SuperiorHeatingAndAir.com

why do we have a square shaped duct for central air conditioning system? and not a circular shaped?

why do we have a square shaped duct for central air conditioning system? and not a circular shaped? is there any technical reason behind? thanks in advance

Public Comments

1. Square ducts are cheaper. Flat sheets can be transported to the building site more cheaply, and put together faster and more simply. :-D Just cheaper all around.
2. Convienience mostly. a square/rectangular duct will carry more cfm at the same velocity compared to a round one of the same vertical dimension so it will fit in smaller spaces without reducing flow. They are easier to fabricate on-site too. That said, many ducts ARE round. Mine are for instance, only the plenums are square.
3. Well!!! Air conditioning duct is selected based on its size, shape, and material. Square or rectangular ducts are more preferred because they fit more easily into tight ceiling and wall cavities. But, Round ducts are considered to be the most efficient, allowing a greater volume of air movement per unit of duct.
4. Square shaped ducts are better to use since they fit better within the reinforcements boards inside walls.
5. I think square and rectangular shapes are more convenient to fit in the buildings.