A unit’s air filters are responsible for collecting and trapping dust, dirt, and other allergens, to ensure the air in the room remains clean and safe to breathe. Run the filters under water and let dry completely, Use a vacuum to clean lint/dirt/dust too. Air filters on average can be cleaned for up to 100 timesbefore its recommended to purchase new filters. Convenient placement: Easy to remove & insert filters. Each PTAC requires 2 filters. (keep in mind when buyingenough filters) . Recommended to clean filters monthly. Replaces 4130915