What is the fear of going to the upper level of a home alone called?

The fear of going to the upper level of a home alone is known as "stair phobia" or "acrophobia" if it specifically pertains to a fear of heights. While there isn't a specific term solely for being alone on upper floors, these fears can be associated with anxiety about being isolated or vulnerable. In psychological terms, it may also relate to a broader fear of abandonment or being alone.