Indoor climate

The air hygiene conditions inside a closed room are different from those around the outdoor area, which is caused by a separate atmosphere, which is also known as a microclimate. The structural and ventilation design of an indoor space is significantly influenced and determined by the climatic factors of the region. Other factors include the type and intensity of use of a building. 

When it comes to the indoor climate, people are not very adaptable. Even slight temperature fluctuations and air movement can cause discomfort. However, thermal comfort cannot be determined on the basis of individual physical parameters. The sensation of warmth in particular depends on physical activity, clothing, air temperature, average radiation temperature, air speed and humidity. A well-insulated room will also contribute to thermal comfort thanks to a fairly homogeneous temperature field.

Air movement in rooms is characterized by the type of circulation and flow (laminar and turbulent). Airflow is perceived by many people as an unpleasantly cold feeling, but at high temperatures airflow can bring a desirable cooling effect and is therefore considered pleasant. Strong air movement increases the body's heat dissipation to the surrounding environment. If this heat dissipation is not compensated for by higher room temperatures, people would feel uncomfortable. Depending on the person's constitution and clothing, the degree of perception and tolerance of airflow varies greatly.

© Fraunhofer WKI | Erik Uhde

Using the comfort graph shown on the left, one can easily determine the climatic conditions for people. Only air humidity and air temperature are considered in the graph. Personal variables are not considered in the graph.

Humidity not only affects our health but is also important in terms of hygiene. High humidity promotes the growth of microorganisms and usually favors biological processes.

When water vapor-saturated air cools down, it eventually falls below the dew point and the water condenses out. Indoors, this usually occurs in thermal bridges or poorly insulated, low-temperature exterior walls. Mold can form in the affected damp areas. To protect the occupants and prevent damage to the building, such condensation must be avoided, for example by improving or repairing the building insulation and by reducing the moisture load in the rooms (see proper ventilation). 

Literature