Ducting plays an important role in your home’s HVAC system. If your ducting is installed incorrectly or isn't the right kind for your system, it will put added stress on your heating and cooling appliances, which ultimately leads to additional expenses down the road. From rigid to flexible ductwork and everything in-between, here is a short guide to selecting the right kind of ducting for your home.
Rigid ductwork is easily the most common form of ducting found inside homes. This type of ducting comes in different materials and shapes, from sheet metal to fiberboard and rectangular or cylindrical. Some varieties even come fully insulated. Although rigid ductwork is more expensive than other varieties, it's easily the most durable.
The downsides to using rigid ductwork are that it's difficult to install and cannot be used in tight places. When installing rigid ductwork, use steel support brackets to ensure the pipes do not rattle and make sure each joint is properly sealed with tape or an air seal of your choice.
Sheet Metal Ductwork
Sheet metal ducts are the most popular form of rigid ductwork. These ducts are usually made from either galvanized aluminum or steel. The aluminum variety is great because it's lightweight and relatively easy to install.
Aluminum also does not tend to grow mold or bacteria due to its non-porous surface. The steel versions, however, can accumulate mold and other growths during their lifetime. When selecting the right kind of sheet metal ductwork, look for the kind that comes equipped with insulation wrap, which helps prevent air leakage over time.
Fiberglass ducting is simply sheet metal ducts that are lined with fiberglass. The fiberglass can be installed either internally or externally and is great for dampening the sound of the HVAC system. There are, however, a few major drawbacks using fiberglass ductwork. Given time, the fiberglass lining can break down and begin to leak particles into the air.
These particles can become a big health concern for anyone in the home. This type of ducting is also difficult to clean because you have to be careful not to ruin the fiberglass. Without a proper cleaning, mold and bacteria can grow within the walls of the ducting, which also leads to quality of air issues.
Fiberboard ductwork is a great alternative between traditional sheet metal and fiberglass ducting. Fiberboard ducts are constructed from strands of fiberglass that are compressed and coated with resin.
The material is then laminated with foil to seal out moisture. Fiberboard is a well-insulated product that's great for your home’s cooling and heating needs. The downside to using fiberboard, however, is it's susceptible to mold growth because of its porous surface. Because of this, fiberboard should not be used in ventilation applications.
Flexible ducting is typically used in tight areas that cannot accommodate rigid pieces, such as tight bends or near air supply outlets. These tube-shaped ducts are constructed from wire coil and flexible plastic and come fully insulated.
The advantages of using flexible ductwork are that they are less expensive than their rigid counterparts, are fairly easy to install, and fit in hard-to-reach places. The downside to using these ducts is that they are easy to install incorrectly and need to be properly sealed and supported to prevent air leaks.
Installing Flexible Ductwork
The biggest mistakes people make when installing flexible ductwork are sealing issues and not giving the pieces enough support. You should avoid sagging ducts at all cost, spacing supports every four feet of ducting.
When attaching two pieces together, make sure the connection is secure and seal it with tape or mastic. You can also use metal clamps for a tighter fit, though these are not necessary in most instances. Finally, avoid bending the pieces in sharp angles as this will cut down on air flow.