innerspring

An innerspring is a type of mattress support system that uses metal coils as its core. The coils are typically surrounded by padding, foam, or latex to form a complete mattress. Innerspring designs are among the most common and are offered in a wide range of firmness and support options.

Construction and coil types: The core consists of metal springs arranged in different designs. Bonnell coils are interlinked, hourglass-shaped springs commonly used in traditional models. Offset coils are similar but slightly offset to improve contour and durability. Pocket coils, or individually wrapped springs, are enclosed in fabric pockets and can move independently, reducing motion transfer. Edge support is often enhanced with reinforced coil rows or foam encasements.

History and evolution: Innerspring systems became popular in the early to mid-20th century and largely displaced earlier solid or mixed constructions. The Bonnell design and later offset variants were widely used, while pocketed coil technology emerged to improve conforming and minimize partner disturbance. Modern innersprings frequently use zoned or layered configurations and may be paired with various comfort foams.

Variations and hybrids: Many innerspring mattresses incorporate multiple coil zones for different areas of the body, along with memory foam, latex, or high-density polyfoam comfort layers. Hybrid models combine an innerspring core with a thicker foam or latex top layer.

Advantages and limitations: Innerspring mattresses are typically durable, breathable, and cost-effective relative to all-foam options. They can offer strong support and a wide range of firmness. Limitations can include greater motion transfer in non-pocket designs and potential sagging in lower-quality constructions without adequate coil counts or padding.