The answer to 'why is my air filter' is that a dirty or clogged air filter is a common issue that can cause problems with your HVAC system. A dirty air filter can restrict airflow, leading to reduced efficiency, higher energy bills, and potential damage to your HVAC equipment. Symptoms of a dirty air filter include reduced airflow, higher utility bills, and poor indoor air quality.
The solution is to regularly replace or clean your air filter as recommended by the manufacturer, typically every 1-3 months. This is a relatively simple DIY task, but it's important to use the correct filter size and type for your system. If you're unsure or the problem persists, it's best to call a professional HVAC technician to diagnose and address the issue.