The answer to 'preventive maintenance blowing cold air' is that the issue is likely caused by a problem with the HVAC system, such as a blocked air filter, refrigerant leak, or issue with the compressor. The most common symptoms are the HVAC system blowing cold air even when it's not running, poor airflow, and high energy bills. Solutions can include replacing the air filter, repairing any leaks, or servicing the compressor, but some issues may require a professional HVAC technician to diagnose and fix.
It's important to address the issue promptly, as a problem with the HVAC system can lead to further damage and higher repair costs if left untreated. While some basic maintenance tasks like changing the air filter can be done DIY, it's generally recommended to have a professional HVAC technician perform the annual preventive maintenance to ensure the system is operating safely and efficiently.