Mechanical Ventilation & Air Conditioning in COVID-19

It is almost after a span of 3 months that all offices, industries, banks have resumed their working in India and moving ahead with Unlock 1.0 with the new normal acceptance to social distancing, wearing masks and more of work in online mode as we all have been prone to the pandemic COVID-19. There is a significant difference of temperature in these 3 months as people need to switch on their air conditioners and dessert coolers to get some respite from the blistering heat. However, there have been several concerns over the use of ACs and coolers in the course of coronavirus COVID-19 pandemic. There are concerns over what can be the most suitable temperature for AC which does not affects our health.  Zee News, News 18, NDTV, The Print, Hindustan Times, Government Swacch India Mission, Times of India, Financial Express all have been discussing this often frequently.


The advisory body of Central Government has 18 page guidelines advising what the optimum temperature of AC and coolers should be amid the coronavirus outbreak. According to the Centre’s advisory, the temperature of the home-run AC should be between 24-30 degrees Celsius and the humidity should be between 40-70 per cent. “Recirculation of cool air by room air conditioners must be accompanied by outdoor air intake through slightly open windows and exhaust by natural exfiltration,” the advisory said.         

        Source: Zee News India

With an increase in humidity, the atmosphere is more prone to dust mites and fungi, two worst culprits for indoor allergy sufferers. The time when ACs are not running is the best duration to keep the rooms ventilated and a circulation of outdoor air to maintain necessary positive pressure in space. It should be followed for commercial, industrial facilities and at one’s home.

The Centre has also issued guidelines on the use of evaporative or desert coolers that are commonly used on North India. In India, the majority of desert coolers do not have air filters but it is possible to fit the filters in coolers during or after installation. The filter prevents dust entry and maintains hygiene. The cleanliness and proper drainage of the water in tanks of desert coolers is a very important consideration to keep water disinfected further maintaining the hygiene of the room. Portable coolers do not draw outdoor air should be avoided of use as these may certainly have ventilation issues.

All these advisory notes are referred from Central Government guidelines in a summarized form.

Explaining why it is a problem to use Air Conditioners at this time, Dr Vivek Nangia, Pulmonologist, Fortis Hospital said, “The problem with central air conditioners is that at the particular moment, this environment is risky and what happens is that in one room people are breathing in the same air, so if one person is infected, chances of others getting the infection are high as everyone is inhaling the same air.”

Talking about ACs in the car, Oncologist Dr Dodul Mondal, from Apollo Hospital said, “Travelling with family members in a closed car space with AC on is safe but if even one person has a cough, viral or cold symptoms, avoid travelling for long hours. As in the closed space, the air will be the same which will be inhaled by every person, so chances of virus spreading are more if the person is infected and doesn’t know.”        

Source : NDTV India

The centralized cooling system definitely is not safe at all, as at any crowded place like a mall, cinemas or any of the offices, a number of unknown people spread the highly contagious infection. The stand-alone ACs that we use in our homes is safe to use but if the infected person is in the same room the virus will definitely spread. It is always preferable to keep the infected person in a well-ventilated room and not use an air conditioner in that case.


Professional bodies like Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE) working in the area of HVAC have also given their guidelines. The Refrigeration and AC Manufacturers Associations (RAMA) said that it is safe to use AC but with few additional precautions. It has joined hands with the Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE) for implementation of air conditioning and ventilation guidelines in the residential and commercial spaces.

It has recommended guidelines, suggesting to keep the temperature of the room AC between 24-30 degree – 24 for humid climate and 30 for dryers, said RAMA in a statement. According to it,”room AC units are designed to maintain the humidity between 40 and 60. In dry climates where humidity is less, it is recommended to increase the humidity by keeping water in a shallow pan,” said RAMA.

It has also suggested “ventilate the room adequately by slightly keeping the window open during running with the exhaust fan running in the adjacent bathroom if possible and by keeping doors and windows open when AC is not operated.”                               

Source : News 18

RAMA has also insisted to increase the frequency of filter cleaning. The adequate cleaning of filter ensures pure air in the room and maintains hygiene.

While for the central air conditioning system, CPWD has also adopted the protocols given in the ISHRAE guidelines after a prolonged shutdown. It has suggested keeping the temperature setting between 24 and 30 degrees and during non-working hours and weekends, to keep the air circulation system running at all times without cooling.

RAMA and ISHRAE slowly and steadily are running a nationwide awareness campaign for the air conditioning and ventilation guidelines to optimise residential, commercial and hospital buildings for COVID-19 prevention as issued by ISHRAE.

Prof. Umesh Gurnani,
Head, Department of Mechanical Engineering,
University of Engineering & Management (UEM), Jaipur


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