Magnetic contacts are mainly used for doors and windows. When the magnet is not in the vicinity of the contact (the window is open) the contact is passed on to the integrated home system. When the window is open the heating can be switched off. Or when the person leaves the home a signal can be given to the occupier that a window or door is still open. There are models that can be recessed into the window or door, and models that can be mounted on their surface.
Figure 38: Example of a magnetic contact for surface mounting. (Illustration source: Peha)