HVAC maintenance

Can an HVAC Duct Spread COVID-19 in Offices, Stores and Schools?

There’s something you use every day that could be spreading COVID-19 without a second thought to anyone. Your heating, ventilation, and air-conditioning systems could be the culprit. In large spaces like corporate buildings, schools, and grocery stores, the air could be spreading the virus through its vents.

Moving Indoors

Excessive heat forces people indoors. This means air conditioning systems are working overtime. The cooling systems don’t allow much outdoor air to circulate through the interior. Outdoor areas and well-ventilated areas allow better airflow. There’s a debate that COVID-19 spreads through the air. It is documented that the virus is spread mainly through inhaling infected air droplets or touching contaminated surfaces.

Air Conditioning Systems

When an HVAC system is ducted, the air currents carry larger viral particles a further distance. Some systems like this simply need an upgrade. They need to be reconfigured to bring in more fresh air from outside. Fresh air means the same “old” air filled with germs isn’t recirculating through the building. This can be an issue with older air conditioning systems. It’s important to change the airflow patterns indoors to reduce transmission. This includes reducing turbulent airflow with a vertical laminar and working to ensure the air is at a steady speed.


Some people think air filters are a good solution to fresh airflow. There are only two thpes of air filters that can efficiently remove particles of a coravirus. A Minimum Efficiency Reporting Value filter and a High-Efficiency Particulate Air filter can remove almost 99.9% of the tiny particles. The problem is that there is still room for the tiniest particle to get through the filter. Ratings are assigned to MERV filters according to how accurately they are able to filter out larger particles. Most homes and commercial buildings have a rating of MERV 12 or lower. A rate of 17 is needed to potentially remove coronavirus particles.

UVC Light

Far-UVC light technology might be able to help clear virus particles out of the air in big buildings with air conditioning systems. A germicidal lamp using UVC light can kill a microorganism like the coronavirus. This technology has been around for centuries killing bacteria, yeast, viruses and mold. Researchers at Columbia University Irving Medical Center tested this technology on two types of coronaviruses. They used a misting device to disperse the virus into the air while the germicical lamps were used on them. Their research showed that continuous exposure to the light for 25 minutes each day killed 99.9 percent of each virus. Some people worry this type of light can harm the human body; however, far-UVC light cannot get through the tear layer of the eye or the exterior layer of the skin.

The Last Word

Using an HVAC system will not excel this virus if proper precautions are taken. Time will tell if the UVC lights will grow in popularity and help wipe out the virus inside building. It’s important to stay outside as much as possible and always practice social distancing.