A house is necessary to make a home and has been a dream of many. A home allows one to express themselves and their family as they please, without intrusion of a landlord or the public. A home is a place where one can invest themselves and create a little place where they can exclusively call their own.
To me, a house becomes a home when one expresses themselves through their house. From the little rock path you wanted science you were a child to the interiors that only scream you; a house becomes a home when one puts time into it to make their house exclusively their home.
One can make an apartment their house by placing their belongings in it, but they will eventually find a feature they can not change to their liking. For example: the color of the walls, the way the windows are paneled, and the floorplan of the house itself. A home to yourself allows one to change such things to their liking, as they please.
So, in summery, a house becomes a home when the person living in the home is allowed to freely express themselves, without filtering through landlords or other owners. Free expression of themselves.