Cost

• Flexible ductwork is cheaper to purchase and install than traditional flat metal ductwork.
  
  

Cleaning

• Cleaning traditional ductwork is much easier than cleaning flexible ductwork. According to the Environmental Protection Agency, if flexible ductwork becomes contaminated it needs to be replaced, as opposed to being cleaned. No chemicals or cleaning methods currently exist, as of 2010, that effectively decontaminate flexible or other insulated ductwork.
  
  

Size

• Flexible ductwork comes in a limited number of sizes whereas traditional metal ductwork can easily be custom made to any specified size.
  
  

Strength

• Flexible ductwork has a lower heat and puncture tolerance than traditional metal ductwork. Flexible ducts are obviously not made of metal and have strict guidelines as to allowable contact with sunlight, heat and sharp edges during installation.
  
  

Installation

• Ductwork is typically installed in space restricted areas. Flexible ductwork is easier to install in small areas and around corners than traditional metal ductwork.
  
  

Efficiency

• Studies performed by the Air Distribution Institute and Published in Proc. ACEEE Summer Study 2002, American Council for an Energy Efficient Economy, Washington, D.C., show a significant loss of pressure in flexible duct systems. The loss of pressure resulted in greater energy consumption.