A rectangular duct is an HVAC air distribution component designed with a rectangular or square cross-section. It is used to efficiently transport air in heating, ventilation, and air conditioning (HVAC) systems. Due to its compact structure, it is highly suitable for installation in false ceilings, wall cavities, and limited space areas.

Rectangular ducts are widely preferred in modern HVAC systems because they provide excellent airflow performance, easy installation, and optimal space utilization in both commercial and residential environments.