Heating and cooling systems (HVAC) incorporate an air filter to clean the incoming air before it is conditioned and distributed back to the living space.

In many HVAC systems, the air filter has two distinct jobs:

The first is to protect the HVAC system, dust and other particles can easily cause component wear and can adhere to parts like the blower fan or coils, reducing system efficiency.
The second job is to remove dust, pollen, pet dander and other contaminants from the air to improve indoor air quality and reduce the symptoms of conditions like asthma and allergies.

There are several types of air filters available, classified by type and MERV rating. The most common types of air filters include:

Pleated Filters

Pleated filters use large pieces of fiberglass, polyester, or other synthetic materials folded into pleats to increase surface area and remove more contaminants. However, without filtration enhancement, even filters with a MERV rating of 8 or above cannot clean the air of particles less than 3 microns, as the particles cannot reach the filter via air flow with significant efficiency.

Fiberglass Filters

Fiberglass filters are inexpensive and reusable or disposable and will catch 80% of particles 50 microns and larger. They filter out large particles to protect the HVAC equipment and provide maximum airflow, but do not filter any of the small harmful contaminants that affect your health.

While pleated filters and fiberglass filters make up the majority of filters used in residential applications, HVAC systems can also be designed to use one of the following air filters.

HEPA Filters

High Efficiency Particulate Arrestance (HEPA) filters do a great job of catching particles 0.3 microns and larger in size. However, HVAC systems are designed to only move particles greater than 3 microns. As a result, the smaller harmful contaminants affecting your health never make it to the filter. HEPA filters also require significant pressure to force air through, making them restrictive for use in most HVAC systems not designed for HEPA filters.

Carbon Filters

Carbon air filters use activated carbon to remove contaminants in the air utilizing a chemical adsorption process and are rated for areas less than 105 degrees Fahrenheit. However, many HVAC systems are not in air-conditioned spaces and the operating temperature can often exceed 105 degrees Fahrenheit, impacting the effectiveness of the filter.

Electrostatic Filters

Electrostatic filters use an electric charge to attract particles as they pass through the filtering medium. They perform better than disposable filters or basic pleated filters and can have MERV ratings up to 15.

Question: If most air filters do a good job for what they were intended to do, then why do we have contaminants, fine dust and odors remaining in our space?

Answer: The majority of the particles < 3 microns never reach the filters!

Approximately 98% of all particles in the air are less than 3 microns. These particles include allergens, odors, gases, mold and mildew spores, airborne pathogens, and volatile organic compounds (VOCs).

The CosaClean system is a compact, modular version of the CosaTron Contamination Control System-successfully used in commercial applications for over 60 years. CosaClean electronically increases the particle size allowing your air filter to perform as it was intended.

Picking the correct air filter and changing the filter on the manufacturers recommended schedule seems like such a mundane chore, but in reality, it’s one of the most important tasks you can do for your HVAC system and your health.