Hi, only the pre-filter is washable, and you can wipe the dust off the filters with a dry cloth.
To enjoy a better performance, we suggest you to replace the filters in 6-8 months. And the time will vary according to the service length of the purifier and your surrounding environment. If the purifier serves for 24/7 or your surrounding air quality is in a high pollution, then the filters need to be replaced in a shorter time.
