electrostatic filters are designed to last a lifetime if they are maintained properly we recommend cleaning your filter at least every month electrostatic filters are very easy to clean they can be vacuumed off or washed with water we recommend taking your filter outside and washing it with water at least every 60 days as this effectively releases the dust that gets trapped in the electrostatic media layers if you are unsure whether your filter needs to be cleaned or not you can hold it up to a source of light and make sure that it is still transparent a dirty filter will block most of the light coming through the filter a flashlight also works good to check the transparency of the filter make sure the filter is hosed off in the proper direction locate the airflow arrow on the edge of the filter and make sure the filter is washed in the opposite direction of this arrow the idea is to drive the dirt out of the filter not to push it deeper into the filter if the filter is exposed to pet hair cigarette smoke or cooking fumes it is a good idea to spray a mild detergent on the filter prior to washing with water commercial electrostatic filter cleaners are available at most stores or you can use a drop of dishwashing detergent in a spray bottle filled with water spray the filter thoroughly with the cleaning solution but don't let the solution dry on the filter do not spray the cleaning solution on the filter in direct sunlight allow the cleaning solution to penetrate the filter for a minute or two and then hose off with water allow the filter to drip dry outside for 5 to 10 minutes before reinstalling the filter does not have to be completely dry but it should not be dripping wet when reinstalling you you