Five practical signs

Look for dark dust halos around supply registers, debris inside return grilles, a musty or stale odor when the system starts, rooms with noticeably weak airflow, and dust that returns quickly after renovation work.

What a sign does not prove

Any one sign can have more than one explanation. A blocked filter, a closed damper, or debris in an accessible return can affect airflow. The inspection should identify what is actually visible before work is recommended.

Information to prepare

Note which rooms are affected, when the issue started, the last filter change, and any recent construction or water leak. Photos of registers and the mechanical area are useful.

HDC Improvement Inc. serves homes and businesses across Long Island, including Hampton Bays, Southampton, and East Hampton.