In most religions, new churches, temples, or others religious facilities go through some form of consecration ceremony before they are opened.  This is done for several reasons, but one of them is to help ward off evil.  These ceremonies may not be completely successful in all cases, but they do help.  
    You can use similar measures to help keep evil out of your house.  You can say a prayer to ward off evil when you move in.  You can also place protective quartz crystals around the outside of the house, usually at each corner.  
    I remember hearing that Maya Angelou said on Oprah once that if she was entertaining guests at her house, and someone in the group stated speaking negative, bigoted, or divisive thoughts, she would politely tell that person to leave her home.  No second chance.  She didn't want people who had those kind of thoughts in her home.  She felt the negative energy of their thought would settle into the furniture and the house itself and change it.  To a large extent, I agree with that.  It's kind of the same thing that happens when a violent death occurs in a building and "ghosts" of the event are occasionally seen by visitors sometimes many years after it happens.  These are not spirits trapped in the physical world as some suggest.  It's more like a kind of 3-D movie that was recorded and stored in the building and it plays back occasionally.  Kind of like the house is having nightmares.  So you should also try to avoid having very negative, hateful people in your house.