More than 16 percent of days lost to illness by office workers result from respiratory infections (Statista Research Department 2020). In particular, professions involving a great deal of speaking suffer from frequent respiratory problems. The frontrunners in terms of rates of absence are employees working in call centres, in customer service and on telephone help lines. In its 2019 report on absence from work, the Scientific Institute of the AOK puts cold-related rates of absence in dialogue marketing professions at an average of 4.8 days per year. One of the reasons for this is the working environment of employees in open-plan offices, where viruses can spread quickly. Protection of the mucous membranes of the respiratory tract and the vocal tract therefore has a major monetary leverage effect in the effort to reduce rates of absence and limitations on productivity. The connection between respiratory complaints and insufficient humidity is now widely acknowledged. In a multi-year study in 2019, researchers at Yale University in the United States clearly demonstrated the influence of low humidity on the survivability and spread of flu viruses. They found that at an optimum humidity of between 40 and 60%, viral infection is minimised and the transmission process is made more difficult. For companies, ensuring a relative humidity level of at least 40% can therefore be a suitable measure to significantly reduce the spread of respiratory infections and the number of illnesses, and to cut costs.

Costs of respiratory infections

For every company, investments must pay off. Employers rely on business criteria as a basis for their decision-making. In practice, however, it is difficult if not impossible to measure investments in the health, well-being and motivation of employees in monetary terms. The external influencing factors and individual circumstances are too varied and complex. Nevertheless, on the basis of statistical facts and realistic assumptions, an attempt will be made here to carry out a cost-benefit analysis that shows the savings potential available to companies through preventive health protection.

Assumptions on costs / non-productive employee time:

1. Employee wage costs € 30,000/year

2. Average 230 working days/year

3. 4.8 days of absence due to respiratory complaints

4. Costs of non-productive time per day of absence for work that is not performed and must be compensated, for example by colleagues working overtime, weighted with a factor of 1.8.

On the basis of the medical evidence and studies available to date, it can be cautiously assumed that optimum humidity levels in the workplace throughout the year can reduce respiratory illnesses by at least 25%. At 25% fewer respiratory complaints, there is an average reduction in rates of absence in companies of 1.2 days of absence per employee. The investment costs for a humidification system to ensure optimum humidity all year round depend on the room size and the number of employees. In simplified terms, the following values can be assumed as a basis for the cost calculation:

Assumed costs of humidification:

1. Room size: Approx. 15 m² per employee (open space with room height approx. 3 m)
2. Investment costs: From € 30 per m²
3. Running costs: € 300 to € 600 per month (including maintenance), depending on the size of the system

If only respiratory complaints are considered, the investment in a humidification system can pay for itself in just two to three years. All other positive effects of optimum humidity on health (e.g. the voice, eyes, skin) and on enhanced productivity are disregarded.