There are many communities that believe that housewarming or
grah pravesh should not be performed in Ashada month. Some people even do not
shift to rented houses in Ashad Masam. There is no Hindu scripture backing for
this belief.
This taboo is not followed in neighboring Maharashtra and Gujarat during the Ashada month. Here people perform
house warming ceremonies etc.
If you look for housewarming dates in Panchang and calendars
you will not get any dates in Ashada month as most of them do not mark dates in
Ashada month.
If you want to perform puja or ceremony in Ashada month then
look for shubh dates in the month. This is marked in most calendars and use
them for your rental and housewarming purposes.
Not performing housewarming is not based on Hindu
scriptures. This is purely regional belief. Hinduism does not ask anyone to
follow any such rules.
It is for you to take an independent decision and do what is best for you. Stop discussing such things with others as there will thousands of opinion on Ashada Masam.