The best way to improve the efficiency of your HVAC system is to perform regular maintenance. This includes changing the air filter every 1-3 months, cleaning the condenser coils, and checking for any leaks or blockages in the ductwork. Additionally, you should have your system inspected and serviced by a professional HVAC technician at least once a year. This will help to ensure that your system is running at peak efficiency and can help to identify any potential issues before they become major problems.