Glossary
Breathability
How easily air and moisture pass through a fabric or mattress layer, a key factor in whether bedding sleeps cool or traps heat.
Breathability describes how freely air moves through the weave or structure of a material. A breathable fabric lets warm, humid air escape from around the body instead of holding it against the skin, which is why it matters more for comfort than softness or thread count alone.
Weave and fiber determine most of the difference. Loosely woven natural fibers like percale cotton and linen breathe well because air can pass between the threads, while dense synthetic weaves or thick foam layers tend to insulate. Mattresses and pillows work the same way: open-cell foam and coil layers breathe better than solid memory foam.
A common confusion is treating breathability and moisture wicking as the same thing. A fabric can breathe well but still feel damp if it does not move sweat away from skin, and vice versa. When shopping, look for both properties described separately, and be wary of marketing that calls something cooling without explaining whether it is airflow, wicking, or just a cool initial touch.