What is "thermal resistance"

Thermal resistance is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow. Thermal resistance is the reciprocal of thermal conductance.

• (Absolute) thermal resistance R in K/W is a property of a particular component. For example, a characteristic of a heat sink.
• Specific thermal resistance or specific thermal resistivity R in (K·m)/W is a material constant.
• Thermal insulance has the units (mK)/W in SI units or ( ft· °F· hr)/ Btu in imperial units. It is the thermal resistance of unit area of a material. In terms of insulation, it is measured by the R-value.