Innerspring

Innerspring construction is the original mattress format — a steel coil grid topped with cotton, foam, or fiber comfort padding. Until the 1990s, virtually every mattress sold in the U.S. was an innerspring; today, traditional innersprings represent under 15% of the market vs hybrids and all-foam.

Three coil types: Bonnell coils (interconnected hourglass-shaped coils, oldest design, cheapest, transmits motion across the surface), continuous coils (single zigzag wire forming the entire grid, durable but transmits motion), and offset coils (hourglass coils with squared-off tops, slightly better motion isolation).

Modern 'innerspring' mattresses sold today (Saatva Classic, Stearns & Foster Estate, Sealy Posturepedic) typically use coil-on-coil construction — a Bonnell or offset coil base topped with a pocketed coil layer for combined durability and contouring. Effectively a hybrid by another name.

True traditional innerspring mattresses (Bonnell coils + thin foam/fiber padding only) are now mostly entry-level at major retailers. Performance is generally inferior to hybrids in motion isolation and pressure relief, though they remain affordable, breathable, and durable.

Traditional innersprings — Bonnell, offset and continuous-coil units — are now a minority of the market, but they remain the most breathable support system available. Air moves freely through an open coil unit in a way it simply cannot through a solid foam core, which is why the coolest-sleeping beds we test are almost always coil-based.

Where they lose to hybrids is contouring and motion transfer. Connected coils share load, so pressing down in one spot lifts the surrounding area, and every movement propagates across the bed. If you sleep alone, sleep hot and want a bouncy, on-top-of-the-bed feel at a low price, a quality innerspring is still a rational buy.