Most filters on an air conditioner should be cleaned or changed once every three to nine months. The frequency may depend on the recommendations in the owner's manual for the specific unit and on the amount of allergens or dust in the geographic area.
Most air conditioning filters easily slide out to clean or to replenish with a fresh, new filter. When cleaning filters, homeowners can vacuum lint, dust and residue from the filter with a vacuum hose. With some models, the filters can be rinsed in water to remove dust particles. Regular replacement or cleaning of filters can provide better filtration and allow the air conditioner to run more efficiently.