Calculation of U-value

With the help of our database, you can easily perform a calculation of heat transmission coefficient online. To do so, insert the desired layers from the database below by clicking on the respective layer. The calculation is done according to DIN 4108.

What is the U-value?

The U-value is the heat transmission coefficient (formerly also called k-value). It belongs to the specific characteristics of building components and includes the insulating effect or the insulating properties of building components. The U-value indicates how high the heat loss through a component or a multi-layer material layer is. It is specified in the unit W/(m2K). The U-value quantifies the amount of energy that flows through an area of one square meter when the air temperature on one side of the component or material layer is one Kelvin lower than on the other.
The aim is to achieve the lowest possible U-value, because the insulation effect will be that much better.

KfW requirements for the U-value

The Reconstruction Loan Corporation (KfW) prescribes minimum requirements for the U-values of building components for the promotion of measures for energy-efficient renovation: