Friday, December 18, 2020

As the current pandemic wears on, we continue to learn how this virus spreads from person to person, and how we can prevent this spread. Contrary to its original stance, the CDC now states in a scientific brief that airborne transmission of the virus that causes COVID-19 is not merely likely but commonly occurs in conditions such as enclosed spaces, prolonged exposure, and poor ventilation/air movement.

As our knowledge about the germs that cause illnesses deepens, we revisit the ways that we defend against them. Sometimes we simply need to bolster existing practices, but sometimes we need to shift our way of thinking first to take the necessary precautions.


Five Paradigm Shifts Pertaining to Air Filtration and Illnesses




Air Filters

Commodity product for comfort

Essential product that protects human health

Bypass Air in AHU

Not a significant concern

Compromises air quality, introduces health risks

Appropriate MERV Ratings

MERV 8 filters acceptable in most commercial applications

Filters with a minimum of MERV 13+ rating needed to ensure clean air

Cost-Effective Strategy

Purchase least expensive air filters of desired MERV rating

Upgrade air filters at lowest cost through Total Cost of Ownership (TCO) analysis

Airborne Transmission of COVID-19 Virus

Little to no threat

Primary means of transmission, probability of infection increases in certain conditions


Threat Posed by Airborne Transmission

When a contagious person sneezes, coughs, talks, or even breathes, infectious particles spread throughout the room and contaminate the air in it. However, those same particles can enter the return air ducts of the HVAC system, which then circulates those particles throughout a building.

Bioaerosol distribution

Clean Air Is the Answer

The solution to this problem, as recommended by ASHRAE, involves diluting the concentration of infectious particles with increased amounts of outside air, and cleaning the air with filters with an efficiency rating of at least MERV 13.

Infection Risk vs Filter Efficiency Chart

Upgrading from a MERV 7 air filter to a MERV 13 filter reduces the likelihood of infection by nearly 40%.


AAF Flanders is here to help.

Your local AAF Flanders filtration professional can perform a FREE audit of your HVAC system and recommend solutions that upgrade air filtration, lower costs, and protect building occupants.