I don t know why but i have taken metal pipe apart to find a lot of crud which i don t think would live in flex duct.
Flex duct vs sheet metal duct.
Also i think spider webs are more likely to form in metal versus flex.
Their shape and size also allows them to be installed in locations that would not accept full sized sheet metal ductwork.
Cost of installation supplies.
Flexible ducts are made out of corrugated plastic often wrapped in insulation.
Sheet metal ducts are less likely to incur dangerous mold and growths because their surfaces are non porous and smooth.
Some sheet metal air ducts are lined with an external or internal fiberglass duct liner.
Flexible ducts are fairly easy to install and will often cost less than the rigid ductwork.
I ve only been building since 1995 so i can t say for certain why we left the sheet metal guys behind but i suspect it was manly for cost reasons.
This is because they re more versatile and flexible.
Flex ducts are better for existing trunk and branch heating and cooling systems.
In this video i ll make a case for going back to rigid metal ducts for your trunk lines and keeping your flexable ducts to the last 10 or less of a.
Here are the itemized costs for the most common types of ductwork and supplies needed to complete installation.
Fiberglass lining is used to insulate air ducts from heat loss or to avoid condensation in cases where the supply air is very cold or there is a high ambient humidity in the plenum.
I am not hating on metal pipe but flex duct is more practical in many applications.
While sheet metal ductwork tends to be a better long.
In comparison to metal duct flex duct is easier and faster to install.
While they tend not to last as long as sheet metal they are very cost effective.