Innerspring mattress

An innerspring mattress, also known as a Bonnell mattress, is the predecessor of the pocket spring mattress. It consists of springs that are interconnected, unlike a pocket spring mattress where each spring is encased individually. The functioning of an innerspring mattress is simple: the more pressure applied to a spring, the more resistance it provides.

The steel springs generally have five coils. The Bonnell or biconic spring has wider circles at both ends and a narrower middle (hourglass shape). This results in progressive resistance as the load increases, the resistance of the spring increases as well. These springs are stiffer than pocket springs. The springs provide the mattress with stable resilience, and they can vary in wire thickness and the number of coils, affecting how firm or flexible the mattress feels.

In fact, an innerspring mattress is typically hard, heavy, and bulky. Unlike a pocket spring mattress, an innerspring model does not have zoned support areas. When sleeping on your side, it offers limited adaptability to the shoulders and hips. Overall, the conformity of an innerspring mattress is considered moderate.

Due to its stiffness, an innerspring mattress is generally not suitable for adjustable bed bases. While it does offer excellent ventilation properties, so does a pocket spring mattress.

As you’ve likely gathered, a pocket spring mattress provides far more comfort and support than an innerspring mattress. If you're looking for a firm mattress with metal springs, we recommend choosing a pocket spring mattress instead  which can also be delivered in a firm version.