Walk behind most dryers and you will find one of two kinds of duct joining the machine to the wall: a smooth rigid metal tube, or a ridged, accordion style flexible hose. The two look close enough at a glance, but they behave differently the moment lint starts moving through them, and that difference shows up in both performance and safety.
How each material handles lint
Rigid metal duct has a smooth interior wall, so lint slides along it with little resistance. Flexible duct has a grooved interior, and lint catches in those grooves on every pass. Over time, a flexible run collects far more than a rigid run carrying the same laundry, which means shorter intervals between cleanings to keep pace with the same household.
Where flexible duct still makes sense
Flexible duct is not wrong everywhere. The short, visible section right behind the dryer often calls for some give, to join the exhaust port to the wall opening and to let the machine be pulled out and pushed back for service. Used that way, as a short exposed transition hose rather than the main run, flexible duct is a sound and common choice.
Where rigid duct is the better choice
Any section that travels through walls, floors, ceilings, or an attic, out of sight and hard to inspect, belongs in smooth rigid metal. It holds its shape instead of sagging or kinking, resists crushing when something leans against it in a crawlspace, and its steady diameter makes it far easier to clean from end to end.
Vinyl flexible duct specifically
Older homes sometimes still have vinyl, non-metal flexible duct running the full length of the dryer vent. That material is outdated for dryer venting, since it sits close to a heat source, sags and kinks more than foil style hose, and does not hold up over years of use. Homes in towns like Somerville, Bridgewater, and Dover, where older housing stock is common, still turn up with it behind the machine.
Retrofitting an older vent run
Plenty of older New Jersey homes have a full flexible run from before smooth metal became the norm. When the time comes to replace it, switching the concealed portion to rigid metal improves airflow and lint clearance and takes hot exhaust away from material that was never meant to carry it. That work often happens on the same visit as a dryer vent cleaning.
Aluminum and galvanized steel rigid duct
Rigid metal comes in two common forms, aluminum and galvanized steel, and both give the same smooth interior that sheds lint better than flexible material. The choice between them comes down to the particulars of an installation, weight and how the sections get joined and sealed, rather than one being broadly better for dryer venting.
Semi-rigid duct as a middle option
Some installations use semi-rigid metal duct, which flexes enough to work around a tight corner while keeping a smoother interior than foil hose. It is not a stand-in for rigid duct on a long concealed run, but it earns its place in a cramped mechanical closet or an oddly framed wall cavity where a straight rigid piece cannot be worked into position.
How material choice affects cleaning
The material behind your dryer also sets how thoroughly the run can be cleared. A rigid duct's steady diameter lets cleaning equipment travel the full length predictably. A flexible duct's ridges, and any sags that have formed along the way, hold debris in places that are harder to reach, which is one more reason an older flexible run may want attention sooner even after a thorough cleaning.
If you can reach behind your dryer, look at what is clamped to the exhaust port and how far it travels before it disappears into the wall. A short foil transition feeding rigid metal is the setup you want. A foil hose that vanishes into the wall and never reappears is the one worth raising at your next visit, since replacing the concealed portion is ordinary dryer vent installation work rather than a renovation.