An aluminum duct is a passageway made of aluminum that mainly is used to move air, such as with air conditioning or heating systems, throughout a structure or building. Heating, ventilating, and air conditioning (HVAC) ducts are typically made of aluminum. Aluminum ducts also are used with home dryer systems; as aluminum doesn't rust, this type of duct is perfect for removing the warm, moist air expelled from the clothes dryer. The ductwork can either be flexible or rigid, and sometimes fiberglass insulation is added for better thermal control.
The history of aluminum dates back to 1854, when the American chemist Charles M. Hall developed a method of extracting large amounts of aluminum from a mined substance known as bauxite. His method is used today to produce almost all of the world’s aluminum. Aluminum ductwork benefits from aluminum’s natural qualities, namely its light weight and its natural resistance to corrosion. Being non-ferrous, aluminum does not rust.
The most common use of aluminum duct is that in the heating and air conditioning industry. Flexible and rigid duct is often used to route conditioned air with a home or building. Aluminum duct is used because of its high strength to weight ratio—a very lightweight section of rigid duct can be spanned large distances without needing to be supported. Its flexible form is used because of aluminum’s ability to stretch; a flexible aluminum duct can be bent hundreds of times and still maintain an air tight cavity. Insulated forms of both of these can be used to minimize transfer of heat between the contents and the environment, making HVAC systems more efficient.
Another very common use of aluminum duct is as a dryer duct. Clothes dryers use high heat to dry clothes, converting the water in the clothes to water vapor that is then vented out of the home. Aluminum duct is commonly used in this application because of its resistance to corrosion. A duct can transport moist air for many years without the threat of rust. The cost of these aluminum ducts is generally low due to the small diameter of duct needed.
Since aluminum duct can either be rigid or flexible, installation is typically quite simple. Rigid units can be supported by metal or plastic strapping attached to the structure itself, or they can be directly mounted to a surface using large brackets. Flexible sections of duct can be allowed to rest on an uneven surface, or hung using metal or plastic strapping. Since aluminum ductwork maintains an airtight cavity, it doesn't need to be supported in a way that maintains a straight line of delivery.
