Air conditioning systems, fans?
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Air conditioning systems, fans? No! Air cleaners!

Which devices really provide protection from virulent accumulations of aerosol in the room air?

How are room air and the Corona virus linked with each other?

Do fans or air conditioners enhance the distribution of droplets and aerosols in the room?

Not only in times of Corona, dangerous superficial knowledge, untruths and recommendations about air conditioners and air cleaners spread like a wildfire in social media. Air conditioners are blamed to be virus spreaders. And simple fans are hyped to provide protection from infectious aerosols in the air. No matter whether the window is open or closed. What is right? What do you need to know about air conditioners and fans with regard to Corona virus?

How are room air and the Corona virus linked with each other?

Virologists agree with each other: The Corona virus mainly spreads by breathing, only a small amount is distributed by smear and droplet infections. When breathing through the mouth and when talking, thousands of aerosols – tiniest particles of saliva – are emitted into the room.

These particles are invisible to the naked eye. They spread further than the recommended minimum distance of 1.5 - 2.0 m, remaining in the room air for several hours. If a person is infected, these floating particles are contaminated with viruses or bacteria. If infectious aerosols are inhaled, viruses deeply penetrate the pulmonary alveoli via the respiratory tract.

Respiratory masks with particle filter offer protection from aerosols in closed rooms, as well as high-frequency air cleaners as the TAC V+ from Trotec. However, protective masks do not protect from inhaling infectious aerosols. They only keep away large droplets.

Are inside and outside air equally dangerous?

Outdoors, aerosols emitted when talking are distributed and diluted by natural air movements. For this reason, the risk of inhaling other people’s aerosols when they talk is relatively small. However, in closed rooms with no air exchange, the concentration of aerosols increases with every additional person. Undiluted accumulations of aerosols float throughout the room, and the danger of inhaling infectious viruses from the air is comparatively high.

How does an air conditioning system affect the danger of infection?

Air recirculation devices only cool down the room air, but there is no fresh air supply from outside. Besides, commercially available air conditioning systems are not equipped with a special HEPA filter – which is part of the air cleaner TAC V+ or TES 200 with H14 HEPA filter that allows to filter airborne viruses or bacteria. Present viruses in the room air are extensively distributed in the room air with the air flow. This is why “virus spreader” is a word.

  • Air conditioning systems with air recirculation do not offer protection against viruses such as the Corona or influenza virus. Accumulations of aerosol are not diluted or filtered out.
  • Aerosols carrying viruses are distributed through the blown-out air of the air conditioning system into the farthest corner of the house. Even if you stick to the distancing regulations, you'll inhale the aerosols.
How does an air conditioning system affect the danger of infection?
Does a fan protect from an infection if the window is open?

Does a fan protect from an infection if the window is open?

Some virologists recommend placing a fan in front of the open window to transport the germ-laden room air to the outside.

In theory, this is right. The air current produced by the fan sucks in room air and blows viruses out of the window. In practice, however, this is quite unrealistic! In summer, an open window with the fan switched on may be quite pleasant.

But what do you do in winter, when it's freezing outside with temperatures below zero? And how are you able to concentrate on your work in the office, if traffic noise booms through the open window? In retirement homes and treatment centres, it cannot be recommended either. Elderly people in retirement homes have an increased need for warmth. An open window may have severe consequences.

  • Indeed, a fan in front of an open window does reduce the risk of infection. The reason for this is the dilution effect which results from the fresh wind of outside air.
  • However, this kind of protection from infection is not quite practical and cannot be realised in the cold season and for older people.
  • If the outside temperature is equal to the inside temperature, the outside air cannot flow into the room.

Does a fan protect from an infection if the window is closed?

In closed rooms, a fan provides the same infection protection as an air conditioning system with air recirculation. No protection at all! Without a supply of fresh air from outside, the room air will be merely moved, but not diluted. Moreover, fans don't provide any kind of filtering effect.

  • Therefore, a fan in a closed room does not provide protection from Corona virus. Accumulations of aerosol are not diluted or filtered out.
  • The opposite is true! Aerosols carrying viruses are distributed through the blown-out air of the fan into the farthest corner of the house. Even if you stick to the distancing regulations, you'll inhale the aerosols.

How reasonable is cross-ventilation in terms of protection against infections?

Cross-ventilation will always allow air changes in the room. The air contaminated with germs is drawn to the outside and fresh air flows into the room. However, airing rooms like this always carries risks. Infectious aerosols always spread through the entire room before they escape to the outside, especially in offices or restaurants where many people stay. All persons remaining in the air current will inevitably inhale these aerosols.

Does a fan protect from an infection if the window is closed?
An efficient protection against viruses in the room air can only be provided by a high-frequency air cleaner, such as the TAC V+ that offers HEPA filtration and high air flow rates

An efficient protection against viruses in the room air can only be provided by a high-frequency air cleaner, such as the TAC V+ that offers HEPA filtration and high air flow rates

The mobile air cleaner TAC V+ purifies room air as effectively as air purification is carried out in hygiene-sensitive hospital operation theatres.

Made possible by the extremely high air flow rate and the innovative H14 HEPA virus filter. The room air is sucked in near the ground, cleaned from bacteria and viruses by means of the HEPA filter and finally released into the room as germ-free air.

Depending on the room size, the room air is circulated and cleaned up to 20 times per hour. The result is that suddenly occurring accumulations of aerosol are diluted with clean air in the area of your head to such an extent that the virus load and risk of infection will be remarkably reduced!

