Impact of Window's Height on Energy Efficiency in Air-Conditioned Office Buildings

In office buildings, working spaces are mainly illuminated by artificial lighting systems which considered being responsible for a major percentage of energy consumption. It is reported that energy consumed by electrical lighting systems can reach to about 20-30% of the total energy end-use in office buildings. The efficient integration of daylighting with artificial lighting using proper lighting control system could result in a significant reduction in energy consumed. Integration of daylighting necessitates efficient window design as it provides most of the transmitted natural lighting. The height of a window has a major role in the determination of the natural light amount which is transmitted into space. Furthermore, the window's height influences the light penetration depth can be reached in the space. This paper aims to investigate the impact of window's height on the window design for energy efficiency in office buildings in a hot-humid climate. In this study, different heights of the window were analyzed with different window areas and glazing types using computer modeling and simulation. The results showed that larger window's height could result in more energy savings, due to the increase of daylight provided to the indoor space. However, the increase of the window's height to more than 1.6 m produced a slight increase in expected energy savings.