Are prefabricated houses generally noisy?

Aerated concrete is actually not exactly known for good sound insulation

Multi-layered - and that's how party walls are constructed after all - the "heavy" Ytong is quite okay. But otherwise, sound insulation with Ytong is rather poor in comparison.

If it has already been perceived that way, then only sand-lime brick interior walls are possible. But be careful, these must also be decoupled from the formwork.