Textile Glossary

Thermal retention capacity

Definition

Thermal retention capacity describes the ability of a textile to retain the heat emitted by the human body within the air layer between the skin and the fabric, and to slow the dissipation of heat to the surrounding environment. It is a function of the thermal conductivity of the fiber material, the fabric structure, and the volume of entrapped still air, since air is a poor conductor of heat. A high thermal retention capacity means that the textile effectively insulates body heat and thereby supports thermal comfort under cool ambient conditions. This property is commonly characterized by the thermal resistance (Rct) and depends on factors such as fabric weight, thickness, and the proportion of fiber void space.

Use in the textile industry

In the textile industry, thermal retention capacity is a key selection criterion above all for functional and protective clothing, winter outdoor textiles, and occupational protective garments for cold environments. Fibers with a naturally high pore fraction, such as wool, and synthetic hollow fibers are specifically used to achieve high thermal retention capacity at the lowest possible weight. Fleece and nonwoven structures, as well as multilayer systems, also exploit the principle of entrapped still air to increase the insulating effect of the textile.

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Frequently asked question

Both terms describe the insulating effect of a textile and are often used interchangeably; however, they emphasize slightly different aspects. Thermal retention capacity stresses the active ability of the material to retain body heat within the clothing layer, whereas thermal insulation capacity refers to the resistance of the textile to heat transfer from one side to the other. In measurement practice, both properties are captured through thermal resistance (Rct), so the distinction is primarily conceptual in nature.

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