judge the overall quality of a mattress.
Wire gauge and thickness
More gauge equals thinner wire. Gauge ranges from 17 to 12 and is not necessarily correlated with wire strength; wire gauge and coil count must both be taken into consideration. Additionally, the pitch, or the angle of the wire path in relation to the top surface, can be used to determine how firm the mattress will feel. And turns, or the number of times the wire is wound, will indicate how soft the coils are, and thus how supportive the mattress is.
Coil Type 1: Bonnell ($$)
Bonnell coils are straight from the in horse-drawn buggie days that feature a rounded hourglass shape; the top and bottom are threaded with corkscrew-shaped wires that join them to adjacent coils, while the sides are usually grafted to heavy-gauge wire for added stability. The result is a durable coil that won’t shift too much when compressed. These springs are mainly used in hotels, dorms and other places that serve a steady stream of sleepers over a long period of time. Bonnell spring mattresses are widely available, and most are relatively affordable compared to other innerspring.
Coil Type 2: Continuous ($$)
These are comprised of several rows, each one made up of a single wire length, and the rows are joined together by helicals on both sides. This configuration is highly stable, but its contouring abilities are minimal. As a result, continuous wire innerspring mattresses usually have a long lifespan but are considered less supportive than other models. Prices for continuous wire mattresses are comparable to the cost of a bonnell coil mattress.
Coil Type 3: Offset ($$$)
These coils also feature an hourglass shape and helical-joined configuration. However, the bottom of the offset coil is straightened; this creates a hinge-like motion when the mattress is compressed. Some innerspring mattresses feature double offset coils, which are straightened at both the top and bottom for added support.
Another variation is the free arm offset coil, which has a side or top that isn’t joined to neighboring coils. Regardless of the type of offset coil, this configuration is typically found in more expensive mattresses because the design can withstand high levels of compression for long periods of time.
Coil Type 4: Pocket ($$$)
Also known as Marshall or encased coils, are wrapped in a cloth material, forming strands of fabric used to join each individual coil. This configuration does not utilize additional wire attachments but is instead attached using hot glue. Increasing contouring and reducing motion transfer, or the amount of compression you feel when your partner gets up from or lies down on the other side of the mattress. The number of coils will range from dozens to hundreds in a single mattress. Generally speaking, pocket coil models are among the priciest mattresses on the market.
Is this right for me?
Before investing in an innerspring mattress, here are a few inquiries to make:
What type of coils are used?
- Bonnell and continuous wire coils may have a longer lifespan but offset and pocket coils are considered more comfortable and supportive and are usually more expensive.
What is the coil count?
- This number is misleading since coil count will not necessarily indicate the overall quality of the mattress; as mentioned above, you should also look at the coil shape, wire gauge, wire turns and wire pitch. But you should test out a wide range of coil counts to find the innerspring mattress that’s right for you.
Does the price match the coils?
- A mattress with a high pocketed or offset coil count will, in most cases, be much more expensive than a model with Bonnell or continuous wire coils and a relatively small count. Check to make sure the price-tag reflects the innerspring construction because this won’t always be the case.