Different Types of Duct Systems

Hard Pipe:

Hard pipe provides approximately 50% more airflow than flex. It is a quieter duct system, easier to balance airflow and due to the hard surface of the metal helps prevent mold growth. A hard pipe system requires each piece to be cut, screwed together, supported, taped, and wrapped externally with insulation. With a hard pipe system, air moves freely down the tubes and allows more flexibility in air balance.

Flex Duct:

Flex ductwork can be a death sentence to almost any air conditioning system, if not designed and installed correctly. The basic product design problem is the inherent airflow design deficiency that is built in, namely the wire wall ribbing. The air flow encounters restriction when it travels against the wall ribbing, and when the ductwork installation is poor with problems such as kinks, insufficient diameters, no sub-plenums, and excessive lengths, the overall performance suffers because the system works much harder and results in lack of comfort and higher utilities. Flex duct is insulated from R-6 to R-10 and is sized to flow at no more than 600 feet per minute. Central City Air always strives to install ductwork that is properly sized and supported in the attic to provide a duct system that operates up to its design capabilities.


Ductwork carries air from the air plenum to the supply outlets. Silver flex ductwork installed correctly is a good duct system. Hard Pipe, sheet metal ductwork, properly designed and installed delivers air with the least amount of resistance. At Central City Air, we take a combination of these types of ductwork and custom engineer them for superior airflow and comfort. Flex duct is insulated from R-6 to R-10 and is sized to flow at no more than 600 feet per minute. Our sheet metal ductwork is round, externally wrapped and sized to flow up to 900 feet per minute. A Hybrid system will provide up to 50% greater airflow than flex duct alone.