We recently received some calls from customers about a news item circulating in some media outlets online suggesting that air conditioning can cause COVID-19 to spread between people. As we all know, COVID-19 is spread mostly by human to human contact. Secondly, it can be obtained from surfaces where droplets land which is why we should not touch our faces. I read the research paper about the one case being cited in Wuhan. A team of Chinese engineers identified that both the supply and return vents for the central AC system in a restaurant were right above the table of some infected patrons and may have contributed to people at the next table becoming infected. In this case, the researchers were unable to come to a conclusion about the impact of the central air conditioner. However, they recommended that improved ventilation with fresh air could have made a difference.
People using their home air conditioning are not at risk of infection, especially if they are remaining at home, having no contact with the rest of the population. The key as always is not the temperature of the air but rather the quality of the air. Generally speaking, the poor quality of indoor air can help in the spread of all diseases and other pollutants. One key factor is humidity. COVID-19 lives longer in a dry environment. It is important to ensure that you maintain a humidity level in your home at all times in the range of 40%-60%.
We have been seeing strong interest in other solutions to improve the quality of the air in homes. The first is mechanical ventilation. The installation of an ERV/HRV air exchanger is now in the building code for new homes. We recommend an ERV because it does a better job of managing humidity in our climate. Every home, not just new ones, should enjoy the benefit of continuous fresh air.
The second item is an ultraviolet light. There is no proof yet that a UV light will kill the COVID-19 coronavirus. However, these lights have been proven to kill other viruses. Installation by a knowledgeable professional is important as UV light can damage certain plastics if the light shines directly on them.
Lastly is improved filtration. Filters can’t filter out virus particles on their own but can filter out other particles that the virus might attach itself to. A hospital grade HEPA filter is a good option as is the Lennox Pure Air filter.
There is no silver bullet here. I have always taken the approach in life and in business to minimize risks wherever I find them. For the past 20 years, every home I have lived in has had the 4 solutions above, namely, steam humidifier, ERV, UV light and HEPA filter. These are proven solutions and working together give me the best quality air with the least amount of contamination at all times.
Is it time you to upgrade the quality of air in your home? In the meantime, stay healthy and safe.
Roger Grochmal, P.Eng.
Life Member ASHRAE