Prefabricated house vs. solid house - price difference?

Grym, this is not about the individual component wall, but about the entire building. Transmission heat loss of the building envelope

Roli: new DIN, which means it is not that new anymore. and 3/5 as a batten, without having further details, not like that for now. DDFR

Grym, this is not about the individual component wall, but about the building as a whole. Transmission heat loss of the building envelope

And who prevents one from also adhering to the other reference values for KFW55? KFW55 with a 36.5 cm wall and lambda 0.07 is definitely possible without problems. If, yes if the rest of the building is also better than the standard accordingly. A standard window has a U-value of about 1.0 to 1.2. For KFW55 a window with 0.9 is needed. Additional costs according to an internet provider: about 4 percent. It also requires a few centimeters more perimeter insulation than for a standard energy-saving ordinance house, etc...

Because aside from the fact that with 36.5 cm walls KFW55 is easily possible: The bricks are significantly more expensive than ordinary bricks with a lambda of 0.09 and therefore I almost doubt that these are really included in the standard offer.

You mean Ytong (aerated concrete) compared to other bricks (clay bricks)? As far as I know, the bricks are initially more expensive, but they can be processed much faster and easier – so you make up for a lot. My architect also has no objections to the construction method – in the city on a main road he would not build with Ytong alone, but in the countryside that should be more than sufficient.

PP 1.6-0.25 with Lambda 0.07 is considerably more expensive than PP 2-0.35 with Lambda 0.09 - that's how it was meant.

But I do have the one with Lambda 0.09 in the offer - or am I missing something here?

Then it won't work with KFW55...