Related terms
Thermal Resistivity
Thermal Resistivity is the reciprocal of Thermal Conductivity
and has units K. m. W-1.
Thermal Resistance (R)
The Thermal Resistance is the ability of a substance to prevent heat transfer. Thermal Resistance is the reciprocal of Thermal Conductance and is used when discussing the effective thermal performance of a system. Because R is dependent on panel thickness, it can be simply increased by increasing the insulation thickness.
Units m2. K. W-1.
For multiple layers of materials in intimate contact Rtot = R1 + R2 + R3 etc.
Thermal Conductance
The Thermal Conductance is the reciprocal of Thermal Resistance and is defined as the quantity of heat that passes in unit time through a section of particular area and thickness when the opposite faces have a temperature difference of 1K.
Thermal Transmittance (U)
The U value of a specified material is a term used in buildings construction whose units are the same as Thermal Conductance, W. K-1. m-2. It is defined as the air to air transmittance of an element of construction.
For multiple layers of materials in intimate contact
