The Science Behind Healthy Humidity - 40-60% RH

Predominant humidification studies

Yale University 2020 -  Seasonality of Respiratory Infections

A meta-study from the Yale University School of Medicine shows how sunlight, temperature and humidity affect the transmission of viral respiratory infections. The triggers of these infections include flu viruses, cold viruses and coronaviruses, including SARS-CoV-1 and 2.

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Study by Dr. D. Noti (2013) -  Airborne Influenza Virus Transmission

Breathing manikins with nebulizers were used to mechanically "cough" nebulized influenza viruses (real flu) into the air and to examine the infectivity at different humidity levels. If a relative humidity of 40% is maintained indoors, the risk of infection by the virus is reduced in aerosols considerably.

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Yale University (2019) -  Low humidity impairs barrier function and resistance against influenza infection

This study set out to understand the impact of low humidity on the immune system's defences against the Influenza virus. Genetically modified mice, which resist flu infection in a similar way to humans, were used to test the effects of humidity, at either 10 or 20%RH compared to 50%RH, on flu infection.

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"If I get sick, take me to the museum."

Dr. Stephanie Taylor, one of Condair's medical consultants: "If I get sick, take me to the museum, because the international indoor climate values ​​for museums specify keeping the indoor air between 50 and 55 ± 5% relative humidity and 20°C, which are the ideal conditions for a perfectly functioning human immune system!

However, these values ​​are not specified in standards for hospitals - the art objects are often better protected than living people. And Condair wants to change that by:

  • Drawing attention to the importance of air quality for health - especially, but not only, in times of Corona.
  • Providing homeowners with hygiene whole-home air humidification solutions as well as our expertise and knowledge to make interiors and homes healthier.

  • Ensuring indoor spaces have a relative humidity of 40-60% RH to esnure health and performance at home and at work.

Dry air not only makes you sick - it is also very uncomfortable

We spend 90 percent of our time in closed rooms. The lack of humidity in the interior has a significant impact on well-being and leads to:

  • Generally weakened immune system

  • Respiratory infections

  • Dry, irritated skin

  • Headache and reduced work and concentration performance

  • Eye discomfort

  • Sleep disorders

  • Voice disorders

  • Allergies and asthma

  • Painful electrostatic discharges

Our immune defense works best at 40-60% RH

Air that is too dry also damages the ingenious protective mechanism of the respiratory tract: the mucous layer dries up, becomes tough and prevents the cilia from moving so that viruses and germs can no longer be transported away. This creates a significantly increased risk of colds. Older people, children and people with sensitive mucous membranes such as allergy sufferers and contact lens wearers particularly suffer from this.


Moist airway mucous membranes

The cilia of the airways move like grass in the wind. On top of them lies a layer of viscous mucus on which germs and viruses “stick” and are prevented from penetrating the body.

Moist airway mucous membranes

Dry airway mucous membranes

When the air is dry, the mucous layer also dries out. It becomes hard and firm, so that on the one hand it can no longer be moved by the cilia. On the other hand, fewer and fewer pathogens stick to it. As a result, the amount of germs, viruses and bacteria to which the body is exposed increases by leaps and bounds with increasing dryness.

Dry airway mucous membranes

The aerosol danger: the floating germ droplets in dry air

When the air is dry, the droplets - or aerosols - contaminated with flu and cold viruses dry up. The salt concentration increases very strongly, which means that germs and pathogens can survive for a very long time. In addition, the droplets are lighter and more floating, which causes germs to spread over a wide area! This significantly increases the risk of infection in dry air.