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Coronavirus And Air Conditioning

In January, nine people in a restaurant got COVID-19 despite being at three adjacent tables more than 1 meter (3.2 feet) apart. On the Diamond Princess cruise ship, passengers were quarantined. Due to poor hygienic practices, air re-circulating through vents and close-quarter confinement, the initial diagnosis of 10 cases exploded to 705 within fourteen days. These cases validated that coronavirus could be propelled by strong airflow from an air conditioner.


So, what are some safeguards that could be taken to mitigate transmission risk? Since shelter-in-space was announced, the following public health practices have been recommended:


  • Social distancing measures

  • Avoid touching surfaces

  • Do not touch your face

  • Wash your hands

  • Wear a face mask


A distinction between residential spaces, smaller public places and larger public sites is useful.

If you don’t have sick people in your house, vents will not introduce COVID-19. As new items are brought into your home, sanitize them and clean your hands to prevent the spread of the virus. A sick person at home should be isolated from other family members. The most prudent thing to do is to open a window for air circulation. Stale inside air, contaminated with viral droplets, mix and get diluted by introducing more outside air. However, a room may not have a large enough window or other conditions, such as asthma or extreme weather might require using an HVAC. One option would be to cover or seal the return vents with a plastic cover or tape. Alternatively, filtered HVAC systems or air purifiers are good “engineering controls” to separate hazards from the environment.

A John Hopkins study found that hospitals with a high ventilation rate remove air from a room where a virus could be found. Additionally, hospitals are using “negative-pressure rooms” for COVID-19 patients. Finally, hospitals sanitize surfaces and suppress unnecessary traffic. For smaller public spaces, say air-conditioned restaurants, experts are suggesting these additional safety measures:


  • Increase space in-between neighboring tables

  • Reduce Capacity

  • Have Employees Wear Masks

  • Limit how long diners can stay

  • Frequently wipe down and disinfect surfaces

  • Use disposable menus

  • Pay through touchless methods


When available, it is advised to use the natural ventilation of open windows. If it is necessary to use HVAC, temperatures should be set higher than usual. Warmer weather appears to reduce the virus life on surfaces. Larger particles from sneezes, say from 10 micrometers to 100 micrometers, travel less than six feet and settle to the ground in 10 minutes or less due to gravity. Particles about 0.3 micrometer could remain in the air longer and could be propagated further via air flow. If possible, setting HVAC blowers lower is recommended.

Besides virus, the ductwork of HVAC systems could have mold, rodent droppings or other allergens. Dehumidifiers built into the system would help to mitigate some of these hazards. In its absence, duct cleaning is a solution. The cleaning could be executed without a chemical sanitizer. However, if needed, a solvent such as Oxine is approved against COVID-19. Routine duct cleaning has the added benefit of making HVAC systems operate more efficiently. If it has been more than two years since your last cleaning, call Acosta Home & Air Pro at (914) 875-3266 for a speedy job. Our services begin at $300 for smaller systems but will increase for bigger systems with problems that have accumulated over several years.

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