Testing & Quality Control

Thermal Resistance TOG & Clo Value Predictor

Insulation is trapped air, so thickness dominates. Fibre type matters far less than loft.

Fabric Under standard pressure
mm
W/mK

Thermal Resistance

— TOG

One TOG is 0.1 square metre kelvin per watt

Equivalent Scales

Clo Value
— clo
Thermal Resistance
— m2K/W
Imperial R-Value
— R
Insulation per Millimetre
— TOG/mm

Conductivity here is the effective value for the fabric and its trapped air, not the fibre polymer. Measure it on a guarded hotplate rather than looking up the fibre.

Thermal Resistance TOG & Clo Value Predictor — free, with the formula and a worked example, at Textile School.