To replace an air purifier filter, unlatch the front of the unit according to the manufacturer's directions and remove any pre-filters. The filters themselves should be removed with care, as they may have accumulated dust and debris. Insert new filters, paying attention to the airflow indicator to achieve proper alignment.
Most air filters use some sort of pre-filtering system. Washable pre-filters should be removed and cleaned according to the manufacturer's directions, and then allowed to dry thoroughly before replacing. Carbon pre-filters must be replaced with new ones, and they should be renewed every three to six months. These layers keep large debris and dust from clogging the more delicate filters inside the purifier.
In most cases, the main filters responsible for removing allergens fit tightly into the air purifier's airway, ensuring that all room air passes through the filtration media and not around its edges. If a filter appears loose, check to make sure that it is the correct filter for the air purifier. Using an incorrect filter can result in substandard performance.
Filter changes are also a good time to give the entire air purifier a cleaning. Since dust-laden room air is drawn through the unit, dust and grime can build up on the surface of a purifier. Wipe these surfaces with a damp cloth to remove accumulated dust and prevent it from migrating into the blower assembly of the air filter, where it could interfere with normal operation.