The answer to 'air filter not cooling' is that a dirty or clogged air filter is a common cause of an HVAC system not cooling properly. A dirty air filter restricts airflow, which reduces the system's efficiency and ability to cool the home effectively.
Some common symptoms of an air filter issue include warm air coming from the vents, the system running constantly but not reaching the set temperature, and higher than normal energy bills. The solution is to replace the air filter, which is a simple DIY task that most homeowners can do. However, if the problem persists after changing the filter, it's best to call a professional HVAC technician to diagnose and address any underlying issues.