Impacts of window factors and building orientation on energy consumption in residential buildings of humid temperate climatic zone in Iran

This article deals with the research into optimal passive design parameters, such as building’s envelope components and orientation that result in improving energy efficiency. Despite the ever-increasing demand for residential complexes in developing countries like Iran during recent decades, architects and engineers are deprived of the specific guidelines to design energy-saving residential units. The present article aims to monitor the influence of window and orientation variables through the case study in the microclimate region in Iran, which is determined to be a temperate and humid climate. The residential unit is simulated by Design Builder to assess the value of energy used to fulfill heating, cooling, lighting and annual energy consumption regarding controlled variables (shading devices and mechanical and natural ventilation). The window-to-wall ratio (WWR) is evaluated in the range of 15% to 85% for northern and southern external walls. Subsequently, the most conventional range of width to height ratio (WHR) among the regional dwellings reported from the National Road, Housing and Urban Development Research Center is investigated. Additionally, more variables like building orientation (BO) are considered in the parametric analysis as the effective parameter to design passive solar. The considered building is routed on the ground with the azimuth angles from 0° to 360° with 5° increments in a clockwise direction to create 72 building orientation intervals. The results reveal that WWR is recommended to be 15% and 65% on the northern and southern façade, respectively. Furthermore, the aspect ratio of the north-facing windows has the marginal effect on energy saving compared to south-facing windows. Although there is an optimal building orientation, most of the ideal values can be found in the narrow ranges 175° < BO < 190° and 345° < BO < 20°. Findings indicated that the reported variables played an important role in the reduction of energy consumption, particularly in housing units of residential complexes.