Not Just Any Filters Will Do! Why Air Filter Strength Matters

Low indoor air quality is an endemic problem around the country. As more homeowners become aware of the problem, they want to find solutions. Unfortunately, these “solutions” often involve purchasing expensive filters and air purifiers that don’t actually do the job they need from them. If you are looking to improve your home’s indoor air quality in Austin, TX, or the greater Austin area, we recommend you call our NATE-certified, dependable HVAC technicians to help with finding the filtration system that works for your home.


The simple description of an air filter is that it’s a mesh of fibers or another medium that traps airborne pollutants as air passes through it. Basically, an air strainer. When most people think of air filters in their homes, they think about the filter that’s on the HVAC cabinet or the plastic permanent filters in window AC units. These filters only do a rudimentary job of filtration, catching large pollutants like dust and lint. Some HVAC professionals refer to them as “rock-catchers,” which gives a pretty good idea of how effective they are when it comes to filtering smaller pollutants.

There are many types of filters, from the simple panel filters made from fiberglass to pleated filters made of polyester with extremely thick weaves. One powerful filter you may have heard about is the HEPA filter, which is often used in hospitals and industrial facilities.


Minimum efficiency reporting value, or MERV, is the rating system that expresses how well a filter traps pollutants. A filter can have MERV between 1 and 20, and the higher the number, the smaller the particles it can trap. The plastic cleanable filter found in window AC units has MERV 1–2. A MERV 20 filter is the type used for clean rooms in high-tech facilities. Residential filters for central AC and heating systems usually fall between 8 and 14.


The mistake people make when they attempt to find filters on their own rather than work with IAQ and HVAC professionals is to pick out as powerful a filter as they can afford. The problem with this is that a filter can be too strong for the HVAC system in a house. A thicker weave filter puts more resistance against airflow and may end up blocking airflow entirely.

Even worse than the negative effect, this has on comfort (you can’t enjoy cooled/heated air that never reaches the rooms!) is the effect it has on the HVAC system. When pressure increases in the ventilation system, it puts extra strain on the blower fan and can damage the system.

You want to apply the “Goldilocks Rule” to air filters: not too weak, not too strong, but just right. Our IAQ professionals will locate the “just right” filtration system for your house, and we can pair the filter with a purifier if you need additional air cleaning power. We keep Austin residents comfortable year-round!

Intelligent Air Services serves the greater Austin area. The Intelligent choice today makes cents tomorrow!