Room climate

Factors of the indoor climate

Windows open, windows closed or air conditioning? Air conditioning in offices involves far more than temperature and fresh air. The following is a list of the most important factors.

Room temperature

A room temperature between 21°C and 22°C is recommended for office rooms. This temperature range is comfortable and promotes concentration. The room temperature should not fall below 20°C. If outdoor temperatures are high, it can go up to 26°C. High room temperatures over long periods of time lead to tiredness and poor concentration.

Strong fluctuations of the temperature should be avoided. Temperature fluctuations may be due to the outdoor temperature, e.g. because of direct sunshine, or to the heat generated by technical devices. Strong temperature fluctuations in workplaces can be avoided through room-shading measures such as blinds and windows with solar-protection glass, placing peripheral devices such as printers and copiers in separate rooms, and targeted ventilation and exhaust air facilities.

Surface temperature

Physical contact with surfaces that have poor heat conduction properties can lead to irritation. Consequently, glass plates are not suitable for use as desktops.


Comfortable air quality in office rooms must be ensured for health reasons and also to promote people’s work performance. The relative humidity should be less than 50%, because higher values promote the development of mould.

Humidity can decrease to less than 30% during the winter heating period in particular. This can cause eye irritation and the drying-out of the skin and the respiratory tract. During the winter heating period, you should make sure that the rooms are adequately ventilated and that all the employees drink enough liquids.

Air quality

The main causes of poor air quality are, on the one hand, pollutants such as exhaust gases from construction materials and ozone and, on the other, smells that can be caused by insufficient ventilation. First results of poor air quality are tiredness and poor concentration.

Strict attention should therefore be paid to air quality as early as the construction planning phase. Office furniture materials are stringently regulated. Plants and air conditioners can improve the indoor climate. Printers and copiers should be located in a separate room or at least be screened off from work areas.

Air velocity

At the average temperatures cited above, the air velocity in office rooms should be maximally between 0.1 m/s and 0.15 m/s. At higher temperatures, it may be useful to increase the air velocity for short periods of time. Velocities over 0.2 m/s for longer times should be avoided.