DERIVATION OF THE EVALUATION STRUCTURE OF VIEWS FROM WINDOWS IN COMMERCIAL BUILDINGS: Development of quantitative evaluation method of view effects as a window performance of buildings (part 1)

One of the main aims of daylighting in conventional office buildings is still to reduce electric power consumption of artificial lightings, however, as the efficiency of LEDs has been much improved, the impact of daylighting upon energy savings is getting smaller. Buildings without openings may cause serious problems in visual quality of indoor spaces, therefore it is now more necessary than ever to grasp the psychological values of windows quantitatively. The final purpose of this study is to position the psychological "view effects" as one of the performance items of windows that can be quantitatively evaluated. In this paper, a quantitative evaluation structure of views is derived by analysis of covariance structure based on data obtained from subject evaluation experiments about views from windows in actual commercial buildings. Firstly, users' own criteria for evaluation in views from windows were collected by interviews based on the evaluation grid method (EGM). The EGM was conducted to derive evaluation criteria in views from windows using 31 photographs of the window with different conditions for room use, the floor, floor area, characteristics of viewing landscape, window shape, and window equipment. As a result, items of upper concepts indicating general psychological effects and items of medium concept indicating merits and impressions obtained from environmental factors were derived. Secondary, subjective evaluation experiments about views from windows were conducted for 12 commercial buildings and 26 windows using 19 evaluation items which added "preference" to 18 items derived through the EGM. The height of viewpoint was 1.2 meters above floor level, and its distance from the windows was 2.43 meters. Views from windows with blinds were evaluated under three conditions: slat angle 0°/ 45°/without blind, and views through rolling screens or lace curtains were evaluated under two conditions: fully opened/fully closed. Thirdly, the relationship between psychological value judgement of views from windows and the environmental evaluation conditions of the window was examined through factor analysis and covariance structure analysis based on the results of subjective evaluation experiments. Two factors (“good view”, “openness”) were detected from psychological items by exploratory factor analysis, and four factors (“landscape evaluation”, “range of view”, “clarity”, “sky view”) were detected from environmental items. These factors were sorted out by