Dua for entering the house:

بِسْـمِ اللهِ وَلَجْنـا، وَبِسْـمِ اللهِ خَـرَجْنـا، وَعَلـى رَبِّنـا تَوَكّلْـن

Transliteration: Bismillahi walajna, wa bismillahi kharajna, wa`ala Rabbina tawakkalna

Translation: “In the Name of Allah we enter, in the Name of Allah we leave, and upon our Lord we depend”

Muslim {Hadith no. 2018) says that one should mention the Name of Allah when entering the home and when beginning to eat; and that the devil, hearing this, says: “There is no shelter for us here tonight and no food.” [Muslim & Abu Dawud]

Also see Dua for leaving the house