Developing a user centric building performance measurement scale

There are three basic pillars of the concept of sustainability. These can be considered as economic, environmental and social dimensions. If one of these concepts is missing or not pursued, means that the desired system can not be fully functional. Within the scope of this study, the concept of user satisfaction in office buildings, which is one of the requirements of social dimension of sustainability concept, has been researched. Although concepts of comfort and satisfaction have more comprehensive meaning in human life which are influenced by environmental parameters, psychological environement, physiological state, psychological state, personal factors; hence only the environmental parameters for office occupiers are examined in this study. By the aid of in-depth literature review, expert opinions and conducting a pilot study with building managers in order to gather data from practical implementations of building science; thermal comfort, indoor air quality, acoustic comfort, visual comfort, building design and building services are the parameters that has been determined for the study. The concept of comfort is expressed in its simplest form as the physical consideration of environmental parameters. The concept satisfaction is states as being comfortable and happy. The concept of well-being is stated as being comfortable, healthy and happy. In the present study, it has been found that there is no satisfaction model for office users, covering all of the environmental parameters in the literature. It has been seen that the parameters that are questioned in the current applications are randomly selected and the reason of the complaints related to them is not sufficiently questioned. Even in some studies the reasons for complaints have never been questioned. In addition, generally the purpose of the building performance assessment or post occupancy evaluation schemes used in the industry is to compare the resource efficiency of the building with the state of the building before renovation or the performance of reference buildings. In recent years studies have shown that the concept of user satisfaction, which also affects employee health and productivity, is at the forefront of energy efficiency as well as office buildings. Conventionally reaserchs abaout building performance has focused on the design and construction of new buildings or facilities. However, the role of the existing buildings in comparison to the new building is relatively higher in increasing the total performance of the built environment. Significant deviations between the targeted performance and the actual performance in the buildings have prompted investigators and legislators to seek solutions to improve the performance of the in-use buildings. There are accurate and detailed information requirements about buildings' performance so that shareholders such as designer, property owner, building manager, energy efficiency and green building consultants involved in the use phase of the building operation and renovation process can make effective decisions about the buildings. In the performance evaluations carried out at the buildings, physical measurements such as temperature, humidity, and user feedbacks are used as data of building source usage, building sensor networks, and so on. However, researchers investigating the need for information in building operations and renewal processes, have found that these data in different forms (and formats) can not be presented to support decision makers to make quick and effective decisions. The management of data obtained from physical tests and devices has been relatively improved. Important data such as user feedback and complaints related to the user location that can be obtained from building users are not available to decision makers in existing applications. Moreover standards define and stipulate the conditions required to maximize the health and satisfaction of users. Nontheless some of those observed variables, which are associated with standarts, was found that they had relatively low satisfaction level. Therefore, it was concluded that only compliance with the standards during the project phase was not enough to satisfy user satisfaction. In this context, the utilization from user feedback in the project phase is of great importance both in the design of new buildings and in renovation works. In the hypothesized model, structural equation modeling was chosen in order to be able to express the dimension and direction of causal (regressive) relationships between environmental parameters and user satisfaction. Since the unobserved variables which are hypothesized to reflect occupant satisfaction latent variable such as thermal comfort, indoor air quality, acoustical comfort, visual comfort, building design and building facilities can not directly be measued, they need measurement units (observed variables). The structural equation modeling was chosen as the most appropriate method for confirming the hypothetical model because it can test the causal relationships of variables that are not directly measurable (latent) and measurable (observed). In addition, the structural equation model allows for the elimination of error terms by accounting them to analysis, which is preferred over other multivariate methods. Survey was finalized by in-depth literature review, expert opinions and interviews with building managers. The survey was conducted with 308 office users. Using the user satisfaction indicators in the questionnaire, the satisfaction and importance levels and complaints of the participants about environmental parameters about office buildings were questioned. In the field study section, primarily the descriptive statistics are given followed by statements of finding and results. The robust maximum likelihood procedure was chosen as the estimation method by considering distributional characteristic of data (not-normal), meaurement method of data (1-5 likert scale which is discrete) and sample size (which is 300, by eliminating the missing values).Robust maximum likelihood estimation method was tested by EQS v6.3 because AMOS can not handle with not normal and discrete data as powerful as EQS can. Construct validity of the data was tested by content validity, reliability, convergent validity and discriminant validity procedure. Content validity is the measure of the extent to which the indicator variables represent the coherence of the factors that they represent. The comprehensive analysis of the literature analysis and expert opinion to determine indicator variables provides content validity. Reliability has been verified by using internal consistency. Cronbach's alpha coefficient was used fort o examine the internal consistency. According to the outputs obtained from SPSS software, cronbach alfa values for thermal comfort, indoor air quality, acustical comfort, visual comfort, building design and building services are 0.879, 0.760, 0.763, 0.843, 0.874, 0.870 and 0.956 respevtively. While testing the internal consistency of full model, the croanbach alfa value was obtained as 0.956. Convergent validity is fulfilled by interpreting the standardized factor loadings, obtaining satisfactory fit indices, and achieving average variance extracted (AVE) which are greater than 0.5. Factor loadings within the scope of thermal comfort, indoor air quality, acoustical comfort, visual comfort, building design and building services are all greater than 0.6 except the design which is 0.583. The factor loading for each observed variable under independent constructs are statistically significant. The results of fit indices which are utilized for model (NNFI, RMSEA, CFI, X2/degree of freedom) were satisfactory. The average variance extracted values are equel or above the 0.5 value. Thus convergent validity of construct is provided. When considering discriminant validity, each value in the correlation martice, should be lower than 0.8. As a matter of fact the highest value in corelation matrice is 0.76 which is in between office layout and interior design. In the analysis of the structural equation modeling; all factor loadings were found to be significant and the model was in good fit with the data for both measurement model and structural model. Valus of factor loading for building services, indoor air quality, thermal comfort, building design, acoustical comfort and visual comfort are 0.874, 0.869, 0.893, 0.933, 0.875 and 0.847 respectively. It has been found that user satisfaction level for the environmental parameters is represented by those six factors mentioned above. Those six factors of structural model are found to be statistaically significant. Finally, these factors were interpreted by the aid of information obtained from the literature and the study was completed by making suggestions for future researches. Consideration of indicator variables which are found to affect the user satisfaction, prior to renovation or retrofit process, the decision making mechanism by designers, building owners, green building consultants etc. would be more fluent and practical. In addition to this, throughout the operation process, the level of satisfaction is associated with possible causes of complaint, providing important convenience for detecting and eliminating the source of dissatisfaction. Increased satisfaction of office users is necessary to ensure the persistence of social sustainability. The rise in user satisfaction is important for preserving the health of the users and maintaining life standard of occupants in the long term. Providing personal satisfaction of individuals, protecting their health, providing happiness results with benefits on a macro scale. Thus, the increase in user satisfaction plays an important role in increasing both individual and organizational productivity.