The 2 year data showed that the average daily power yield for each month of the vertical DSSC BIPV windowranged from 1.75 to 3.93 kWh/kWp·day (average 2.53 kWh/kWp·day), whereas that of the 30° sloped DSSC BIPVwindow ranged from 2.16 to 5.34 kWh/kWp·day (average 3.60 kWh/kWp·day).The operating power efficiency of the vertical DSSC BIPV window ranged from 2.65 to 4.14% with an averageof 3.40%, whereas that of the sloped DSSC BIPV window was in the range of 2.64–3.63% with a mean of 3.01%.The power generation efficiency of the vertical plane BIPV window was higher than the sloped BIPV window. Incontrast to the average daily power yield, the power efficiency of the vertical window was higher than that of thesloped window, which may be due to the higher efficiency of the DSSCs under overcast conditions. This isconsistent with the power performance of the DSSC BIPV windows according to the sky conditions, whichshowed an increase in power efficiency with increasing cloud cover or decreasing solar intensity