The answer to 'how to maintain air filter' is to regularly check and replace your HVAC air filter. This is an important maintenance task that helps keep your system running efficiently and improves indoor air quality. You should check your air filter every 1-3 months and replace it when it appears dirty or clogged.
To maintain your air filter, first locate the filter, which is usually in the return air duct or the air handler unit. Carefully remove the old filter and inspect it - if it's coated with dust, pet hair, or other debris, it's time to replace it. When installing the new filter, make sure the airflow direction arrows point in the correct direction. Also, be sure to use the right size filter for your system.