No installation, no complicated connection. Simply plug in and provide for the maximum infection protection possible!

High-frequency air purification protects both personnel and patients

If the room air is kept free from germs and viruses, the airborne risk of infection will be minimised likewise. Trotec high-frequency air cleaners such as the TAC V+ are exactly designed to perform this task for they efficiently and quickly reduce the intensity and time aerosol accumulations and suspended matter stay in closed rooms, creating zones with an extraordinarily reduced risk of infection for both patients and personnel.

Directly at the installation site, the mobile air cleaner TAC V+ creates a “clean zone area”, flooded with purified air and filtered from viruses. Within this zone, the surrounding air nearly completely stays free of airborne germs and viruses because the TAC V+ is able to take in large volumes of contaminated room air and to carry out effective H14 HEPA filtration. Moreover, the device is able to purify room air zones in a flexibly adjustable manner with clean air that has been filtered from viruses and aerosol particles.

Effective against bacteria and virus accumulations

Trotec high-frequency air cleaners are equipped with HEPA filters of class H14 which filter out more than 99.995 % of all fine suspended particles larger than 0.1 µm with a transmittance of only 0.005 %. Or in other words: No more than five of 100,000 particles pass the H14 filter. Thanks to this unique feature, these kinds of high-performance filters are also used in operation theatres or comparable hygienically sensitive areas in order to produce clean air. This way, you create optimum conditions to keep room air and breathing air in waiting and treatment rooms free from germs and viruses in times of spreading epidemics.

Well-known viral strains such as SARS-CoV, MERS-CoV or Covid-19 have a particle size of 0.005 to 0.1 µm. Most of the time, they form accumulations with other particles (such as saliva or suspended matter) which increases their size up to 0.4 µm or 0.5 µm. These accumulations are referred to as germs and will be filtered out reliably by the Trotec H14 air cleaning filters.

All H14 HEPA filters by Trotec fulfil the highest quality standards that are obligatory for bacteria and virus filtration.

  • Each H14 high-performance filter is tested individually and is assigned its respective serial number
  • The test report is enclosed as certificate in duplicate with each H14 filter
  • The original test certificate can be filed with the documents for the device. If required, the copy can be attached to the air cleaning device.
  • HEPA high-performance H14 filters are tested in compliance with EN 1822 and EN 60335-2-69.

Also suitable for any TAC air cleaner with H13 filter

You can also insert a H14 HEPA filter by Trotec into your TAC air cleaner if you already possess a TAC device. The H14 filters are available as an accessory, e.g. for the professional air cleaners TAC 3000, TAC 5000 or TAC 6500. Simply replace the H13 filter in the filter compartment with a H14 HEPA filter.

Professional air cleaner with H14 HEPA filter by Trotec

High performance air cleaner TAC V+. Effective protection against aerosols and viruses in the air.

This product video will tell you all about the virus protection effect, the function and the advantages of the TAC V+ high-performance air purifier from Trotec. According to the current state of science, the coronavirus is transmitted in over 80% of cases by aerosols in the room air. The aerosols contaminated with viruses are produced when speaking, coughing or sneezing and often remain in the room air for a very long time. Inhaling the infectious aerosols can infect people in the room with pathogens. Trotec offers the solution for this: The TAC V+ high-performance air purifier filters the air with an efficiency of 99.995%, which corresponds to the air quality of operating rooms. The room air contaminated with aerosols is diluted, pressed to the floor, sucked in and filtered. In the vicinity of the air purifier, aerosol and virus-free clean air zones are created. The viruses bound in the filter are automatically killed by heat, so that the filter remains hygienically clean for a long time. By using the TAC V+ air purifier from Trotec, you will protect your employees, customers and guests. Ideal for, for example, restaurants, fitness studios, hotels, open-plan offices, medical practices, shops, and supermarkets, etc. So that finally more people, customers and visitors can stay indoors again without the risk of infection.

Effective air purification technology for clean breathing air

The aerosol accumulations are invisible to the naked eye and spread several metres into the room, flowing through interior spaces as swathes of fog do – see the following real-time video: The TAC V+ sucks in large volumes of potentially contaminated air near the ground, filters out nearly all viruses and suspended matter within minutes and generates clean air filtered from viruses which is guided back into the room. The result is that suddenly occurring accumulations of aerosol are diluted with clean air in your breathing area to such an extent that virus load and risk of infection will be significantly reduced! Just as the room is entirely foggy at the start of the video to be completely fog-free after the treatment in the end, the TAC V+ can also free your room air from particulate matter, fine particulates or aerosol accumulations carrying viruses.

Optionally also available in further colours

In addition to the standard yellow paint, the TAC V+ is optionally painted in basalt gray, white or bronze and can also be ordered as a stainless steel version.

Optionally also available in further colours

Whether for sale or for rent: Trotec offers the right air cleaners

Whether you like to rent a high-frequency air cleaner on a short-term basis or whether you prefer buying it to benefit from a long-term use – at Trotec, devices and respective filters are always available from stock. Our expert consultants are also happy to advise you with regard to integrate your device into your AC system.

Purchasing a device: If you have any questions, please contact us via email: or give us a call at +49 2452 962-400. Renting a device: Please contact our TKL hiring centre directly – by email: or under +49 2452 962-160.


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