The answer to 'air filter not working' is that a clogged or dirty air filter is a common cause of HVAC system problems. A dirty filter can restrict airflow, causing the system to work harder and less efficiently. This can lead to higher energy bills, uneven heating/cooling, and even potential damage to the HVAC components.
Some common symptoms of a bad air filter include reduced airflow from vents, the system running more frequently, and even the air handler or furnace making unusual noises. The solution is typically to replace the air filter, which is a simple DIY task most homeowners can do. However, if the problem persists or you're unsure of the cause, it's best to call a professional HVAC technician to diagnose and resolve the issue.