Check for air leaks: Look for gaps or holes in the ductwork, which can allow air to escape and reduce the overall efficiency of the system. Use duct tape or mastic sealant to seal any leaks you find.

Check duct hygiene: Dirt, dust, and debris can accumulate in the ducts over time, reducing airflow and increasing energy consumption. Cleaning the ducts can help to improve efficiency.

Check for proper insulation: Insulating the ducts can help to keep the air inside the ducts at a consistent temperature, reducing the energy needed to heat or cool the air.

Check the size of the ducts: If the ducts are too small, they may not be able to handle the volume of air being produced by the HVAC system, leading to reduced efficiency.

Check the layout of the ducts: The layout of the ducts can also affect efficiency. Make sure that the ducts are designed to distribute air evenly throughout the home and that they are not taking unnecessary turns or twists.