Flex Duct Vs Sheet Metal Duct

Metal ductwork needs design measurement and installation by or with the help of an hvac professional.

Flex duct vs sheet metal duct. Air flow in a steel duct tends to travel smoothly in a coil like motion. Sheet metal ducts are less likely to incur dangerous mold and growths because their surfaces are non porous and smooth. If any duct product should be banned it s duct board. 25 feet should it be ductboard or metal and is hard pipe runs preferable over flex.

While they tend not to last as long as sheet metal they are very cost effective. Rigid metal is installed then mastic is applied to air seal then insulation is applied on the outside so there is less chance of fibers getting into your air stream. Well if we re not going to use flex what s left. There s duct board rigid fiberglass with a foil facing but in my opinion that s worse than flex.

While flex ducts work best for short runs in a trunk and branch system metal duct works best for entire air distribution systems. You mentioned that you were considering re insulating your current metal duct work. While sheet metal ductwork tends to be a better long term choice flexible ductwork has the advantage of relatively low upfront cost and versatility. If i am going to have a supply plenum run for approx.

Rigid metal is more likely to be installed without constrictions whereas flex duct can easily be pinched down. Air flow in a flex duct tends to tumble probably because of the rib like intrusion every inch or so. Flex must be oversized at least one duct size. Most often flex duct is used to reduce cost or in places where metal duct work will not fit.

Even when doing this the flex duct creates much more resistance. Their shape and size also allows them to be installed in locations that would not accept full sized sheet metal ductwork. Flexible ducts are made out of corrugated plastic often wrapped in insulation. Duct board vs metal plenums supply is on perferable over the other.

More than likely. If your budget allows you may want to consider resealing your duct work with a mastic product. Flexible ducts are fairly easy to install and will often cost less than the rigid ductwork.