An experts in Sarasota HVAC services, Baker & Sons is passionate about building and maintaining HVAC systems that help you breathe easier—whether it’s with smarter HVAC systems, cleaner air ducts, or most importantly, better air filters.

In this blog, we’re going to touch on the three basic types of air filtration that can trap unhealthy airborne particles in your home. This information can help you figure out which particles your HVAC system is capable of catching, and which might be flying straight through your filters without a problem.

Impaction FIltering

Impaction filtering is when particles are pulled out of an airstream by being forced to make a sharp bend in their trajectory. When large particles are pulled toward an impaction AC unit, they gain too much momentum (because of their relative heaviness) to leave the unit’s airstream. These particles are sucked into the unit and make impact with the “collection surface”—also known as your air filter. At this point, the smaller remaining particles can stick to the fibers of the filter or pass through the filter altogether, while the largest particles are trapped in the filter because they’re too large to pass through the holes of the filter. Impaction only traps particles 0.4u or larger in a HEPA system.

Interception Filtering

The holes in air filters will always be larger than 0.3u to 0.1u particles—but HVAC air filters manage to trap these particles anyway. How is this possible? It’s all due to interception filtering. Even if particles are small enough to pass through the holes of an air filter, they will most likely stick to filter fibers—but only if the distance between the particle and the filter fiber is smaller than the diameter of the particle itself.

Let’s break this down further: if a particle is 2u in size, and it comes within 1u of a filter fiber, it’s probably going to stick to the filter. But if a 1u particle is 2u away from the filter fibers, it’s probably passing right on through and back into your air supply.

This type of filtering handles some incredibly small particles… but not the smallest ones.     

Diffusion Filtering

For those teeny-tiny particles under 0.1u, there’s only diffusion filtering. As air moves quickly past your air filter, these nearly weightless particles when to swirl around in the turbulence of the air, eventually colliding and “mingling” with larger gas molecules in the area. These particle/molecule combos will spin out of control as they approach the filter, landing themselves right inside filter fibers

This is next-level air filtering right here—most particles that you’d want to trap for easier breathing are usually larger than 0.3u, with dust particles usually coming in at 0.5u-50u. However, if you severe or live in a dustier, dirtier, or more polluted area, diffusion filtering could do wonders for your indoor air quality by filtering out smog, carbon, and airborne viruses.

Talk to Your Sarasota HVAC Team

If you have any questions about the capabilities of your air filters or your HVAC system, call the team at Baker & Sons. We’re happy to help you find the right HVAC system for your air quality needs. Get started today.