the disheveled or careless way way one looks, dresses, or smells, when home alone, fiddling around the house, with no witnesses;
the stereotypical way the homeless or insane asylum inmates are portrayed; completely incognizant of one's appearance, or how one appears to others;
the way one looks when he knows NO ONE (not even family, spouses, best friends, or lovers), other than a pet, will see what he looks like.
I avoid that neighbor, because he's a little house crazy!
Sweetie, it's hard for me to come home after a long day, to find you home, in rollers and old sweats, looking house crazy.