Traditionally, Ventilation and Air Conditioning ducts have been
manufactured with Rectangular cross sections. The Rectangular Duct can
be easily adapted, e.g. to restricted ceiling voids and plant rooms;
however, often at the cost of efficient airflow design and possible cost
A Circular Duct System normally performs better and offers a
more economical solution, which is the reason why it always pays to study
and compare the ductwork design before selecting which type is to be
used for a specific application.