HVAC and Airborne Viruses: Separating Fact from Fiction

The U.S. Centers for Disease Control and Prevention as well as the Environmental Protection Agency have brought attention to the fact that indoor HVAC systems can affect airborne viruses. This concern has come even further to the forefront as the country and the entire world navigate the COVID-19 pandemic. With that in mind, let’s look at some common misconceptions in addition to some truths that deserve more exposure. We want to help you separate the facts from the fiction.

Fact: Ventilation Can Distribute Airborne Viruses

A ventilation system can certainly distribute some airborne viruses throughout a home. However, this does not apply to all airborne viruses. Distribution occurs more with germs that can be transmitted through aerosols. In such cases, inadequate ventilation can exacerbate the situation because, just as with pollution particles, those aerosols will accumulate over time. On the other hand, strong ventilation or even natural ventilation, such as opening a window, can mitigate this buildup by introducing fresh air.

Fiction: Strong Ventilation Alone Is Enough to Combat Airborne Viruses

Strong ventilation helps to ensure that virus-laden aerosols do not accumulate and increase your risk of infection. Your greatest risk of exposure, however, is immediate contact. You should socially distance within a home from people who are sick. You should regularly wash your hands thoroughly with warm water and soap for at least 20 seconds. It is also important to control dust within the home because it can serve as a means of transmission for many different pollutants and contaminants.

Fiction: High and Low Temperatures Thwart Viruses

While the temperature does affect virus propagation and transmission in some scenarios, there is little evidence that making your home particularly warm or cool will affect your immediate exposure. The truth when it comes to humidity is a bit muddier. Heating your home in winter lowers the relative humidity. Lower indoor RH coupled with higher outdoor RH has been shown to increase flu transmission, and it is theorized—but not proven—that using a humidifier in winter could make people less prone to ailments common during this season.

Fiction: All Air Purifiers Kill Viruses

Air purifiers, air cleaners and air filters—these terms are often used interchangeably—come in many different styles and are intended for a range of purposes. A common type of air cleaner that simply employs an activated charcoal stage will eliminate odors, gases, vapors and a wide array of other contaminants, but it will not kill or trap viruses. Be mindful that air purifiers can have various stages. When considering an air purifier, you should know what you want to achieve along with what the various stages in a particular product achieve.

Fact: HEPA Is Effective Against Viruses

HEPA stands for high-efficiency particulate air. In the U.S., a standard HEPA filter can remove 99.97% of particles 0.3 microns in size or larger, and a medical-grade HEPA filter can remove up to 99.99%. These particles include viruses. Be mindful that HEPA filtration works through a process known as diffusion. Even if a virus particle measures 0.125 microns, it can be trapped due to this process. To use a HEPA filter, you require an air purifier that supports it. It is not recommended that you swap out your HVAC filters for HEPA filters due to restricted airflow.

Fact: Ultraviolet Light Is Effective Against Viruses

UV air purifiers use short-wave ultraviolet light, which is also called UV-C light, to kill microorganisms and pathogens. You may also come across the term UV germicidal irradiation or UVGI. Such purification is often paired with HEPA filtration and available in both portable and whole-home configurations. Note that not all UV air purifiers are created equal and some will actually diminish air quality through the creation of ozone.

Helping Puyallup Maintain Clean Air

Healthy air is important for you and your entire household. At Puyallup Heating & Air Conditioning in Puyallup, we appreciate that and have been helping homeowners throughout the South Puget Sound region for more than 70 years. In fact, we seal air ducts with the Aeroseal formula, which not only limits leakage but also stops pollutants and contaminants in your ducts. Our other services directly related to airborne viruses include heating and cooling maintenance with a focus on indoor air quality and the installation, maintenance and repair of in-duct whole-home air purifiers. Our company also installs and repairs all manner of heating and air conditioning equipment and tankless water heaters.

Call Puyallup Heating & Air Conditioning today to learn more about these services or schedule an appointment.