Dryer Vent Safety
What is the safest dryer vent hose?
Dryer vent ducts come in a variety of materials. Most dryer ducts are round and 4 inches in diameter. Some are flexible, and others are rigid. Dryers may come with the manufacturer’s specifications for ducting to use with a particular model.
1. Aluminum Foil Duct
Made of flexible aluminum foil, this is the most common type of dryer transition ducts. Transition ducts connect from the dryer to the main duct that runs to the outside vent. Foil duct can accordion from about 1 to 8 feet, which is usually enough for most installations. Transition ducts must not be concealed inside walls or other building cavities and usually have a maximum allowed length of eight feet. Foil duct is held in place with dryer clamps or large hose clamps. Metal tape can be used, too, but clamps make it easier to remove the tubing for cleaning. Make sure that this type is approved for your dryer and allowed by local code.
2. Semi-Rigid Metal Duct
Semi-rigid metal duct is flexible and similar to foil ducting but quite a bit more rigid. Semi-rigid is a transition duct and should not be concealed in walls or floors. Although semi-rigid metal duct is often stronger, has a smoother interior and can catch less lint than foil duct, it is more common to find foil duct than semi-rigid. Semi-rigid metal duct is typically installed with clamps.
3. Rigid Metal Duct
The rigid metal duct is the only suitable duct material for concealed duct installations. Concealed duct installation is the portion of the duct run inside walls, floors, or other areas where the duct is not fully visible. Rigid metal duct is available in aluminum and galvanized steel. Being very smooth on its interior, air flows through with little friction, and it catches the least amount of lint of any duct material. Because rigid duct cannot be bent, it is assembled with elbow fittings that allow the duct to turn 45 or 90 degrees.
4. Plastic or Vinyl Duct
The flexible plastic (usually vinyl) duct is similar to aluminum foil duct but has a thin plastic wall rather than metal foil. Despite its popular use for many years, the plastic duct is not allowed by most building codes. The ribbed interior of the flexible duct easily catches lint and is highly flammable.
WARNING If the duct becomes blocked with lint, the duct can become very hot and potentially catch fire. This hazard has resulted in numerous house fires. Plastic duct is the least-safe option. The bottom line is, don't use it.