Kim's Parent's House is the residence of Kim's parents. This is seen in Book 6, when Scott travels to visit Kim to help clear his mind. It is presumed Scott stays there for the time being.
Later, Kim leaves the house with Scott to go to a nearby wilderness sabbatical, where Scott tries to rekindle his relationship with Kim. However, Kim grossly rejects, leading to Scott having The Glow and fighting his evil double-self, NegaScott. After purging his mind, Scott returns to Toronto to face Gideon.