Definition of Bonnell Coil

Meaning of the Term as it Pertains to Mattresses

What is a Bonnell Coil?

Bonnell coils are hourglass-shaped springs that provide support in innerspring mattresses. The wide portion of the hourglass flexes easily and allows the body to sink in when weight is applied, providing responsive initial comfort. The more tightly curled center of the hourglass is less responsive and offers deep, stable support that is essential for a night of restful sleep. Coils are laced together with cross wire helicals to form a Bonnell unit, also called a single coil or uncoil system. This continuous coil arrangement provides balanced body support.

A Traditional Support System

The Bonnell coils design was originally used in buggy seats in the 19th century and was later adapted for the mattress industry. Today, it is the oldest mattress coil construction in use and is commonly found worldwide. The Bonnell coil is also the most cost-effective coil system available and can be found in most budget mattresses. Offering trusted support at a good price, Bonnell coils are popular with value seekers and regularly found in hotel and college dorm mattresses.

Coil Performance

Made from tempered steel, Bonnell coils are tough and long-lasting. Coil count and coil gauge may affect the durability and level of support a Bonnell coil offers. Generally, adults want a minimum coil count of 500. Coil gauges usually range between 13 and 16, and shoppers should note that lower numbers indicate a thicker, firmer gauge. Due to the linked arrangement of coils, the Bonnell coil is subject to transfer of motion.