Use in Concrete Slabs
Not all houses have basements or crawl spaces underneath them. PVC ductwork allows heating and cooling pipes to be run underneath the floors of houses built on concrete slabs. Standard metal ductwork is not made for such an application. PVC ductwork gives the builder or owner more flexibility when designing a house if he chooses to install his grates in the floor, rather than on the ceiling or in the wall.
In addition to structural considerations, PVC prevents corrosion from moisture and radon infiltration.
Resistant to Corrosive Fumes and Chemical Vapors
Although it is more of an issue in commercial and industrial applications, than in homes, PVC allows for the flow and venting of harmful gases and vapors that can pollute and have an adverse affect on health in confined spaces. Since heating and cooling is essential in these environments as well, it is a crucial consideration in order to comply with health and safety regulations set in place by federal and state agencies.
Better Insulating Capacity
PVC is made of polyvinyl chloride, which has better insulating abilities than standard metal ducts. PVC and plastics are generally considered to be insulators, whereas all types of metals (whether in pure form or as alloys) are considered conductors. They have a tendency to conduct and disperse hot and cold temperatures, as well as electrical currents. As it pertains to heating and cooling, PVC tends to show its advantages more in larger homes and buildings, where the longer length of metal ductwork allows for increased dispersion of heating or cooling energy along its path, rather than at its ultimate destination.
Higher Material Cost
Although PVC-coated ductwork is excellent for its application, PVC and its fittings cost more at the outset because PVC costs more to manufacture than its metal counterpart, even if it costs less to actually install. However, PVC has cost-saving advantages in the long run because it requires less maintenance and is more energy efficient than metal ductwork.