The answer to 'how to maintain air filter' is to clean or replace your HVAC air filter regularly. Air filters should be checked monthly and replaced every 1-3 months, depending on the type of filter and your home environment. Clogged or dirty filters can reduce airflow, lower efficiency, and cause your HVAC system to work harder, leading to higher energy bills and potential breakdowns.
To maintain your air filter, first locate the filter, which is typically found in the return air duct or the air handler unit. Carefully remove the filter and hold it up to the light - if you can't see light through the filter, it's time to clean or replace it. You can clean reusable filters by vacuuming or rinsing them with water. Disposable filters should be replaced with the same size and type of filter recommended for your HVAC system.