Is using air conditioning safe?

Many businesses are returning to offices up and down the country. It’s likely owners, managers and staff members will have several questions about the health and safety of the building. This includes how to most effectively reduce the risk of spreading the COVID-19 virus.

One query we’re heard mentioned is the safety of using air conditioning in a shared office space.

The chance of coronavirus being spread through air conditioning is minimal. However, it is worth reviewing and potentially changing how you use air conditioning once your staff return to an office environment.

Transmission of coronavirus is thought to occur through respiratory droplets or contact with contaminated surfaces. The respiratory droplets spread through coughs and sneezes, and airborne transmission is not thought to be a significant risk. However, there is a growing body of research suggesting that airborne transmission may enhance risk of infection so it’s worth reviewing your building’s ventilation systems.

The importance of good ventilation

Businesses should try to supply as much outside air as possible, to ensure ventilation is at its highest and any virus spread remains minimal.

Fresh air supply is particularly important in minimising the spread of virus particles. Any ventilation or air conditioning system should be set up to run on full outside air where possible. If you use a centralised ventilation system that uses re-circulation of air, turn this off. You want to be using fresh air, not removing potentially contaminated air and just recirculating it to a different room.

Another top tip is to keep your air flowing. Extend the operation times of your ventilation systems to a few hours before and after you open to ensure the air within your building is fresh. If possible, it is recommended to keep your air conditioning system on constantly at a lowered rate if you aren’t able to set a timer.

Assess the atmosphere

If the air feels stuffy, chances are not enough fresh air is entering the room. Don’t linger unless you’re confident the space is being filled with fresh air regularly. A flow of clean air will help to stop the spread of any infectious diseases.

Opening your windows

If you’re lucky enough to work in an office with plenty of windows, make sure you crack them open for a while when entering a room. This applies even if it’s a bit chilly – it’s more important to let fresh air flow so you can be sure your team are working in a safe environment. Don’t leave windows open overnight, though.

Let your staff members know about the risks of stagnant air, and why keeping the space around them ventilated is so important. Staff members might be able to manually control the opening and closing of windows, or the air conditioning unit in their room. Education is the best way to overcome this and ensure infectious disease is controlled.

Your office is likely to be colder than usual if air is being pulled from outside, and you have windows open where possible. Ensure it’s made clear that bringing a cardigan or wearing thicker clothes is a much better alternative to recirculating air around the office and potentially increasing chance of transmission.

Bathroom facilities

You might think opening windows in your building’s toilets is a good idea. But this could cause contaminated air to enter other rooms… and no one wants that, do they? Stick to using exhaust ventilation systems 24/7 to avoid the spread of virus and bacteria.

Of course, if you don’t have adequate exhaust ventilation in place, then opening a window might be your only option. If this is the case, then we recommend keeping windows open in other spaces to ensure air is consistently flowing throughout your building.


Planned cleaning or maintenance of your ventilation systems should still be undertaken where necessary. However, all site visits, inspections and maintenance work should be undertaken with care. Social distancing must take place, and staff members / contractors must wear the appropriate PPE. Extra care should be taken when replacing or disposing of materials and equipment.

You should also check your filters for viruses frequently, to track for traces of the disease.

Keep employees distanced

You might have a reduced number of employees coming back to work, but you must still maintain social distancing. This is a minimum of 2m physical distance between each person. This is to ensure air does not become contaminating, limiting the spread of coronavirus.

It’s common sense, but employees should be aware of the dangers of coughing and sneezing when around others. Ensure hygiene etiquette expectations are widely promoted around your building.

If you require further guidance, speak to your heating ventilation and air conditioning engineers. You are also welcome to get in touch with our risk management team for advice.

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