TOG

CLO was developed in 1941 to define the thermal performance of insulation. With the help of CLO, it is possible to calculate how much insulation is needed at a certain temperature to keep a person warm. The CLO was originally defined as the amount of clothing a person at rest needs to feel comfortable at a room temperature of 21 degrees Celsius. This corresponds approximately to a business suit worn by a man (shirt, undershirt, trousers and jacket). This means that the higher the CLO value of a material, the higher its insulating effect. The CLO value can be added up by adding several layers. For example, a man wearing two business suits on top of each other would achieve a CLO value of 2.

TOG

The TOG value was developed in 1960 to define insulation values. In the TOG test, a test sample (fabric or insulation) is placed on a heated plate in a device called a tog meter. Thermometers are used to measure the temperature on both sides of the test sample. After about three hours, the heat transfer resistance is calculated from the surface of the plate and the temperature difference between the inner and outer surfaces. The result is given in m2 K/W. For easier understanding, the value is often given in TOG (m2 K/W multiplied by 10).

1 Tog = 0.1 m2 K/W = 0.645 Clo
1 Clo = 0.155 m2 K/W = 1.550 Tog

To facilitate comparison, the Department of Performance Textiles at Leeds University has compiled the following table: