Each component of your wall contributes to its overall thermal efficiency, commonly referred to as its 'U' value.

The U-VALUE (or K Value) expressed as W/m²*K is the coefficient of thermal transmittance.

This is the amount of energy passing through a material or structure in one hour expressed in watts per square metre for a temperature difference between the two surfaces of 1°C (=1°Kelvin).

Hence, the lower the U value, the better the insulation.

Provided you know the thickness (t) and thermal conductivity or Lambda () value of each component, the U value is quickly calculated using the formula:
U = 1 / (0,13 + 0,04 + ( width / ))
Please enter your data in the fields below and click on the Send Data button (the preset data is typical for a 250mm Styro Stone wall)

Please note: you can't enter 0 (Zero) for Lamdba-Value.

	Width [m]	Lambda ()
Inner Render/Plaster
Inner insulation
The wall structure (i.e.: concrete)
Exterior insulation
Exterior render

U = ?

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