Mattress Coils

When considering the core of an innerspring mattress, there are a number of important factors:

1. The number of coils used throughout the mattress.

A typical mattress contains between 250 and 1,000 coil springs. A mattress with a lower coil count might use thicker wire to compensate for this.

2. The way the coils are constructed.

a. Gauge:

When discussing the coils of an innerspring mattress, the word "gauge" refers to the thickness of the wire used to construct the coil.

b. Working turns:

Another important factor is the number of "working turns" in each coil, a measurement of how tightly the coil is wound.

c. Tempering:

Tempering is the process of heating and cooling the coils to ensure they retain their proper shape over time.

3. The shape of the coils.

There are three main coil designs used in modern mattresses:

a. Hourglass.

Hourglass coils, the most commonly used design, come in two varieties — Bonnell coils and Offset coils. Today, Bonnell coils are still the most prevalent coils in the mattress industry, though they are typically found in less expensive mattresses.

b. Pocketed.

Pocketed coils, also known as Marshall coils, are each individually wrapped in a fabric pocket. On the flip side, pocketed coils endure greater strain over time, since each coil absorbs weight without distributing it to other nearby coils. Simmons uses pocketed coils in most of their innerspring mattresses.

c. Continuous.

Continuous coil designs allow for significantly more coils per mattress, making it difficult to compare coil counts with non-continuous coil systems.