## 3 Results
### Question 10: Is One IEQ Model Enough for One Investigated Building/Space?  
The occupants' perceptions and preferences for IEQ differed greatly, depending on their characteristics (such as gender, profession, and nationality) and building-related factors (such as the type of building and area). Occupants in different countries had different opinions on the importance of varying IEQ indicators/aspects. For example, air movement was the second most important IEQ indicator to the French but was the least essential IEQ indicator to the Greeks; conversely, noise was significant to the Swedish but hardly mattered to the Portuguese [51]. In the same country, the importance ranking of different IEQ aspects regarding overall IEQ performance might also differ in other buildings [17], even when using the same model-build methods [48]. [PERSON] et al. [48] found that IAQ was the primary aspect of overall IEQ satisfaction in office buildings, followed by thermal, acoustic, and visual comfort. In contrast, thermal comfort was the primary aspect in education buildings, followed by IAQ, acoustic comfort, and visual comfort. Besides this, occupants in private residential buildings thought that air quality was more important than noise, while the opposite opinion was found among the occupants of public residential buildings [39].  
Moreover, occupants' opinions on IEQ aspects might also change with the area, even within the same types of buildings in the same city. For example, thermal comfort was  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Category** & **Explanation** \\ \hline I & A high level of expectation, used for spaces occupied by very sensitive and fragile persons \\ II & A normal level of expectation, used for new buildings and renovations \\ III & An acceptable and moderate level of expectation, used for existing buildings \\ IV & Values outside the criteria for the above categories, used for a limited part of the year \\ \hline \hline \end{tabular}
\end{table}
Table 3: The IEQ categories proposed in EN15251-2007.  
identified as the dominant aspect determining the occupants' IEQ acceptances in typical residential buildings in Hong Kong [49]. At the same time, visual quality was the most critical aspect for the occupants of tiny residential units [85]. Furthermore, even in the same building, the IEQ models developed might also be different; the hierarchy of the IEQ aspects depended on the occupants' gender, the task performed by the occupants, the duration of their stay, and the location of the investigated area [41; 74]. For example, end-users perceived odor as the most critical factor and thermal comfort as the least important factor. At the same time, the noise factor was considered essential to the professional group, and air cleanliness was the least important factor [41]. Occupants who sat in the interior zone thought that lighting conditions were more critical than thermal conditions, compared with those who sat in the perimeter zone who thought that thermal conditions were more important than lighting [38]. To sum up, it seems impossible to propose a universal IEQ model that applies to all occupants or all locations in one building, let alone to different types of buildings.