Created with the allergy sufferer in mind, the Air Quality System uses disposable filters. There is no cleaning required and no direct contact with used filters. Simply replace the filters 1-2 times per year, depending on use. Changing the filters is easy, no tools required. The change filter indicator light on the control panel will notify you when the filters should be checked and changed. Note: Filters with significant visible buildup should be changed whether the light has activated or not. The superior performance promised of the Vornado Air Quality System 500 is realized only when genuine Vornado Allergen Reducing Filters are used. Others may claim their filters can be used in the AQS 500, but those filters are not designed for our units, and in most cases are not as effective and may not last as long, costing you money. Maintain the health and comfort of you and your family. Contains 4 filters. Vornado’s Automatic Filter Refill Program for Vornado Air Purifiers offer a convenient way to receive regular shipments of Vornado filters for your Vornado Air Purifier! Eliminate the hassle of remembering to reorder. Maintain the high efficiency of your Vornado Air Purifier by never running out of new filters. Receive FREE SHIPPING on all air cleaner filter refill orders when you set up a product subscription. Click the “Subscription Wizard” button above to set a customized schedule to receive your filters – conveniently billed automatically. The Air Quality System replacement filter, part number MD1-0014/0015 works with model AQS 500.