A:Answer Hey there, thanks for reaching out. This light means you need to clean the filter. The air filter behind the front grille should be checked and cleaned at least every 30 days or more often if necessary. To remove it, you'll need to slide the filter from the left side of the unit and remove the filter. You can then clean it with warm, soapy water. Finally, rinse and let the filter dry before replacing it. Do not clean the filter in a dishwasher. If you need anything else, just let us know. We're always happy to help. - Guy@GEA