There is this cool concept called Bio-Biologie, formed by a German guy called Dr. Anton Schnieder, which looks at the house and its surroundings as a biological entity, almost as if it were alive.
And like any living entity it needs certain things to remain healthy, which in turn keeps the inhabitants healthy. Many houses don’t have these aspects.
These are simple things like non toxic materials, plenty of sun and air, no radiation or electromagnetic fields and lots of green. Basically they are feel good things and are very useful whenever doing a remodel or new building.
This site outlines 25 of his most important points.