How Does an Air Filter Work?

One very important component of the air conditioning system is the air filter. Its primary function is to remove particulates from the airflow to keep the workings of the air conditioner clean and efficient. It also helps keep the ducts clean, which helps keep indoor air clean and fresh. It’s very important to replace air filters when they get too dirty, as the accumulation of dust makes them less and less efficient, eventually allowing dust and debris to contaminate the condenser coils. But how does the air filter actually work?

The air filter is placed at the air intake, where the fan pulls air into the air conditioning system. The filter is made up of thousands of tiny fibers, coiled around one another to make a very fine mesh. Air flows through this mesh, carrying millions of tiny particles that need to be filtered out. The way in which the particles interact with the fibers determines how they are filtered. Generally, there are three main ways that the particles get filtered.

The first method of filtering is called impaction filtering. This is where some of the particles carried by the airflow impact directly onto the fibers. Large particles that can’t pass between the dense weave of fibers will be the easiest to filter out, but even some of those particles that are much smaller will impact with the fibers and thus end their journey trapped there.

Another way the filter catches particles is by what is called interception filtering. If a particle gets close enough to the filter fibers, the particles are attracted to the fibers and wind up sticking to it. This method is usually effective for particles that are smaller than those that normally get caught by impaction methods.

The very smallest particles, those that can potentially slip by the fibers without being intercepted, are filtered by another method called diffusion filtering. Because these particles are so very small, they ricochet off the large air molecules and swirl around in the turbulence created as the air molecules bounce around trying to get through the maze of fibers. Because of this turbulence and the collision, the particle will be bounced into nearby fibers and caught.

This is how an air filter, even if the fibers are not close enough together to catch everything by impaction, can still filter out a huge amount of airborne particulate matter from the airstream going through your air conditioner. Not only is this important for the efficient working of the system, but also for your health and wellness. If you have any questions about filtration systems or air conditioner maintenance or other concerns about your air conditioning system, be sure to contact All Day Air Cooling and Heating today at (239) 357-0727.