AC Vent Filters Are a Bad Idea

Your AC has two types of vents. Supply vents where the air blows out and return vents where air is sucked back in. During our many years in the indoor environmental business, we received many questions about using filters in the supply vents. People would tell us they had things blowing out their vents and wanted to stop it. They would use all sorts of materials as a supply vent filter. Supply vent filters are a bad idea.

First, they hide a problem without solving the problem. If you have “things” blowing out of your AC vents, then you have a problem. There could be many sources for this “stuff”. Possible sources are as follows:

  • duct system is dirty and needs cleaning;
  • your air handling unit is dirty and needs cleaning;
  • your ducts are not properly sealed and are sucking in dust from the attic; or
  • your ducts have some sort of internal lining that has started to deteriorate.

These are all problems that need to be addressed.

Aside from hiding your problem, vent filters can actually make a dirty system dirtier. Especially if you have any mold in the system. This is because the filtering media will catch the spores. When the system cycles off, the spores will have warmth, darkness, and moisture. These are the ingredients for mold growth. Do you want to farm mold in your vents?

In addition, your AC system was designed for certain airflow. If you restrict the airflow, then you create backpressure on your system. This causes the components to work harder. So, now you are reducing the life of your equipment and increasing the amount of energy your equipment uses. Do you want to squander money on electricity?

Some of the allergy supply companies carry material to cut and put in your vents. These people may know lots about allergies, but they do not know about AC systems or indoor environmental hygiene. Do not put filters in your supply vents.

Your AC system should have a proper fitting filter on the return side. By placing a good fitting, high quality filter on the return vent, you will remove particles from the air before they can enter the AC system. A good filter will keep your air handling unit, coils, and ducts clean. If your filter doesn’t fit properly, it can be as bad as having no filter.

Broward AC Filters makes filters that fit. We don’t make filters for supply vents. Filters for supply vents are a bad idea. We make filters that will fit your return vent and that is a good idea.