Which lambda value is relevant for insulation?

Hello everyone!

I have been trying to find information about the relevant Lambda values over a longer period, but unfortunately I have not been successful. I am building my house out of aerated concrete, but I do not know whether I should calculate with the thermal conductivity λ10,dry (W/mK) 0.072 or the design value of the thermal conductivity λ (W/mK) 0.08.

It is relevant from the perspective of the thickness of the exterior wall. If I calculate with the dry value, a 30cm thick wall would be sufficient (U-value = 0.230), with the design value it would be (U-value = 0.255).

Thank you very much for your time!

Regards Johann

If I remember correctly, the stone with lambda 0.08 does not exist in 30cm, but only from 36.5 upwards.

For the Gebäudeenergiegesetz / KfW / Wärmeschutznachweis / Energieausweis ALWAYS use the design value. The nominal value is only EU stuff and is not considered in German legislation.

If I remember correctly, the stone with lambda 0.08 does not exist in 30cm, but only from 36.5cm upwards.

Not with Ytong, but with bauroc it does. It costs 5 times less than with Ytong.

For the Building Energy Act / KfW / thermal insulation certification / energy performance certificate ALWAYS use the design value. The nominal value is only EU stuff and is not considered in German legislation.

Thank you very much for the clarification. I’m already embarrassed, I’ve been dealing with this topic for more than 3 years but never found anything about it.