EveMax

Hi Master, for 2 bedroom doors directly opposite each other, your remedy is to put a red dot on the door knob/handle, exactly on the same spot. Will it still be as effective if both doors are left open at certain times of the day to let air circulate in the home? Does the red dot need to be relocated/repositioned, wherein it can always see "eye to eye" (e.g. on top of the door jamb area)? Thanks Master.