Dua- Entering or leaving house

Dua- What to say when entering the house

Bismillaahi walajnee wa Bismillaahi kharajnaa, wa'alaa Rabbinaa tawakkalnaa.
In the Name of Allah we enter, in the Name of Allah we leave, and upon our lord we depend [Then say As-Salaamu 'Alaykum to those present]
Reference Abu Dawud 4/325. Muslim (Hadith no.2018) says that one should mention the Name of Allah when entering the home and when begining to eat; and that the devil, hearing this says: "There is no shelter for us here tonight and no food."

Dua-When leaving the house:

Bismillaahi, tawakkaltu 'alallaahi wa laa hawla wa laa quwwata 'illaa billaah.
In the name of Allah, there is no might and no power except by Allah.
Reference: Abu Dawud 4/325, At-Tirmithi 5/490. See also Al-Albani, Sahih At-Tirmithi 3/151.

Allaahumma 'innee 'a' oothu bika 'an 'adhilla 'aw 'udhalla, 'aw 'azilla 'aw 'uzalla, 'aw 'adhlima, 'aw 'udhlama, 'aw 'ajhala 'aw yujhala alayya
O Allah, I seek refuge in You lest I misguide others, or I am misguided by others, lest I cause others to err or I am caused to err, lest I abuse others or be abused, and lest I behave foolishly or meet with the foolishness of others.
Reference: Abu Dawud, Ibn Majah, An-Nasa'i, At-Tirmithi. See also Al-Albani, Sahih At-Tirmithi 3/152 and Sahih Ibn Majah 2/336.