Plastic vent covers are generally cheaper compared to other types of vent covers and they can certainly do the job well albeit some problems. Below are two of the most common problems that you will likely encounter if you use plastic vent covers at home.
1. Melting and Deformation
One of the most common problems that you will encounter if you use cheap plastic vent covers is melting. Note that cheap plastic may not be able to withstand prolonged exposure to heat so as hot air passes through the vents for several minutes or hours for than matter, the plastic vents will melt. The melting process is not instantaneous and the severity of the damage depends largely on the amount of heat that passes through the vent. After being exposed to heat for sometime, the plastic vent can become deformed and you will need to replace it sooner than you want to.
Unlike steel vent covers that can withstand tremendous amount of pressure, cheap plastic vent covers are not so strong and are prone to breakage especially when exposed to extreme conditions. Louver type plastic vent that deflects the air to different directions breaks easily compared to the grate or grill type vents so there is a big possibility that you will need to change your vent especially if you live in an area with extreme temperatures.