The use of mobile humidifiers in office areas

Project No. BGIA 3101


completed 12/2007


A study into the significance of the air humidity in offices revealed no relationship between the reported complaints and the relative humidity. It may nevertheless be advantageous to keep the humidity in offices above 30% to 40%. This is particularly the case for vocations requiring frequent speaking, as is the case in call centres, for example. Mobile humidifiers are often recommended as a means of increasing the humidity, particularly in the winter months. The effectiveness of such appliances was tested in a study conducted in 2000 by the BAuA (Federal Institute for Occupational Safety and Health). Five mobile humidifiers were tested. The results showed that these appliances are difficult to clean and maintain, and that they are effective in increasing the relative humidity only in rooms up to 40 m² in area. These findings, together with surveys by the BGIA, were to form the basis for a guidance document which is also to contain recommendations for a lower relative humidity limit value and for an intelligent use of mobile humidifiers.


A literature survey was conducted in which information was gathered on the influence of the air humidity upon human health from an occupational health perspective. If possible, a lower limit value for the relative humidity in offices was to be determined from the literature, based upon occupational health considerations. From the findings, a guidance document was to be drawn up for businesses in which the air is not humidified by ventilation or air-conditioning systems.


The studies into the influence of the relative humidity upon human health which were evaluated in the course of the literature survey yield results which in some cases are contradictory. No study was found which provided medical justification for a lower limit value of 30% or which permitted definition of a different limit value. The findings were compiled in a publication. In addition, the VBG, the institution for statutory accident insurance and prevention for the banking, insurance and administration sector, has drawn up a guidance document into which its own findings have been incorporated.

Last Update:

2 May 2016


Financed by:
  • Hauptverband der gewerblichen Berufsgenossenschaften (HVBG)
Research institution(s):
  • Berufsgenossenschaft der Banken, Versicherungen, Verwaltungen
  • Berufsgenossenschaft Druck und Papierverarbeitung


Type of hazard:

-various, work-related health hazards


climate, small and medium-sized enterprises

Description, key words:

mobile humidifiers, offices, call centres, relative humidity, impact upon health, microbial load, dry air, air-conditioning plant, indoor air quality