The Honeywell F500A1000 HEPA Air Cleaner is a whole house HEPA style air cleaner. It is typically attached to your existing return air duct system but CAN be installed as an independent system. Filters for the Honeywell F500A1000 must be replaced as follows. HEPA filter every 36 months, prefilter every 12 month and charcoal filter every 3 months.