Ventilation and air conditioning: what's the difference and how does it relate to health?

Heating, ventilation and air conditioning (HVAC) – are techniques that  provide ambient comfort in homes, offices and other indoor spaces. Although ventilation and air conditioning both provide cooling, they also differ to a certain extent.

Ventilation ensures there is a permanent exchange of air in indoor spaces. This is important because it creates a pleasant indoor temperature, but most of all: it keeps the air healthy. A ventilation system continuously replaces 'old' air with fresh air from outside, so that germs and other pollutants such as CO2 or other bio-effluents are removed from the ambient air.

Some focus points to bear in mind regarding work environment ventilation:

• Did many people gather in one small space, such as a meeting room? Then ventilate the room afterwards: open as many windows and doors as possible for about 10 or 15 minutes. This should also be done regularly in other rooms and spaces.
• Chinks and air vents are a good start, but a mechanical ventilation system is the best way to ensure permanent air renewal.
• Ventilation is just as important in winter as it is in summer. After all, viruses reign supreme during winter months.

Air conditioning controls the ambient climate in the workspace. An air conditioning system is the best way to achieve this: in addition to maintaining a pleasant temperature, it also controls humidity. Most systems incorporate a filter that cleans the air in the room and redistributes it at the adjusted temperature. This method does not involve fresh air from outside. For this reason, extra ventilation is essential.

(Oscillating) fans are a cheaper alternative to air conditioning systems, but these are a lot less safe. After all, they distribute the ‘used’ air with filtering it first and help germs to spread. For this reason, fans are not recommended in spaces used or frequented by many different people. The same is true for mobile air conditioning units. If you do decide to use these units, please make sure the airflow is not aimed directly at people.

This Q&A looks more closely at the risk of spreading COVID-19 through ventilation systems and air conditioning.To counter the rise of the coronavirus, the European Association for Heating, Ventilation and Air Conditioning (REHVA) has published a number of guidelines for the correct maintenance and use of HVAC installations. Here is a summary of the most important tips:

• The basic rule: a maximum supply of fresh air is essential.
• Systems that completely dispose of used air are the best ones. In these systems, old air does not come into contact with fresh air.
• If filtration is unavoidable, make sure the filters in your system are installed correctly. Follow the maintenance schedule to keep them clean. Please click here for all guidelines related to the maintenance of your air conditioning system.
• If you do not have a ventilation system, ventilate the rooms by regularly opening windows and doors. Make sure that no air is circulating from zones with a potentially high concentration of virus particles, such as sanitary facilities, to ‘cleaner’ zones, such as offices.
• A room’s humidity level does not affect the spread of coronavirus. There is no need to adjust the settings on your humidification system.
• Limit the number of people in your office buildings. Congregations of many people in the same small room – such as meeting rooms or canteens – should be avoided. Organise your employees to work from home as much as possible.

Additional reading: Q&A | Can the coronavirus spread through ventilation or air conditioning systems ?