{[top") ?> {[text|Technical Terms| Thermal conductivity () or Lambda value expressend in W/mK.
is the heat flow in Watts/m² for a temperature gradient of 1K per metre thickness.
The lower the value, the better the insulation.
Thermal resistance (R) expressed in m²K/W is the measure of resistance to the passage of heat for a given thickness t.
R = t/
The higher the R value, the better the insulation
U value (or K value) expressed as W/m²K is the coefficient of thermal transmittance and is the reciprocal thermal resistance R so: U = 1/R
This is the amount of energy passing through a material or structure in one hour expressed in Watts per Metre² for a temperature difference between the two surfaces of 1C (=1 Kelvin).
Hence, the lower the U value, the better the insulation.
The U value of a system or structure is the reciprocal of the total thermal resistance value of each component element of the structure: i.e. U = 1/R1 + R2 + R3 ... etc.
) or Lambda value expressend in W/mK.