Ductwork installation is the process of putting the network of tunnels that run from an air conditioner and furnace to the vents in each room. It begins with the "rough-in" phase of cutting holes in walls and ends with the installation of return air ducts.
After cutting holes in the walls for ducts and return air, the next step is to place the evaporator coil and furnace-air handler in the desired spot. Then, it is time to start installing the primary trunk lines. Many of these main lines have branches to send the air to the many vents that are present in buildings. Installing ductwork of one size onto a piece of another size requires a piece known as a transition. About every 8 feet, a metal hanger supports the duct, and curved pieces of metal called S cleats combine ducts, as to "drives," or metal pieces folded onto themselves to allow them to slide onto the different sides of the duct.
The next step involves installing branch ducts onto the transition takeoffs from the larger duct. Branch ducts run all the way to the register in the wall. A branch duct is generally round, but it takes an elbow boot at the end to give it a square facing and make it compatible with the register. Installing the return air ducts after the installation and painting of drywall completes the installation process.