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. The ductwork can either be flexible or rigid, and sometimes fiberglass insulation is added for better thermal control.

The most common use of aluminum duct and fittings 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.

The 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. 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.