It is a very important sunnah to say "Bismillah" when entering the house, & to remember Allah (SubhanaHu Wa Ta'ala) a great deal, and give the greeting of salaam, whether there are any humans in the house or not.
“But when you enter houses, give greetings of peace upon each other - a greeting from Allah, blessed and good”
[Surah an-Noor 24:61].
This was quoted from the book of Imam An-Nawawee (RH)' al-Adhkaar', page 23.
“When a man enters his house, and mentions Allah when he enters and when he eats, the Shaytaan says:
But if a man enters his house & does not mention Allah when he enters, the Shaytaan says, "You have found a place to stay." And if he does not mention Allah when he eats, he says: ‘You have found a place to stay & dinner.’
(Muslim 2018).
Imam Abu Dawood (5096) narrated that Abu Maalik al-Ash’ari (RA) said: The Prophet (peace and blessings of Allaah be upon him) said:
"Allaahumma inni as’aluka khayr al-mawlaj wa khayr al-makhraj. Bismillaah walajna wa Bismillaah kharajna wa ‘ala Allaahi rabbina tawakalna."
Classed as saheeh by al-Albaani (RH) in al-Saheehah, 225.
“When you enter an uninhabited house, say “Al-salaamu ‘alayna wa ‘ala ‘ibaad-Illaah il-saaliheen
(Meaning: peace be upon us and upon the righteous slaves of Allaah).”