The discussion about the appropriateness of underground spaces for office use has been intensified during the past few decades due to the problem of growing population density and rising land prices, especially in Japan. However, the human reactions towards underground spaces as working environment, are not yet well understood. Furthermore, most of the previous studies have been carried out in western countries.

In the present dissertation existing literature in the area is reviewed, presenting previous research both for and against underground work places. The empirical study consisted of a questionnaire survey comprising 108 employees (22 employees in underground, and 86 workers in above ground offices). The survey focused on: 1) the perceived importance of windows in the work place, 2) the perceived lighting and visual conditions in the underground and above ground offices, and 3) the general perception of the office interior in the surveyed offices.

The results showed clear differences between the underground and above ground offices regarding all three areas of study. The results confirmed that windows were strongly desired in work places, especially by employees working underground and not having windows(p=0.000). The underground employees also evaluated their lighting conditions significantly more negatively (p=O.000) than did the above ground workers, although the actual lighting conditions were very similar. Furthermore, the results showed that the underground office was perceived significantly less pleasant, less stimulating and more enclosed than the above ground offices with windows(p=0.000). Finally, the Japanese subjects in this study showed as strong reactions towards the underground work place as the western subjects of previous studies, implying that the need for windows and contact with the outside are universal human needs, not substantially influenced by cultural or climatic conditions.

Considering that the design and layout of the offices, as well as other environmental factors, such as type and level of artificial lighting, temperature and noise level, were very similar in the underground and above ground offices, it is concluded that the perceived need for windows, and the perception of the lighting conditions and office environment in the present study were more strongly influenced by psychological factors, such as the awareness of being underground and lacking windows and daylight, than by merely the physical characteristics of the work environment.