There are several different reasons why you might be looking into installing heating ducts into your home. You might be replacing old ducts or installing new ones into a new home or addition. This job is a complicated one, requiring a lot of hard work. It's also a job you want done right, so, if you aren't sure what you're doing, it's a good idea to let the professionals handle this one. Here's what the process should look like:
Planning
The first thing that will need to be done is to figure out the size of the ducts you'll need and how many feet. Home heating ducts come in sizes between 4 and 14 inches of diameter and in lengths of 25 feet. The diameters correspond to the amount of air a particular duct can carry. Each room in your home will need a different amount of air to keep it heated. This amount is measured in cubic feet per minute (CFM). The necessary CFM will need to be determined for each room, and then you'll know which ducts to use.
Finally, the routes the ducts will take will need to be mapped out.This will let you know how many sections of ducts you'll have to purchase for each room (these sections will need to be trimmed to fit the routes they're going to follow).
Installing the Ducts
To prepare your home for the ducts, paths will need to be cleared along the duct routes.This could mean cutting through joists or relocating wiring. All throughout this process, your contractor will need to pay close attention to all pertinent building codes regarding ductwork.
Next, the ductwork can be assembled, using scissors or tin snips to cut the ducts to the necessary sizes. To connect two duct sections together, fold back the insulation and covers (called "jackets") of the two pieces and place a metal duct sleeve (about 4 inches in length) between them. Wrap each duct section with duct tape around the spots where they meet the metal sleeve. Apply metal clamps to each side for added support and then roll the insulation and jacket back into place. Wrap some more duct tape around the seams to help secure the duct sections and their jackets into place.
The ducts will need to be installed inside the walls of your home, using both horizontal and vertical sections. The vertical sections go between floors and are called "stacks." Sections that are more than 5 feet long will need to be supported using metal clamps, hangers, saddles, or wire. This will prevent the ducts from sagging, which constricts airflow. Holes for vents will need to be cut in the ceiling, floor, and/or walls, depending on where you want the air to come out. Floor vents or vents close to the floor are ideal, because warm air rises. Once the ducts are run to the vent location, simply install your choice of vent cover over it.
Once your ducts and vents are installed, make sure you clean them and change the air filters periodically. That way, the warm air filling your home will be clean as well!