Q. A respected lecturer advised during one of his speeches that a person should also greet with salam upon entering his home. At times, no one is present in the home. Can the greeting of salam also be made in this situation?
A. Salam is not only a phrase of greeting, but is also an invocation. Therefore, it is correct that you should greet the people of the home with salam upon entering it. If no one is present in the home, then say the words of salam in this manner:
السلام علينا و على عباد الله الصالحين
Trans: Upon us and the righteous servants of Allah be peace.
Kitab al-Fatawa, Vol. 6, p.117 (Karachi: Zam Zam Publishers, April 2008 ed.) by Mawlana Khalid Saifullah Rahmani
 Al-Fatawa al-Hindiyyah, Vol.5, p.325