text: You need to keep your filter changed frequently, vacuum out your vents and do an air exchange at least monthly.  \n\nThe air exchange is something that our allergist introduced us to.  You simply open all of your windows for about 30 minutes, turn on the ceiling fans (if you have them) and turn the fan on the air conditioner on.  This is supposed to let out the old air and bring in fresh air.  \n\nWe have to use the a/c at home because we all have asthma and allergies.  We have a hard time breathing if we just use the windows.