Click on the drawing below to show the 1D cross-section on the right for the selected location.
layer properties
Dicke mm
% of timber %
Width mm
Distance ▾ mm
λ: W/mK
ρ: kg/m³
c: J/(kg*K)
ε: [0,01 - 0,99]
°C   % Humidity   Rsi...
°C   % Humidity   Rse...
Select material
All building component types WallRoofdormerFlat roofUpper floor ceilingFloorBasement ceilingHistorical timber
Color codeIso lines
Direct contact to outside airRear ventilated claddingRear ventilated roofingNon-heated roomUnheated roof spaceHeated roomGround
insert internal layer: insert external layer: Place studs or rafters in this layer Duplicate layer Delete layer
rotate layer by 90 degrees Upside down Chose thickness automatically
sloped insulation... heating level... View...
show the specs of the building material Edit layer properties...
Reduced air circulation
Furniture, decoration, corners, niches etc. hinder the air exchange on the inside of the building component. Most unfavourable case for panel heating and for moisture protection (corresponds to DIN 4108-3).
Free air circulation
Air can flow unhindered along the inside of the building component. Best case for heat dissipation of panel heating and for moisture protection.
Distance Axial dist.
Comparison with limit values of:No comparison with limit values
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Quick Start Guide

This U-value calculator analyzes your component (for example, wall, roof, ceiling, etc.) with regard to insulation, moisture protection and heat protection:

  1. Choose a material from the left panel and place it on the drawing surface.
  2. Lay all layers together
  3. Lastly insert wooden beams into the insulation layer.
Examples: Wall   Roof   Ceiling

The main results are displayed at the bottom of the screen. More detailed information can be found on the left-hand side of the screen using the buttons U-value, humidity, heat, etc.

For commercial usage, calculations are made according to DIN EN ISO 6946 (U value), DIN 4108-3 (moisture protection) and DIN 68800-2 (drying reserve).

Notes on Planning

Moist and moldy walls are the nightmare of many builders. Therefore, the U-value calculator examines your insulation for potential moisture problems. The article Wasserdampfdiffusion und feuchte Wände (in German) explains how moisture and mold can occur. At this point, the following simplification is sufficient:

In winter the warm room air contains more moisture than the cold outside air. This is why water vapor diffuses through the component from the inside to the outside. Because the outer, colder layers can only contain very little water vapor, it must be ensured that the water vapor escapes as easily as possible from the outside. If the water vapor accumulates on a cold layer, condensation is likely to occur.

Moisture protection in wood structures is particularly important. For this reason, in addition to moisture protection according to DIN 4108-3 (in German), a drying reserve in accordance with DIN 68800-2 (in German) is required, which should also allow harmless drying of unintentionally penetrated moisture.

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