People around the globe are in the midst of dealing with and trying to prevent the spread of the current coronavirus strain, COVID-19. As people spend more time indoors and avoid public areas and large crowds, you may be wondering if your HVAC system can spread the virus.
How do Coronaviruses spread?
Coronaviruses, including COVID-19, spread like most colds and flus – via touching something that someone with a virus may have contacted, or by being near a person with the infection that coughs or sneezes. Given how small the organisms are, they could remain in the air for up to 6 minutes after coughing or sneezing, thus making your HVAC system a potential mechanism for spreading the germs. However, there are a few things you can do to prevent the spread of poor quality air or microorganisms throughout your home.
How to prevent your HVAC system from spreading ‘dirty’ air
The most common forms of air cleaning in modern HVAC systems is the use of filters. Nearly all heating and cooling units sold in the United States in the last 20 years contain advanced filters that can be purchased and replaced every 90-180 days. Depending on the type of filter you purchase, they do a moderate to very good job of purifying the conditioned air being distributed in your home. (Generally, the more expensive the filter, the less stuff can get through it.) These include HEPA filters and similar, but note that they will have a stated ability to prevent the spread of pathogens as small as 0.20 microns. In comparison, most coronaviruses range from 0.06 to 0.14 microns in size – so they may well slip through if they have been aerosolized.
The next options to help with air purification in your HVAC setup is the use of UV lights (specifically, UV-C). This is often present in many kitchens and other commercial facilities, but there are several options available as well that can be added to an HVAC system. The concept behind using UV lights is that they kill many types of pathogens and microbes that something like a traditional filter may leave behind. It is important to note that there is no confirmed research to-date that confirms UV-C can destroy COVID-19. Similar research has been conducted for other types of coronaviruses, including SARS and MERS.
There are generally two types of UV-C solutions to add to your HVAC systems: (1) Residential air purifiers made by Honeywell and Fresh-Aire UV that get added to the supply duct work and contain a UV lightbulb that can be replaced annually. The bulb effectively ‘inactivates’ pathogens in the air that pass by it. Note that this will differ depending on the system and the bulb strength, so please check the specifications before you order. (2) For non-traditional HVAC units, like mini-split systems, UV strip lights are available that can be added to the unit and which the air will pass just as in a traditional system.
Summary
No matter what options you choose, be sure to take the recommended precautions during cold and flu season as recommended by healthcare professionals. But also be sure to change your HVAC filters regularly and, for those that want to take prevention to the next level, consider adding a UV light to your HVAC system.