Is there a special Dua to recite when occupying a new house?

Answer

There is no special Surah/Dua to recite when taking occupation of a new house. Recite the usual Masnoon Dua when entering the apartment. You could perform two raka'ts Salaat there and make dua for aafiyah and for protection against the evil of the house. Rasulullah (sallallahu alayhi wasallam) had mentioned that there can be evil in a house.