If they are not cleaned periodically dirty ducts can potentially recirculate germs and infections. Whichever way you look at it, that’s bad for indoor air quality. With regards to Covid-19, the public perception has been that the virus is transmitted only through direct contact, such as through droplets and from surface contact. However, recent evidence has shown dirty ventilation systems may be behind transmission too.
Reports of Covid-19 spreading through air ducts The National Post reports of a recent Covid-19 outbreak at a restaurant in the Chinese city of Guangzhou as a result of airborne particles being carried by the HVAC system. The index patient (someone known to be Covid-19 positive) was not seated near other diners, and the distance between them was assessed too great for the virus to have been transmitted through droplets. Authorities concluded the only possible explanation was droplets being circulated through the air conditioning. Another revelation comes from the cruise ship, Diamond Princess, which was widely in the news during the early stages of the outbreak. It is now strongly suspected that contaminated air circulating through the air conditioning system, vent cleaning was not possible when the ship was quarantined, led to a large number of passengers becoming infected.
Recent advice on HVAC cleaning in light of Covid-19 In light of these developments, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has released a statement urging cleaning and changes to ventilation and filtration systems to reduce the risk of infection spread. Researchers at the University of Alberta have also been granted funds from the government to find ways to curb spread through the HVAC. Regardless, regular air duct cleaning, replacement of filters and sanitizing common touch points look set to be effective ways of combating Covid-19 spread.
Signs of dirty/clogged filters and ducts There are a few obvious signs that the air duct, filters and motors of a ventilation system are dirty. If your HVAC is experiencing any of these symptoms it could point to dust and debris clogging the system. Excessive noise during operation Particles or dust being blown out of ducts Reduced efficiency (greater than normal heat, energy consumption) Mould accumulation around the premises People coughing or complaining of nasal congestion
How regular air duct cleaning can improve indoor air quality Indoor air quality can affect the health and wellness of the occupants of the building. It is possible for germs to be blown around the premises, and excessive dust not being caught by the filters can lead to allergies. Regularly cleaned ducts make buildings safer and more comfortable for occupants. Ease respiratory ailments due to trapped dust and debris Clean dust and mould spore build-up deep in the HVAC system Potentially reduce the risk of bacterial and viral transmission
Note: Clean air ducts cannot stop the spread of Covid-19, they can help reduce the risk of airborne transmission if such exists. Please continue to wash your hands, sanitize your surroundings regularly and practice physical distancing. What causes dirty air vents? Dust, lint, hair, pet dander and flakes of skin get caught on fine dust filters and accumulate along the length of the air ducts. Over time, they can form layers of matted surface that becomes a breeding ground for dust mites, allergens and infections.
How often should you clean your HVAC ducts? The National Air Duct Cleaning Association (NADCA) recommends cleaning air ducts once every 3 to 5 years. However, in light of the Covid-19 pandemic, a more frequent cleaning is advisable. There is no exact formula for how frequently ducts must be cleaned, so you must consider your environment and need to maintain the health of occupants. Speak to an GTA Duct Cleaning representative to schedule cleaning at your home, office or industrial facility. (416)333-5833